---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '21658'
abstract:
- lang: eng
text: Dipolar (ℓ = 1) mixed modes have revealed a surprisingly weak differential
rotation between the core and the envelope of evolved solar-like stars. Quadrupolar
(ℓ = 2) mixed modes also contain information regarding internal dynamics but are
very rarely characterised due to their low amplitude and the challenging identification
of adjacent or overlapping rotationally split multiplets affected by near-degeneracy
effects. We aim to extend the broadly used asymptotic seismic diagnostics beyond
ℓ = 1 mixed modes by developing an analogue asymptotic description of ℓ = 2 mixed
modes while explicitly accounting for near-degeneracy effects that distort their
rotational multiplets. We have derived a new asymptotic formulation of near-degenerate
mixed ℓ = 2 modes that describes off-diagonal terms representing the interaction
between modes of adjacent radial orders. This formalism, expressed directly in
the mixed-mode basis, provides analytical expressions for the near-degeneracy
effects. We implemented the formalism within a global Bayesian mode-fitting framework
for a direct fit of all ℓ = 0, 1, 2 modes in the power spectrum density. We were
able to asymptotically model the asymmetric rotational splitting present in various
radial orders of ℓ = 2 modes observed in young red giant stars without the need
for any numerical stellar modelling. We applied our formalism to the Kepler target
KIC 7341231, and it yielded core and envelope rotation rates consistent with previous
numerical modelling while providing improved constraints from the global and model-independent
approach. We also characterised the new target, KIC 8179973, measuring its rotation
rate and mixed-mode parameters for the first time. As our framework relies on
a direct global fit, it allows for much better precision on the asteroseismic
parameters and rotation rate estimates than standard methods, yielding better
constraints for rotation inversions. We have placed the first observational constraints
on the asymptotic ℓ = 2 mixed-mode parameters (ΔΠ2, q2, and εg, 2), thus paving
the way towards the use of asymptotic seismology beyond ℓ = 1 mixed modes.
acknowledgement: 'We thank the referee for their careful and constructive report,
which has substantially enhanced both the quality and clarity of the manuscript.
L. Bugnet and L. Einramhof gratefully acknowledge support from the European Research
Council (ERC) under the Horizon Europe programme (Calcifer; Starting Grant agreement
N°101165631). While partially funded by the European Union, views and opinions expressed
are, however, those of the authors only and do not necessarily reflect those of
the European Union or the European Research Council. Neither the European Union
nor the granting authority can be held responsible for them. The authors acknowledge
the great support and feedback provided during the redaction of this article by
Pr. Rafael García and Pr. Savita Mathur. We would also like to thank Dr. Emily Hatt
for her insights on uncertainty estimates. The authors also thank the members of
the Asteroseismology and Stellar Dynamics group of the Institute of Science and
Technology Austria (ISTA) for very useful discussions: L. Barrault, S.B. Das, K.
Smith. This paper includes data collected by the Kepler mission and obtained from
the MAST data archive at the Space Telescope Science Institute (STScI). Funding
for the Kepler mission is provided by the NASA Science Mission Directorate. STScI
is operated by the Association of Universities for Research in Astronomy, Inc.,
under NASA contract NAS 5–26555. Software: AstroPy (Astropy Collaboration 2013,
2018), Matplotlib (Hunter 2007), NumPy (Harris et al. 2020), SciPy (Virtanen et
al. 2020), emcee (Foreman-Mackey et al. 2013), celerite (Foreman-Mackey et al. 2017),
slepc4py (Dalcin et al. 2011; Hernandez et al. 2005), KADACS (García et al. 2011),
sloscillations (Kuszlewicz et al. 2019, 2023).'
article_number: A321
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Bastien Raymond Bernard
full_name: Liagre, Bastien Raymond Bernard
id: 662f1873-cab4-11f0-a719-8087d302868d
last_name: Liagre
- first_name: Aayush A
full_name: Desai, Aayush A
id: 502cfd30-32c1-11ee-a9a4-d8dad5c6739e
last_name: Desai
- first_name: Lukas
full_name: Einramhof, Lukas
id: f1497a1a-72ef-11ef-b75a-fd877bbf6e8c
last_name: Einramhof
- first_name: Lisa Annabelle
full_name: Bugnet, Lisa Annabelle
id: d9edb345-f866-11ec-9b37-d119b5234501
last_name: Bugnet
orcid: 0000-0003-0142-4000
citation:
ama: 'Liagre BRB, Desai AA, Einramhof L, Bugnet LA. Near-degeneracy effects in quadrupolar
mixed modes: From an asymptotic description to data fitting. Astronomy &
Astrophysics. 2026;707. doi:10.1051/0004-6361/202558023'
apa: 'Liagre, B. R. B., Desai, A. A., Einramhof, L., & Bugnet, L. A. (2026).
Near-degeneracy effects in quadrupolar mixed modes: From an asymptotic description
to data fitting. Astronomy & Astrophysics. EDP Sciences. https://doi.org/10.1051/0004-6361/202558023'
chicago: 'Liagre, Bastien Raymond Bernard, Aayush A Desai, Lukas Einramhof, and
Lisa Annabelle Bugnet. “Near-Degeneracy Effects in Quadrupolar Mixed Modes: From
an Asymptotic Description to Data Fitting.” Astronomy & Astrophysics.
EDP Sciences, 2026. https://doi.org/10.1051/0004-6361/202558023.'
ieee: 'B. R. B. Liagre, A. A. Desai, L. Einramhof, and L. A. Bugnet, “Near-degeneracy
effects in quadrupolar mixed modes: From an asymptotic description to data fitting,”
Astronomy & Astrophysics, vol. 707. EDP Sciences, 2026.'
ista: 'Liagre BRB, Desai AA, Einramhof L, Bugnet LA. 2026. Near-degeneracy effects
in quadrupolar mixed modes: From an asymptotic description to data fitting. Astronomy
& Astrophysics. 707, A321.'
mla: 'Liagre, Bastien Raymond Bernard, et al. “Near-Degeneracy Effects in Quadrupolar
Mixed Modes: From an Asymptotic Description to Data Fitting.” Astronomy &
Astrophysics, vol. 707, A321, EDP Sciences, 2026, doi:10.1051/0004-6361/202558023.'
short: B.R.B. Liagre, A.A. Desai, L. Einramhof, L.A. Bugnet, Astronomy & Astrophysics
707 (2026).
corr_author: '1'
das_tickbox: '1'
date_created: 2026-04-05T22:01:32Z
date_published: 2026-03-01T00:00:00Z
date_updated: 2026-07-08T06:39:05Z
day: '01'
ddc:
- '520'
department:
- _id: LiBu
- _id: IlCa
- _id: GradSch
doi: 10.1051/0004-6361/202558023
external_id:
arxiv:
- '2511.05314 '
file:
- access_level: open_access
checksum: 560cac19dc70184626b85e71a26ee22e
content_type: application/pdf
creator: dernst
date_created: 2026-04-07T09:00:50Z
date_updated: 2026-04-07T09:00:50Z
file_id: '21664'
file_name: 2026_AstronomyAstrophysics_Liagre.pdf
file_size: 12287607
relation: main_file
success: 1
file_date_updated: 2026-04-07T09:00:50Z
fulldoi: https://doi.org/10.1051/0004-6361/202558023
has_accepted_license: '1'
intvolume: ' 707'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
publication: Astronomy & Astrophysics
publication_identifier:
eissn:
- 1432-0746
issn:
- 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Near-degeneracy effects in quadrupolar mixed modes: From an asymptotic description
to data fitting'
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 707
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21896'
abstract:
- lang: eng
text: Redox-mediated flow batteries boost energy density by utilizing dissolved
redox species as charge carriers for solid charge-storage materials. This strategy
strongly depends on the thermodynamics and kinetics between the solid booster
and dissolved redox species. Conventional electrochemical methods often convolute
intrinsic reactivity with mass transport effects, introducing complexity in determining
limiting steps. We propose a strategy that confines solid boosters within recessed
microelectrodes and employs scanning electrochemical microscopy (SECM) to estimate
reaction kinetics between booster and dissolved active redox species. Confining
the solid booster in the recessed microelectrode overcomes mass transport limitations
of dissolved redox species and enables controlled polarization of the booster
material, allowing deconvolution of key rate-determining factors. As an initial
model system, Prussian blue-ferricyanide/ferrocyanide [Fe(CN)6]3−/4− was used
as solid booster and dissolved redox active species, respectively. The methodology
was further explored for copper hexacyanoferrate with N,N,N-2,2,6,6-heptamethylpiperidinyl
oxy-4-ammonium chloride and nickel hydroxide with [Fe(CN)6]3−/4− and extended
to Mn-based Prussian blue analogues in combination with organic redox species.
Our results demonstrate that SECM coupled with the proposed recessed microelectrode
strategy provides a powerful platform to disentangle interfacial kinetics and
guide the rational design of solid booster-dissolved redox species and electrolytes
for high-performance redox-mediated flow batteries.
acknowledgement: "The authors acknowledge funding from the European Union's Horizon
Europe research and innovation programme— European Innovation Council (EIC) under
the grant agreement No 101046742 (MeBattery). P.P. acknowledges the funding from
the European Research Council through a Starting Grant (agreement no. 950038). Dr.
Mahdi Moghaddam, University of Turku, is acknowledged for providing the CuHCF, and
Prof. Hubert Girault, EPFL, is acknowledged for providing the TEMPTMA.\r\nOpen Access
funding enabled and organized by Projekt DEAL."
article_number: e70303
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Carla
full_name: Santana Santos, Carla
last_name: Santana Santos
- first_name: Nomnotho
full_name: Jiyane, Nomnotho
last_name: Jiyane
- first_name: Thomas
full_name: Quast, Thomas
last_name: Quast
- first_name: Maria
full_name: Ibáñez, Maria
id: 43C61214-F248-11E8-B48F-1D18A9856A87
last_name: Ibáñez
orcid: 0000-0001-5013-2843
- first_name: Rubén
full_name: Rubio‐Presa, Rubén
last_name: Rubio‐Presa
- first_name: Pekka
full_name: Peljo, Pekka
last_name: Peljo
- first_name: Wolfgang
full_name: Schuhmann, Wolfgang
last_name: Schuhmann
citation:
ama: Santana Santos C, Jiyane N, Quast T, et al. Evaluating reaction kinetics between
solid booster and dissolved active species in redox‐mediated flow batteries using
scanning electrochemical microscopy. Batteries & Supercaps. 2026;9(5).
doi:10.1002/batt.70303
apa: Santana Santos, C., Jiyane, N., Quast, T., Ibáñez, M., Rubio‐Presa, R., Peljo,
P., & Schuhmann, W. (2026). Evaluating reaction kinetics between solid booster
and dissolved active species in redox‐mediated flow batteries using scanning electrochemical
microscopy. Batteries & Supercaps. Wiley. https://doi.org/10.1002/batt.70303
chicago: Santana Santos, Carla, Nomnotho Jiyane, Thomas Quast, Maria Ibáñez, Rubén
Rubio‐Presa, Pekka Peljo, and Wolfgang Schuhmann. “Evaluating Reaction Kinetics
between Solid Booster and Dissolved Active Species in Redox‐mediated Flow Batteries
Using Scanning Electrochemical Microscopy.” Batteries & Supercaps.
Wiley, 2026. https://doi.org/10.1002/batt.70303.
ieee: C. Santana Santos et al., “Evaluating reaction kinetics between solid
booster and dissolved active species in redox‐mediated flow batteries using scanning
electrochemical microscopy,” Batteries & Supercaps, vol. 9, no. 5.
Wiley, 2026.
ista: Santana Santos C, Jiyane N, Quast T, Ibáñez M, Rubio‐Presa R, Peljo P, Schuhmann
W. 2026. Evaluating reaction kinetics between solid booster and dissolved active
species in redox‐mediated flow batteries using scanning electrochemical microscopy.
Batteries & Supercaps. 9(5), e70303.
mla: Santana Santos, Carla, et al. “Evaluating Reaction Kinetics between Solid Booster
and Dissolved Active Species in Redox‐mediated Flow Batteries Using Scanning Electrochemical
Microscopy.” Batteries & Supercaps, vol. 9, no. 5, e70303, Wiley, 2026,
doi:10.1002/batt.70303.
short: C. Santana Santos, N. Jiyane, T. Quast, M. Ibáñez, R. Rubio‐Presa, P. Peljo,
W. Schuhmann, Batteries & Supercaps 9 (2026).
das_tickbox: '1'
date_created: 2026-05-20T14:32:37Z
date_published: 2026-05-01T00:00:00Z
date_updated: 2026-07-08T06:48:01Z
day: '01'
ddc:
- '530'
department:
- _id: MaIb
doi: 10.1002/batt.70303
file:
- access_level: open_access
checksum: 292d65503a63cc7df92b960627634dad
content_type: application/pdf
creator: dernst
date_created: 2026-05-21T06:54:57Z
date_updated: 2026-05-21T06:54:57Z
file_id: '21904'
file_name: 2026_BatteriesSupercaps_SantanaSantos.pdf
file_size: 756344
relation: main_file
success: 1
file_date_updated: 2026-05-21T06:54:57Z
fulldoi: https://doi.org/10.1002/batt.70303
has_accepted_license: '1'
intvolume: ' 9'
issue: '5'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
publication: Batteries & Supercaps
publication_identifier:
eissn:
- 2566-6223
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
title: Evaluating reaction kinetics between solid booster and dissolved active species
in redox‐mediated flow batteries using scanning electrochemical microscopy
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
_id: '22152'
abstract:
- lang: eng
text: "We study off-diagonal Ramsey numbers \U0001D45F(\U0001D43B,\U0001D43E(\U0001D458)\r\n\U0001D45B)
of \U0001D458-uniform hypergraphs, where \U0001D43B is a fixed linear \U0001D458-uniform
hypergraph and \U0001D43E(\U0001D458)\r\n\U0001D45B is complete on \U0001D45B
vertices. Recently, Conlon, Fox, Gunby, He, Mubayi, Suk, and Verstraëte disproved
the folklore conjecture that \U0001D45F(\U0001D43B,\U0001D43E(3)\r\n\U0001D45B)
always grows polynomially in \U0001D45B. In this paper, we show that much larger
growth rates are possible in higher uniformity. In uniformity \U0001D458 ≥4, we
prove that for any constant \U0001D436 >0, there exists a linear \U0001D458-uniform
hypergraph \U0001D43B for which\r\n\r\n\U0001D45F(\U0001D43B,\U0001D43E(\U0001D458)\r\n\U0001D45B)≥twr\U0001D458−2(2(log\U0001D45B)\U0001D436)."
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Xiaoyu
full_name: He, Xiaoyu
last_name: He
- first_name: Jiaxi
full_name: Nie, Jiaxi
last_name: Nie
- first_name: Yuval
full_name: Wigderson, Yuval
id: 2d0023a0-1567-11f0-833d-d5c1e476d4b5
last_name: Wigderson
- first_name: Hung-Hsun
full_name: Yu, Hung-Hsun
last_name: Yu
citation:
ama: He X, Nie J, Wigderson Y, Yu H-H. Off-diagonal Ramsey numbers for linear hypergraphs.
Combinatorics, Probability and Computing. 2026:1-14. doi:10.1017/s0963548326100443
apa: He, X., Nie, J., Wigderson, Y., & Yu, H.-H. (2026). Off-diagonal Ramsey
numbers for linear hypergraphs. Combinatorics, Probability and Computing.
Cambridge University Press. https://doi.org/10.1017/s0963548326100443
chicago: He, Xiaoyu, Jiaxi Nie, Yuval Wigderson, and Hung-Hsun Yu. “Off-Diagonal
Ramsey Numbers for Linear Hypergraphs.” Combinatorics, Probability and Computing.
Cambridge University Press, 2026. https://doi.org/10.1017/s0963548326100443.
ieee: X. He, J. Nie, Y. Wigderson, and H.-H. Yu, “Off-diagonal Ramsey numbers for
linear hypergraphs,” Combinatorics, Probability and Computing. Cambridge
University Press, pp. 1–14, 2026.
ista: He X, Nie J, Wigderson Y, Yu H-H. 2026. Off-diagonal Ramsey numbers for linear
hypergraphs. Combinatorics, Probability and Computing., 1–14.
mla: He, Xiaoyu, et al. “Off-Diagonal Ramsey Numbers for Linear Hypergraphs.” Combinatorics,
Probability and Computing, Cambridge University Press, 2026, pp. 1–14, doi:10.1017/s0963548326100443.
short: X. He, J. Nie, Y. Wigderson, H.-H. Yu, Combinatorics, Probability and Computing
(2026) 1–14.
date_created: 2026-06-29T10:47:02Z
date_published: 2026-04-14T00:00:00Z
date_updated: 2026-07-08T07:24:54Z
day: '14'
ddc:
- '500'
doi: 10.1017/s0963548326100443
extern: '1'
external_id:
arxiv:
- '2507.05641'
fulldoi: https://doi.org/10.1017/s0963548326100443
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1017/S0963548326100443
mathsc:
- 05D10
- 05D40
- 05C65
month: '04'
oa: 1
oa_version: Published Version
page: 1-14
publication: Combinatorics, Probability and Computing
publication_identifier:
eissn:
- 1469-2163
issn:
- 0963-5483
publication_status: epub_ahead
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Off-diagonal Ramsey numbers for linear hypergraphs
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21161'
abstract:
- lang: eng
text: In many species, sex-biased expression is widespread and thought to contribute
to sexual dimorphism. While bulk RNA-sequencing has been instrumental in identifying
strongly sex-biased genes, it lacks resolution to assess variation across cell-types
and tissue compartments. Using single-nucleus expression data from the Fly Cell
Atlas, we investigate sex differences in adult Drosophila melanogaster. We find
that differences in cell-type composition between the sexes are not a major source
of sex-bias, as for the vast majority of genes, the degree of sex-bias is similar
regardless of whether sex differences in cell-type composition are controlled
for or not. Our analysis confirms a deficit of X-linked male-biased genes in the
body’s somatic tissues that is widespread across cell-types. We also find the
excess of X-linked female-biased genes to be associated with nervous system cells
in the head but with epithelial cells in the body’s somatic tissues, showing that
single-nucleus data crucially resolves sex-bias at the cell-type level. We investigate
dosage compensation (DC) across 15 tissues and 17 cell-types. We observe that
it varies throughout the body. Surprisingly, we observe a lack of DC in a cluster
of main cells within the male accessory glands. This result highlights the importance
of understanding context-dependent DC.
acknowledged_ssus:
- _id: ScienComp
- _id: Bio
acknowledgement: This work was partly funded by an Austrian Science Foundation FWF
ESPRIT fellowship (10.55776/ESP6331524) to C.B. We would like to thank the Vicoso
group for their invaluable input and discussions throughout this work. We thank
Filip Ruzicka for his insightful comments on the manuscript. All computational resources
were provided by the Scientific Computing Unit at ISTA. This research was also supported
through resources provided by the Imaging & Optics Facility (IOF) at ISTA.
article_number: '20252471'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Carolina
full_name: De Castro Barbosa Rodrigues Barata, Carolina
id: 20565186-803f-11ed-ab7e-96a4ff7694ef
last_name: De Castro Barbosa Rodrigues Barata
orcid: 0000-0003-1945-2245
- first_name: Beatriz
full_name: Vicoso, Beatriz
id: 49E1C5C6-F248-11E8-B48F-1D18A9856A87
last_name: Vicoso
orcid: 0000-0002-4579-8306
citation:
ama: de Castro Barbosa Rodrigues Barata C, Vicoso B. Single-nucleus resolution of
sex-biased expression and dosage compensation in Drosophila melanogaster. Proceedings
of the Royal Society B Biological Sciences. 2026;293(2063). doi:10.1098/rspb.2025.2471
apa: de Castro Barbosa Rodrigues Barata, C., & Vicoso, B. (2026). Single-nucleus
resolution of sex-biased expression and dosage compensation in Drosophila melanogaster.
Proceedings of the Royal Society B Biological Sciences. Royal Society of
London. https://doi.org/10.1098/rspb.2025.2471
chicago: Castro Barbosa Rodrigues Barata, Carolina de, and Beatriz Vicoso. “Single-Nucleus
Resolution of Sex-Biased Expression and Dosage Compensation in Drosophila Melanogaster.”
Proceedings of the Royal Society B Biological Sciences. Royal Society of
London, 2026. https://doi.org/10.1098/rspb.2025.2471.
ieee: C. de Castro Barbosa Rodrigues Barata and B. Vicoso, “Single-nucleus resolution
of sex-biased expression and dosage compensation in Drosophila melanogaster,”
Proceedings of the Royal Society B Biological Sciences, vol. 293, no. 2063.
Royal Society of London, 2026.
ista: de Castro Barbosa Rodrigues Barata C, Vicoso B. 2026. Single-nucleus resolution
of sex-biased expression and dosage compensation in Drosophila melanogaster. Proceedings
of the Royal Society B Biological Sciences. 293(2063), 20252471.
mla: de Castro Barbosa Rodrigues Barata, Carolina, and Beatriz Vicoso. “Single-Nucleus
Resolution of Sex-Biased Expression and Dosage Compensation in Drosophila Melanogaster.”
Proceedings of the Royal Society B Biological Sciences, vol. 293, no. 2063,
20252471, Royal Society of London, 2026, doi:10.1098/rspb.2025.2471.
short: C. de Castro Barbosa Rodrigues Barata, B. Vicoso, Proceedings of the Royal
Society B Biological Sciences 293 (2026).
corr_author: '1'
das_tickbox: '1'
date_created: 2026-02-08T23:02:49Z
date_published: 2026-01-28T00:00:00Z
date_updated: 2026-07-08T09:17:41Z
day: '28'
ddc:
- '570'
department:
- _id: BeVi
doi: 10.1098/rspb.2025.2471
external_id:
pmid:
- '41592777'
file:
- access_level: open_access
checksum: d76afebca0a6f112df0146ae2d929f36
content_type: application/pdf
creator: dernst
date_created: 2026-02-16T09:26:02Z
date_updated: 2026-02-16T09:26:02Z
file_id: '21226'
file_name: 2026_RoyalSocPubProceedingsB_Barata.pdf
file_size: 2230841
relation: main_file
success: 1
file_date_updated: 2026-02-16T09:26:02Z
fulldoi: https://doi.org/10.1098/rspb.2025.2471
has_accepted_license: '1'
intvolume: ' 293'
issue: '2063'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 90ef7108-16d5-11f0-9cad-e6e116913473
grant_number: ESP 6331524
name: Does genetic drift set a limit on the adaptive evolution of sex-biased expression?
publication: Proceedings of the Royal Society B Biological Sciences
publication_identifier:
eissn:
- 1471-2954
publication_status: published
publisher: Royal Society of London
quality_controlled: '1'
scopus_import: '1'
status: public
title: Single-nucleus resolution of sex-biased expression and dosage compensation
in Drosophila melanogaster
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 293
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '22254'
abstract:
- lang: eng
text: The global rise of antimicrobial resistance has intensified the search for
new microbial metabolites from underexplored environments and taxonomic groups.
Extreme and geographically isolated habitats such as Antarctic terrestrial ecosystems
represent promising reservoirs of biosynthetic diversity, particularly among rare
and difficult-to-cultivate actinomycetes that may produce chemically diverse metabolites
with potential biotechnological applications. Here, we report the characterization
of kineochelins, a previously undescribed group of siderophores produced by the
Antarctic isolate Actinokineospora sp. UV203, representing a difficult-to-cultivate
actinomycete lineage. Structural elucidation revealed a set of closely related
congeners with a mixed-ligand architecture consistent with metal-chelating activity.
Genome mining combined with transcriptomic analysis identified a dedicated nonribosomal
peptide synthetase-encoding biosynthetic gene cluster responsible for kineochelin
production. Comparative genomic analyses indicated that, although kineochelin
biosynthetic genes share limited similarity with known mixed-ligand siderophores,
their gene content and organization differ substantially, suggesting a distinct
biosynthetic lineage. Functional characterization of the culture supernatant and
an enriched pre-purified kineochelin fraction demonstrated strong and selective
iron chelation, with high affinity for ferric and ferrous iron. Crude culture
extracts inhibited the growth of bacterial strains isolated from the same Antarctic
environment, indicating that kineochelins may contribute to iron-mediated microbial
competition. In addition, kineochelin-enriched pre-purified fractions showed moderate
selective inhibitory activity against the opportunistic yeast pathogen Nakaseomyces
glabratus and a clinical isolate of Saccharomyces cerevisiae associated with invasive
infection. These findings expand the chemical and biosynthetic diversity known
within the genus Actinokineospora and demonstrate that Antarctic rare actinomycetes
represent valuable sources of previously unexplored natural products. The discovery
of kineochelins highlights the potential of genome-guided exploration of polar
microorganisms for identifying bioactive metabolites with relevance for antimicrobial
discovery and biotechnology.
acknowledgement: This work was supported by the Czech Antarctic Research Programme
2025–2027 (VAN 2025) and the University of Vienna via the Research Platform Secondary
Metabolomes of Bacterial Communities (MetaBac). S.K. has received funding from the
European Union's Horizon 2020 research and innovation programme under the Marie
Skłodowska-Curie grant agreement No. 101020356 (DEFCOMANT, https://doi.org/10.3030/101020356)
and MASH StG/CoG (MUNI/SC/1946/2024) by Masaryk University. T.R. and A.L. were funded
in part by the Austrian Science Fund FWF [grant DOI https://doi.org/10.55776/COE7].
M.B. was funded by the Ministry of Health, Czech Republic—conceptual development
of research organization (FNBr, 65269705). The Life Science Compute Cluster LiSC
at the University of Vienna provided the high-performance computing infrastructure
for this study. We thank Julia Ramesmayer and Sara Malinowski (Joint Microbiome
Facility of the Medical University of Vienna and the University of Vienna) for assistance
during high molecular weight extraction and RNA extraction. The authors thank Anna
Fabisikova and Michael Klemm-Abraham from the Mass Spectrometry Centre and the team
of the NMR Centre (both core facilities of the Faculty of Chemistry, University
of Vienna, and members of the Vienna Life Science Instruments) for assistance with
data acquisition. We are thankful to Dr. Jaime Felipe Guerrero Garzón for helpful
discussions on the use of a rrn operon promoter strategy. For open access purposes,
the authors have applied for a CC BY public copyright licence to any author-accepted
manuscript version arising from this submission. Dr. Martin Kello (Department of
Pharmacology, Faculty of Medicine, Pavol Jozef Šafárik University, Košice, Slovakia)
and Dr. Michal Goga (Department of Plant Biology, Faculty of Science and Center
for Interdisciplinary Biosciences, Technology and Innovation Park, Pavol Jozef Šafárik
University in Košice, Košice, Slovakia), funded by VEGA 1/0498/23, are acknowledged
for their assistance with the antiproliferative assays. This work was supported
by Horizon 2020 Framework Programme, 101020356; Universität Wien, MetaBac; Ministry
of Education, Youth and Sports, VAN 2025; Masarykova Univerzita, MUNI/SC/1946/2024;
Austrian Science Fund, 10.55776/COE7; Ministerstvo Zdravotnictví České Republiky,
FNBr, 65269705; Vedecká grantová agentúra Ministerstva školstva, výskumu, vývoja
a mládeže Slovenskej republiky a Slovenskej akadémie vied, VEGA 1/0498/23.
article_number: e70386
article_processing_charge: Yes
article_type: original
author:
- first_name: Stanislava
full_name: Kralova, Stanislava
last_name: Kralova
- first_name: Peter
full_name: Spacek, Peter
last_name: Spacek
- first_name: Johannes
full_name: Gafriller, Johannes
last_name: Gafriller
- first_name: Matej
full_name: Bezdicek, Matej
last_name: Bezdicek
- first_name: Viktoria
full_name: Medvedcova, Viktoria
last_name: Medvedcova
- first_name: Joana
full_name: Séneca, Joana
last_name: Séneca
- first_name: Jay
full_name: Osvatic, Jay
last_name: Osvatic
- first_name: Ulrike
full_name: Grienke, Ulrike
last_name: Grienke
- first_name: Thomas
full_name: Rattei, Thomas
last_name: Rattei
- first_name: Olga N.
full_name: Sekurova, Olga N.
last_name: Sekurova
- first_name: Sergey B.
full_name: Zotchev, Sergey B.
last_name: Zotchev
- first_name: Martin
full_name: Zehl, Martin
id: 8e016d5b-5d77-11f0-86d2-96cdb3922a55
last_name: Zehl
orcid: 0000-0001-9685-0373
- first_name: Alexander
full_name: Loy, Alexander
last_name: Loy
biorxivid: 1
citation:
ama: Kralova S, Spacek P, Gafriller J, et al. Kineochelins - A new group of siderophores
from an antarctic bacterium. Microbial Biotechnology. 2026;19(6). doi:10.1111/1751-7915.70386
apa: Kralova, S., Spacek, P., Gafriller, J., Bezdicek, M., Medvedcova, V., Séneca,
J., … Loy, A. (2026). Kineochelins - A new group of siderophores from an antarctic
bacterium. Microbial Biotechnology. Wiley. https://doi.org/10.1111/1751-7915.70386
chicago: Kralova, Stanislava, Peter Spacek, Johannes Gafriller, Matej Bezdicek,
Viktoria Medvedcova, Joana Séneca, Jay Osvatic, et al. “Kineochelins - A New Group
of Siderophores from an Antarctic Bacterium.” Microbial Biotechnology.
Wiley, 2026. https://doi.org/10.1111/1751-7915.70386.
ieee: S. Kralova et al., “Kineochelins - A new group of siderophores from
an antarctic bacterium,” Microbial Biotechnology, vol. 19, no. 6. Wiley,
2026.
ista: Kralova S, Spacek P, Gafriller J, Bezdicek M, Medvedcova V, Séneca J, Osvatic
J, Grienke U, Rattei T, Sekurova ON, Zotchev SB, Zehl M, Loy A. 2026. Kineochelins
- A new group of siderophores from an antarctic bacterium. Microbial Biotechnology.
19(6), e70386.
mla: Kralova, Stanislava, et al. “Kineochelins - A New Group of Siderophores from
an Antarctic Bacterium.” Microbial Biotechnology, vol. 19, no. 6, e70386,
Wiley, 2026, doi:10.1111/1751-7915.70386.
short: S. Kralova, P. Spacek, J. Gafriller, M. Bezdicek, V. Medvedcova, J. Séneca,
J. Osvatic, U. Grienke, T. Rattei, O.N. Sekurova, S.B. Zotchev, M. Zehl, A. Loy,
Microbial Biotechnology 19 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: The genome sequence and transcriptomic data of strain Actinokineospora
sp. UV203 are available on NCBI (BioProject accession number PRJNA1331526). The
nearly full-length 16S rRNA gene (1395 bp) of strain Actinokineospora sp. UV203
is available on NCBI (accession number PX090945). The NMR data of kineochelin E1
and A1 are deposited in the Natural Products Magnetic Resonance Database (NP-MRD)
under accession numbers NP0352113 and NP0352114, respectively.
date_created: 2026-07-08T09:19:43Z
date_published: 2026-06-01T00:00:00Z
date_updated: 2026-07-13T06:59:08Z
day: '01'
ddc:
- '570'
department:
- _id: MassSpec
doi: 10.1111/1751-7915.70386
external_id:
biorxivid:
- 10.64898/2026.02.23.707395
pmid:
- '42210522'
file:
- access_level: open_access
checksum: 4f735714644f1049b22b014225843d8d
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T06:57:19Z
date_updated: 2026-07-13T06:57:19Z
file_id: '22271'
file_name: 2026_MicrobialBiotechnology_Kralova.pdf
file_size: 2497486
relation: main_file
success: 1
file_date_updated: 2026-07-13T06:57:19Z
fulldoi: https://doi.org/10.1111/1751-7915.70386
has_accepted_license: '1'
intvolume: ' 19'
issue: '6'
keyword:
- Actinokineospora
- Antarctica
- antimicrobial discovery
- biosynthetic gene cluster
- genome mining
- microbial competition
- nonribosomalpeptide synthetase
- siderophores
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
pmid: 1
publication: Microbial Biotechnology
publication_identifier:
eissn:
- 1751-7915
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Kineochelins - A new group of siderophores from an antarctic bacterium
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 19
year: '2026'
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abstract:
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text: Recent studies at high redshift have revealed an enigmatic class of little
red dots (LRDs) with extreme Balmer breaks, stronger than in any stellar atmosphere.
However, it is unclear whether such objects exist at lower redshift, especially
given the low number of LRDs reported at z ≲ 2. Here, we report the discovery
of PAN-BH*-1, an LRD with an extreme Balmer break at z = 1.73, identified from
JWST/NIRCam pure-parallel imaging taken by the PANORAMIC survey, and confirmed
by deep VLT/X-Shooter spectroscopy. The rest-optical to near-infrared spectral
energy distribution of PAN-BH*-1 is consistent with a photospheric continuum with
effective temperature Teff ≈ 4800 K. The broad Hα emission line shows remarkably
deep absorption, stronger than previously measured in any LRD. The absorption
trough spans from −520 to +267 km s−1 with respect to the systemic redshift. The
presence of blue- and red-shifted absorption suggests complex dynamics of the
obscuring gas along the line of sight. We speculate that the absorption trough
can be produced by a thick wind launched from a thick, rotating photospheric disk,
the latter being the source of the red optical continuum. While the source is
unresolved in the rest-optical JWST data (reff < 47 pc), the rest-near-UV Hubble
Space Telescope imaging shows an extended morphology with (formular displayed)
kpc, which we interpret as a host galaxy with a stellar mass of ∼10^8 M⊙, in line
with the narrow Hα emission. The discovery of this object at cosmic noon highlights
the feasibility of systematic searches for extreme LRDs with wide-area facilities
such as Euclid and Roman.
acknowledgement: "IOP Science home\r\nThe Astrophysical Journal Letters\r\nThe American
Astronomical Society, find out more.\r\n\r\nThe following article isOpen access\r\nA
Black Hole Star at Cosmic Noon: Extreme Balmer Break, Photospheric Continuum, and
Broad Absorption by Thick Winds in a Little Red Dot at z = 1.7\r\nAlberto Torralba,
Jorryt Matthee, Andrea Weibel, Rohan P. Naidu, Yilun Ma, Aidan P. Cloonan, Aayush
Desai, Anna de Graaff, Jenny E. Greene, Christian Kragh JespersenShow full author
list\r\n\r\nPublished 2026 June 30 • © 2026. The Author(s). Published by the American
Astronomical Society.\r\nThe Astrophysical Journal Letters, Volume 1005, Number
2\r\nCitation Alberto Torralba et al 2026 ApJL 1005 L37\r\nDOI 10.3847/2041-8213/ae7bfd\r\n\r\nPDFOpens
in a new tab.ePub\r\nAuthors\r\nFigures\r\nTables\r\nReferences\r\nArticle data\r\nPDFOpens
in a new tab.ePub\r\nArticle metrics\r\n122 Total downloads\r\n\r\nShare this article\r\nArticle
information\r\nAbstract\r\nRecent studies at high redshift have revealed an enigmatic
class of little red dots (LRDs) with extreme Balmer breaks, stronger than in any
stellar atmosphere. However, it is unclear whether such objects exist at lower redshift,
especially given the low number of LRDs reported at z ≲ 2. Here, we report the discovery
of PAN-BH*-1, an LRD with an extreme Balmer break at z = 1.73, identified from JWST/NIRCam
pure-parallel imaging taken by the PANORAMIC survey, and confirmed by deep VLT/X-Shooter
spectroscopy. The rest-optical to near-infrared spectral energy distribution of
PAN-BH*-1 is consistent with a photospheric continuum with effective temperature
Teff ≈ 4800 K. The broad Hα emission line shows remarkably deep absorption, stronger
than previously measured in any LRD. The absorption trough spans from −520 to +267
km s−1 with respect to the systemic redshift. The presence of blue- and red-shifted
absorption suggests complex dynamics of the obscuring gas along the line of sight.
We speculate that the absorption trough can be produced by a thick wind launched
from a thick, rotating photospheric disk, the latter being the source of the red
optical continuum. While the source is unresolved in the rest-optical JWST data
(reff < 47 pc), the rest-near-UV Hubble Space Telescope imaging shows an extended
morphology with \r\n kpc, which we interpret as a host galaxy with a stellar mass
of ∼108 M⊙, in line with the narrow Hα emission. The discovery of this object at
cosmic noon highlights the feasibility of systematic searches for extreme LRDs with
wide-area facilities such as Euclid and Roman.\r\n\r\nExport citation and abstract\r\nBibTeXRIS\r\n\r\nPrevious
article in issue\r\nNext article in issue\r\n\r\nOriginal content from this work
may be used under the terms of the Creative Commons Attribution 4.0 licence. Any
further distribution of this work must maintain attribution to the author(s) and
the title of the work, journal citation and DOI.\r\n\r\n1. Introduction\r\nThe unprecedented
sensitivity of JWST has enabled the discovery of a new, abundant population of objects
at redshifts z ≈ 3–9 nicknamed the “little red dots” (LRDs). These are characterized
by their compact rest-frame optical morphology, broad emission lines, and a characteristic
rest-UV to optical “V-shape” in their spectral energy distributions (SED; e.g.,
D. D. Kocevski et al. 2023; V. Kokorev et al. 2024; J. Matthee et al. 2024; I. Labbe
et al. 2025).\r\n\r\nThe nature of LRDs is highly debated (see K. Inayoshi & L.
C. Ho 2025, for a recent overview) as the LRDs show systematic differences with
respect to other types of active galactic nuclei (AGN), such as faintness in X-rays
(e.g., T. T. Ananna et al. 2024; M. Yue et al. 2024), mid-to-far-infrared dust emission
(e.g., G. C. K. Leung et al. 2025; C. C. Williams et al. 2024; I. Delvecchio et
al. 2025; D. J. Setton et al. 2025; M. Xiao et al. 2025), and radio (e.g., G. Mazzolari
et al. 2026; M. A. Latif et al. 2025; K. Perger et al. 2025, see A. J. Gloudemans
et al. 2025).\r\n\r\nA recurring spectral feature of LRDs is the presence of a strong
Balmer break (e.g., D. J. Setton et al. 2025; B. Wang et al. 2024; R. E. Hviding
et al. 2025; W. Q. Sun et al. 2026), in some cases stronger than any star or stellar
population can produce. The two most prominent examples known to date are The Cliff
at z ≈ 3.5 (A. de Graaff et al. 2025a) and MoM-BH* at z ≈ 7.8 (R. P. Naidu et al.
2025). The joint appearance of strong Balmer lines as well as strong Balmer breaks
has been modeled as being due to absorption by a dense, neutral gas with a high
column density in the line of sight to a highly ionizing source (K. Inayoshi & R.
Maiolino 2025; X. Ji et al. 2025; A. Sneppen et al. 2026; A. Torralba et al. 2026).
These observations have sparked the development of new theoretical models, ranging
from a spherical envelope analogous to stellar atmospheres (e.g., M. C. Begelman
& J. Dexter 2026; D. Kido et al. 2025; H. Liu et al. 2025; D. Nandal & A. Loeb 2026)
or a thick accretion disk (e.g., H. Liu et al. 2025, 2026; K. Inayoshi et al. 2025;
Y.-X. Chen et al. 2026).\r\n\r\nBesides their spectral features, the evolution of
the LRD number densities is also in stark contrast to other types of AGNs (e.g.,
K. Inayoshi 2025). At 4 ≲ z ≲ 7, LRDs represent a few percent of the galaxy population
(e.g., D. D. Kocevski et al. 2023, 2025; J. E. Greene et al. 2024; V. Kokorev et
al. 2024; X. Lin et al. 2024; R. Maiolino et al. 2024; J. Matthee et al. 2024),
with number densities of ≳10−5 Mpc−3. The number density does not appear to drop
quickly beyond z > 5 (e.g., J. Zhang et al. 2026), with various LRDs having been
confirmed at z > 8 (V. Kokorev et al. 2023; A. J. Taylor et al. 2025; R. Tripodi
et al. 2025), well beyond the quasar redshift record (F. Wang et al. 2021). Photometric
LRD candidates exist beyond z > 10 (T. S. Tanaka et al. 2025). In turn, the number
density of LRDs seems to decline steeply at z < 4 (e.g., Y. Ma et al. 2026), with
estimates of a number density of ∼10−6 cMpc−3 at z ∼ 2 and even ∼10−10 cMpc−3 at
z ≈ 0.3 (X. Lin et al. 2026). While it is challenging to ensure a uniform selection
function across such a large redshift baseline and dedicated spectroscopic follow-up
of such lower redshift candidates has only just started, it is challenging to attribute
five orders of magnitude to such effects.\r\n\r\nMotivated by the discovery of rare
objects with extreme Balmer breaks at z > 3 and the very small number of known
LRDs at lower redshift, we performed a dedicated search for extreme Balmer break
objects using a template-match approach on a large compilation of JWST NIRCam data
over ≈0.3 deg2 and z ≈ 1.5–7.0. This survey is presented in A. Weibel et al. (2026a).
As part of an ongoing ground-based spectroscopic campaign of LRD candidates at z
∼ 2 (Y. Ma et al. 2026), we followed up the most luminous candidate with a photometric
redshift of z ≈ 2 with the X-Shooter spectrograph on the Very Large Telescope (VLT).
In this Letter, we present the discovery and spectroscopic confirmation of PAN-BH*-1,
a luminous LRD at z = 1.73 with an extreme Balmer break comparable to the strongest
observed in any LRD (and, in general, any astrophysical source). The low redshift
of this source enables high-resolution spectroscopy from ground-based observatories
that is otherwise impossible to obtain at high redshift.\r\n\r\nThroughout this
Letter, we use a ΛCDM cosmology with Ωm = 0.31, ΩΛ = 0.69, and h = 0.677 as described
by Planck Collaboration et al. (2020). All the magnitudes are given in the AB system
(J. B. Oke & J. E. Gunn 1983).\r\n\r\n2. Observations\r\n2.1. Photometry and Source
Selection\r\nWe identified PAN-BH*-1 (ID: PAN-1115, RA, DEC: 40.015835, −1.659363
J2000) as part of a systematic search across ≈0.3 deg2 of JWST NIRCam legacy imaging
comprising at least six filters of coverage (A. Weibel et al. 2026b). Notably, this
dataset includes the Cycle 1 pure parallel survey PANORAMIC (PID: 2514, PIs: Williams
& Oesch; C. C. Williams et al. 2025) that contributes 28 of the 35 independent lines
of sight, thereby enabling the discovery of rare objects such as PAN-BH*-1 across
diverse large-scale structure environments. Specifically, this source was identified
in the footprint j024000m0142 of the PANORAMIC DR1,15 which is adjacent to the A370
field (G. O. Abell et al. 1989), where archival images by the Hubble Space Telescope
(HST) are available from the BUFFALO survey (C. L. Steinhardt et al. 2020). The
HST/ACS images were processed with grizli and also released as part of the PANORAMIC
dataset.\r\n\r\nPAN-BH*-1 is in the outskirts of the A370 lensing cluster, but the
magnification is only μ ≈ 1.05 according to the models from A. Niemiec et al. (2023).
Throughout the rest of the paper, we report the uncorrected flux measurements, since
the effect of magnification (∼5%) is negligible given the uncertainties in the observations
and the lensing model.\r\n\r\nThe search strategy and full photometric selection
are described in a companion paper (A. Weibel et al. 2026a). Briefly, that work
presents a new selection of LRDs as a combination of a “black hole star” template
(BH*; R. P. Naidu et al. 2025) embedded in a host galaxy, instead of the typically
used “V-shaped” selections (e.g., D. D. Kocevski et al. 2025; V. Kokorev et al.
2024). The host galaxies are modeled using eazy’s blue_sfhz templates. The BH*s
are modeled using a novel template set comprising empirical luminosity-based stacks
constructed in W. Q. Sun et al. (2026), the cloudy template from R. P. Naidu et
al. (2025), and by using spectra of prominent LRDs spanning the observed effective
temperature range (I. Labbe et al. 2024; A. de Graaff et al. 2025a; B. Wang et al.
2026).\r\n\r\nPAN-BH*-1 stood out as one of the few sources where the BH* template
effectively dominated all the light over the full wavelength range covered by NIRCam
(hence the name). The redshift of PAN-BH*-1 was estimated to be zphot = 1.85. Follow-up
VLT/X-Shooter spectroscopy confirmed the redshift as zspec = 1.731 (see Section
3.2).\r\n\r\nPAN-BH*-1 is also covered by archival data from the VLT with the HAWK-I
camera in the Ks band (G. B. Brammer et al. 2016) and in data from the Spitzer Space
Telescope in IRAC bands 1 and 3 (3.6 and 5.7 μm), and MIPS 24 μm (P. Capak 2019).
PAN-BH*-1 is detected in the Ks band and in the two IRAC filters. Performing Spitzer
photometry of this source is challenging due to the large point spread function
(PSF) and a neighboring source, especially in the MIPS band. However, the NIRCam
photometry of the neighboring source suggests it has a limited contribution to the
IRAC fluxes. The details of the photometry extraction are described in Appendix
A, and the measured magnitudes in Table 2.\r\n\r\n2.2. VLT/X-Shooter Spectroscopy\r\nPAN-BH*-1
was observed for 5.8 ks with the X-Shooter spectrograph (J. Vernet et al. 2011)
on the VLT as a bright backup target for program 116.294D (PI: Matthee) in visitor
mode on 2025 December 17. The main aim of this program was to confirm candidate
LRDs at cosmic noon (Y. Ma et al. 2026). These observations confirmed the redshift
through the detection of Hα at z = 1.731. A DDT program (ID 116.2AQ0; PI: Matthee)
obtained additional follow-up data of PAN-BH*-1 in service mode for 26.2 ks during
2026 January 10–26, yielding a total exposure time of 8.9 hr. X-Shooter observes
with three arms simultaneously, UVB, VIS, and near-infrared (NIR), covering rest-frame
wavelengths of ≈0.14–0.9 μm, albeit hampered by skyline emission and telluric absorption,
primarily in the rest-frame optical.\r\n\r\nThe observing conditions were clear,
with a seeing ranging from 05 to 07 (median 06). The service mode observations were
primarily conducted during dark nights, with some gray (FLI = 0.03–0.6, median 0.1),
and a typical airmass of 1.35. We used UVB, VIS, and NIR slits with widths 10, 09,
and 09, yielding a nominal resolution of R = 5400, 8900, and 5600, respectively
(FWHM ∼53 km s−1 for NIR). The target acquisition was done using blind offsets from
a reference star, due to the target being too faint for direct acquisition. We used
a standard nodding on the slit pattern, with 4″ nod throws in an ABBA pattern, and
1″ jitters in the NIR arm to improve the sky subtraction. In each observing block
of ≈1 hr, the exposure times were 700, 655, and (2×)365 s for the three arms at
each nod position.\r\n\r\nThe reduction of the X-Shooter data uses a combination
of EsoRex libraries16 and Python code based on the reduction pipeline employed in
J. Matthee et al. (2021). Each observing block was reduced separately. We used standard
stars taken during the observing night for a first-pass flux calibration. Telluric
corrections were applied using the molecfit tool (A. Smette et al. 2015) implemented
in the X-Shooter EsoRex pipeline. Telluric stars were observed during the visitor
nights, but they were not always observed during the service mode observations in
January. For those observations, we took the telluric star that was observed at
the closest observing date. Based on the variation in telluric absorption among
the reference stars taken during this period, we estimate the variation in the transmission
and propagate the uncertainty in the telluric correction. For each observing block,
we then extracted an optimally extracted 1D spectrum using the spatial profile of
the Hα line, thus accounting for seeing variations and (more importantly) minor
errors in the accuracy of the slit pointing. Before median combining these spectra,
we normalize them by the median Hα flux of all observations to account for variations
in slit losses and flux calibrations.\r\n\r\nBesides Hα (integrated S/N = 75) and
Hβ (integrated S/N = 6; Section 3.2), we also detect continuum emission in the best
regions in the H and K bands at 1.6 μm and 2.1 μm, respectively, with a low signal-to-noise
ratio (S/N) of ∼1 per resolution element. Unfortunately, the [O iii] λλ4960, 5008
doublet is undetectable because the observed wavelengths are impacted by very strong
telluric absorption. No other lines or continuum are detected in the X-Shooter spectrum.\r\n\r\n3.
Properties of PAN-BH*-1\r\n3.1. Spectral Shape: A Photospheric Continuum with Strong
Hα Emission\r\nThe photometric SED of PAN-BH*-1 has remarkable similarities with
The Cliff (Figure 1): luminous in the rest optical, with a sudden drop toward the
rest-UV around the Balmer limit, and very weak near-to-mid infrared continuum emission.
With a rough extrapolation of the two HST photometric points using a power-law fit
(fλ ∝ λβ), we obtain a UV slope of β = −0.1 ± 1.2, and MUV = −16.7 ± 0.7. For the
rest-frame optical to NIR data, we fit a Planck blackbody law to the JWST data points,
after subtracting the measured Hα flux (see Section 3.2) from the F200W photometry.
The rest-optical and NIR photometry of PAN-BH*-1 is remarkably well described by
a single temperature blackbody with T = 4204 K (with a best-fit ). We measure the
strength of the Balmer break from the fν ratio F115W/F814W = 7 ± 1, in line with
the Balmer break strengths of The Cliff (; A. de Graaff et al. 2025a)17 and MoM-BH*
(7.8 ± 1.8; R. P. Naidu et al. 2025), measured from JWST/NIRSpec PRISM spectra as
fν,4000–4100/fν,3620−3720. In Figure 2, we compare the Balmer break strength with
the spectroscopic sample of A. de Graaff et al. (2025b), showing that out of 134
sources, only two have breaks significantly above 5. This suggests that PAN-BH*-1
has among the most extreme Balmer breaks known, although we caution that our value
is derived from wide-band photometry with pivot wavelengths corresponding to 4212
and 3042 Å, respectively, rather than from spectroscopy.\r\n\r\nZoom InZoom OutReset
image size\r\nFigure 1. SED of PAN-BH*-1 Top: cutouts from all the HST and JWST
images in which PAN-BH*-1 is covered. It shows a remarkably compact morphology in
all the wavelengths, resolved only in the HST F606W and F814W bands (Section 3.3).
Bottom: photometry from JWST/NIRCam (blue squares), HST/ACS (purple pentagons),
and Spitzer/IRAC+MIPS (red hexagons, and red triangle for the 5σ upper limit). The
empty square is the F200W flux after subtracting the Hα flux measured from X-Shooter
spectroscopy. We show the spectrum of The Cliff for comparison (gray line), shifted
to z = 1.73 and normalized to the F150W flux of PAN-BH*-1. We also show the best-fitting
blackbody spectrum (blue dashed line) and the best model from the synthetic LRD
atmosphere models from H. Liu et al. (2026), shifted to z = 1.73 (green line), undersampled
by a factor of 500 for clarity.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\nZoom InZoom OutReset image size\r\nFigure 2. Spectroscopic sample of LRDs
by redshift and Balmer break strength. We plot the redshift and Balmer break strength
of PAN-BH*-1, and the JWST sample from A. de Graaff et al. (2025b) (purple diamonds),
and three local LRDs in X. Lin et al. (2026), for comparison. We also highlight
three sources with a particularly strong Balmer break: The Cliff (A. de Graaff et
al. 2025a), MoM-BH* (R. P. Naidu et al. 2025), and CAPERS-LRDz9 (A. J. Taylor et
al. 2025). The Balmer break strength of the JWST spectroscopic sample is computed
as fν,4000–4100/fν,3620–3720, whereas the value for PAN-BH*-1 is directly obtained
from the F115W/F814W photometry.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\n3.2. Hα and Hβ Emission Lines\r\nThe Hα profile appears as a complex combination
of a broad line with strong absorption close to the systemic redshift. We fit the
Hα emission line with a similar model as the one used in A. Torralba et al. (2026)
and J. Matthee et al. (2026). The Hα model consists of two Gaussian emission components
(with narrow and intermediate line widths), and a broad symmetric exponential convolved
with the intermediate profile and parameterized as in F. D’Eugenio et al. (2025a).
The absorption is implemented as an opacity law defined as e−τ(λ), where τ(λ) also
follows a single Gaussian velocity distribution (F. D’Eugenio et al. 2025a, 2025b;
A. Torralba et al. 2026). For simplicity, we assume a covering factor of Cf = 1
for the absorbing gas. In previous works, the width of the narrow component is tied
to that of [O iii], assuming both components come from the same region, often interpreted
as the interstellar medium (ISM) of the host galaxy. In this case, we have no information
about [O iii] due to this doublet falling in a wavelength range heavily affected
by strong telluric absorption. We fit the Hα line after masking relevant skylines
and strong telluric absorption bands. The fitted Hα parameters are listed in Table
1 and the best-fit model is shown in Figure 3. The absorption feature is notably
strong, with an equivalent width of EWabs = −148 ± 12 Å with respect to the fitted
continuum and 12.2 ± 0.2 Å if including the broad emission component. The absorption
corresponds to a Balmer optical depth at the line center of , reaching roughly the
continuum level. The FWHM of the single Gaussian fitted to the absorber is 283 ±
\ 8 km s−1, and is offset from the systemic redshift by −94 ± 4 km s−1. We note
that this parameterization is somewhat arbitrary, and we discuss in detail the absorber
properties in Section 4.\r\n\r\nZoom InZoom OutReset image size\r\nFigure 3. Hα
spectrum, and the best fit to our fiducial model. We show the X-Shooter R ∼ 5600
spectrum of the Hα line of PAN-BH*-1, along with the best-fit to the model described
in Section 3.2; total model (red solid line) and individual components (discontinuous
color lines). The red wing of the line is severely affected by telluric absorption,
thus the large uncertainties.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\nTable 1. Properties of PAN-BH*-1\r\n\r\nParameter\tValue\tUnit\r\nWidth
(FWHM; Hα)\r\nExponential\t1257 ± 27\tkm s−1\r\nIntermediate\t687 ± 43\tkm s−1\r\nNarrow\t184
± 12\tkm s−1\r\nAbsorption\t283 ± 8\tkm s−1\r\nFlux (Hα)\r\nExponential\t643 ± 7\t10−18
erg s−1 cm−2\r\nIntermediate\t19 ± 5\t10−18 erg s−1 cm−2\r\nNarrow\t38 ± 3\t10−18
erg s−1 cm−2\r\nTotal\t522 ± 7\t10−18 erg s−1 cm−2\r\nGeneral properties\r\n(LHα/erg
s−1)\t43.046 ± 0.006\t⋯\r\nEW0(Hα)\t520 ± 20\tÅ\r\nSFR(Hα, narrow)a\t2.1 ± 0.2\tM⊙
yr−1\r\nSFR(Hα, narrow)b\t3.3 ± 0.3\tM⊙ yr−1\r\nreff,UV (F606W+F814W)\t\tkpc\r\nreff,opt
(F200W)\t<0.047\tkpc\r\nHα/Hβ (total)\t>9.4\t⋯\r\nHα/Hβ (narrow)\t5 ± 1\t⋯\r\nNotes.
aCalibration from I. G. Kramarenko et al. (2026). bCalibration from R. C. Kennicutt
& N. J. Evans (2012). SFR values calculated assuming no dust attenuation.\r\n\r\nDownload
table as: \r\nASCIITypeset image\r\n\r\nThe Hβ line is marginally detected. After
undersampling the spectrum by a factor 5, a hint of a weak narrow component can
be identified (Figure 4), along with a tentative absorption at the same mean velocity
as in Hα. We fit the best Hα model to the Hβ spectrum, only rescaling it by a multiplicative
factor, and adding a flat continuum component. By doing this, we find an Hβ flux
of (47 ± 8) × 10−18 erg s−1 cm−2 (S/N ≈ 6). Conservatively, we obtain a Balmer decrement
of Hα/Hβ > 9.4 (at a 3σ confidence level), in line with the high decrements found
for the LRD population (e.g., G. P. Nikopoulos et al. 2026; A. de Graaff et al.
2025b; J. Matthee et al. 2026). In Figure 5, we show the Hβ spectrum compared to
the rescaled Hα model. By matching the best-fit Hα profile with the data at the
expected observed wavelength for Hβ (±5000 km s−1), we obtain a better agreement
(, BIC = 1537) than fitting a flat continuum only (, BIC = 1658) with ΔBIC = 121
≫ 10, strongly favoring a detection of a broad Hβ emission line, and securing the
spectroscopic redshift. Similarly, we fit a narrow Gaussian to Hβ with the same
width and velocity as the Hα best-fit model, assuming a completely saturated absorption.
We obtain a Balmer decrement for the narrow component of Hα/Hβ = 5 ± 1, which would
imply a dust extinction of using a J. A. Cardelli et al. (1989) attenuation law,
under the assumption of case B recombination. However, due to the low S/N of Hβ
this result is only tentative, and compatible with a standard Case B value within
∼2σ.\r\n\r\nZoom InZoom OutReset image size\r\nFigure 4. X-Shooter spectrum of Hα
and Hβ of PAN-BH*-1 (blue). We compare to the spectrum of The Cliff (gray; data
from JWST DDT #9433), normalized in each panel to the flux of PAN-BH*-1 in the range
v ∈ (−3000, −2000) km s−1. Due to the low S/N, the Hβ spectrum of PAN-BH*-1 is rebinned
to a coarser grid by a factor 5, after masking the most relevant skylines.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\nZoom InZoom OutReset image
size\r\nFigure 5. Hβ spectrum. The spectrum is rebinned by a factor of 10 with inverse
variance flux weighting for visual clarity, due to the low S/N. We compare to the
best-fit Hα model, scaled by a factor of 0.112. In the bottom panel, we show the
χ residuals between the spectrum and the rescaled Hα model in black, and for only
the continuum in pink (ΔBIC = 121 strongly favoring the presence of a broad Hβ line).\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\n3.3. Spatial Morphology\r\nIn
order to assess whether PAN-BH*-1 is spatially resolved, we use the Bayesian profile
fitting software pysersic (I. Pasha & T. B. Miller 2023)18 to fit a single Sérsic
profile to the JWST and HST imaging data of PAN-BH*-1. For JWST/NIRCam, we choose
F200W as the filter with the highest S/N in the short wavelength channel, benefiting
from a high spatial resolution and probing rest-frame optical wavelengths. To model
its PSF, we use version 2.2.0 of the stpsf software (formerly webbpsf, M. D. Perrin
et al. 2014). For the two HST bands F606W and F814W, we instead construct empirical
PSFs from public imaging data in the GOODS-S field following A. Weibel et al. (2024).
In all three bands, we sample the posterior with the No U-turn sampler in two chains
with 1000 warm-up and 2000 sampling steps each. We find that PAN-BH*-1 is unresolved
with NIRCam in F200W where the effective radius converges toward the edge of the
prior at 0.25 pixels. Using the 95th percentile of the posterior chains as an upper
limit on the effective radius, we find a rest-optical size of reff < 47 pc.\r\n\r\nPAN-BH*-1
appears to be resolved in the HST images corresponding to rest-frame pivot 0.2 and
0.3 μm, respectively. Due to the low signal-to-noise of the F606W and F814W photometry,
we fit both bands simultaneously fixing all the morphological parameters in both
images. We measure physical effective radii of kpc (see Appendix B). The modest
stretching by the foreground A370 lensing cluster could imply a correction of ∼10%
to the measured radius (A. Niemiec et al. 2023), which we disregard given the uncertainties.
These measured sizes are consistent with the typical sizes for galaxies with a stellar
mass ≲ 109 M⊙ at z = 1.75 (A. van der Wel et al. 2014). These findings are consistent
with the scenario of a compact LRD “engine” dominating the rest-optical light embedded
in a host galaxy, whose contribution becomes significant blueward of the Balmer
break (see A. P. Cloonan et al. 2026, for a relevant discussion).\r\n\r\n4. Absorber
Kinematics\r\nAs described in Section 3.2, the velocity distribution of the absorber
is empirically modeled with a Gaussian, which we find has a central velocity of
−94 ± 4 km s−1 relative to the redshift of the narrow emission component (adopted
as systemic). The absorption trough extends from negative to positive velocities
with respect to the redshift of the narrow component, but also with respect to the
center of the symmetric exponential wings. However, there are several degeneracies
between the shape of the absorber and other components of the emission line, such
as the narrow central emission (see Section 3.2). Furthermore, direct interpretation
of the absorber center velocity shift is challenging in an optically thick gas with
presumably complex dynamics, and it does not necessarily trace bulk motion. A more
robust, physically motivated pair of quantities is the minimum and maximum absorber
velocities. We define them as the values where the transmission of the Balmer absorber
increases to 99%, km s−1 and km s−1. These values trace the largest velocities
in the line of sight of gas with significant Balmer absorption. The absorbing trough
extends over 787 ± 17 km s−1 under this definition. The values of and are relatively
agnostic to the choice of the shape of the absorber, since they are determined by
the wavelength where the line profile deviates from a broad, symmetric exponential
profile. In Figure 6, we illustrate three proposed configurations of the velocity
distribution of the absorbing gas that could explain the shape of the observed Balmer
absorption, and we discuss these scenarios below.\r\n\r\nZoom InZoom OutReset image
size\r\nFigure 6. Geometric configurations for the absorber. We illustrate three
scenarios that could give rise to the observed Balmer absorption in PAN-BH*-1. In
scenario (a), the obscuring agent is a thick screen of gas with a certain bulk velocity,
and turbulent motions produce the broadening of the absorption trough. In (b), there
are two (or more) absorbers with opposite velocities in the line of sight. These
first two scenarios are dynamically unstable; therefore, variability is expected
in the absorption. Lastly, in (c), we observed an extended source through a disk
wind with a rotational component (vϕ) in addition to the poloidal (nonazimuthal)
velocity (vp). In the last scenario, the redshifted absorption is produced by streamlines
that oppose the observer when projected along the line of sight, despite the fact
that the gas is outflowing from the central source.\r\n\r\nDownload figure:\r\n\r\nStandard
imageHigh-resolution image\r\n4.1. Unstable Gas Flows?\r\nThe fact that there is
significant absorption at both negative and positive velocities with respect to
the systemic redshift cannot be simply explained by an axisymmetric outflowing or
inflowing wind. In the case of observing a compact object through a spherically
symmetric, nonturbulent bulk flow, a classical P Cygni profile is expected, with
a purely blueshifted absorption (or redshifted if the wind is infalling). The fact
that we also see redshifted absorption rules out this simple scenario. In principle,
turbulent motions could also produce broadening of the absorbing medium (scenario
a in Figure 6). However, the required turbulent velocity dispersion σturb ≈ 120
km s−1 (from the Gaussian fit in Section 3.2) is comparable to the mean velocity
of the absorption trough, meaning that turbulence dominates the gas flow. In such
a case, strong variability of the absorption profile would be expected, given the
typical dynamical crossing times (see Sect. 4.1 in F. D’Eugenio et al. 2025b). For
example, for a radius of 1016 cm (e.g., A. Torralba et al. 2026) and a mass of 106
M⊙, the dynamical freefall time is yr. Moreover, the turbulent velocity would be
highly supersonic, and the dissipation timescale would be comparable to the dynamical
time (e.g., M.-M. Mac Low 1999). Alternatively, in the context of a strong Balmer
absorber at z ∼ 7, F. D’Eugenio et al. (2026) recently discussed a “breathing mode”
scenario with cyclic inflows and outflows along the same line of sight, with the
gas being in different phases at different depths (scenario b in Figure 6; see also
K. Park et al. 2017). In this case, the same arguments regarding the stability of
the absorber would apply, and absorber variability is expected on observed timescales
of ∼5 yr (for a source at z = 1.7), which is testable with future observations.\r\n\r\n4.2.
The Case for the Disk Wind Hypothesis\r\nAn alternative, dynamically stable scenario
is a disk wind configuration (scenario c in Figure 6). Here, the wind would be launched
from a thick disk near the central engine, which we speculate could be the source
of the optical continuum emission (e.g., H. Liu et al. 2025, 2026; L. Zwick et al.
2025; Y.-X. Chen et al. 2026). A rotating disk would imprint to the wind an azimuthal
velocity component (vϕ). Observations at specific lines of sight, particularly for
high inclination angles (close to edge-on) where the rotational component dominates
the poloidal velocity, can give rise to both blueshifted and redshifted absorption
features (D. Proga et al. 2000; P. B. Hall et al. 2002, 2013; D. Proga & T. R. Kallman
2004; M. Giustini & D. Proga 2012). Most observed LRDs have blueshifted P Cygni–like
absorbers (J. Matthee et al. 2026), which can be naively interpreted as a uniformly
expanding shell. The low incidence of redshifted Balmer absorbers in LRD spectra
(e.g., I. Labbe et al. 2024; A. de Graaff et al. 2025a; F. D’Eugenio et al. 2025b,
2026; Y. Ma et al. 2026) can therefore be explained by the requirement of high inclination
angles to observe such features (see also A. Sneppen et al. 2026). Such a picture
is broadly in line with disk wind models for AGN with broad absorption lines (e.g.,
P. B. Hall et al. 2002; H. Zhou et al. 2019) and around stars with circumstellar
disks (e.g., J. Erkal et al. 2022), such as accreting T Tauri stars (S. Edwards
et al. 2006) or cataclysmic variables (D. Proga 2003).\r\n\r\n4.3. Implications
of Rotating Winds for the Emission Lines of LRDs\r\nThe disk wind hypothesis would
imply that a photosphere in the shape of a rotating disk is the source of the optical
continuum emission, and drives winds that can explain the observed absorption trough.
Emission lines originating in a thin rotating disk would have a double-peaked profile
in the idealized case (for most inclination angles), but this is not necessarily
true if the disk is not sufficiently thin (e.g., N. Murray & J. Chiang 1997), for
instance, in the case of a puffed-up disk associated with super-Eddington accretion
(e.g., H. Liu et al. 2026). In addition, most line emission would not be produced
directly at the base of the disk, but slightly outside (e.g., via collisional cooling
or residual recombination; A. Torralba et al. 2026), where the rotational velocity
is lower, and the dynamics are complex (e.g., G. A. Shields 1977).\r\n\r\nThe Balmer
lines of most LRDs are dominated by broad, symmetric exponential components that
are associated with broadening by electron scattering (e.g., V. Rusakov et al. 2026;
J. Matthee et al. 2026). For PAN-BH*-1, the Hα line profile of PAN-BH*-1 is compatible
with a broad exponential profile emerging through a dense wind where the absorption
trough is produced. In dense gas with a large column density of neutral hydrogen,
and optically thick to Balmer transitions (NHI,2s ≳ 1014 cm−2), resonant scattering
effects become important. Crucially, resonant scattering impacts Hα and Hβ differently
(e.g., S.-J. Chang et al. 2026), hence the 3D radiative transfer and photon redistribution
of both lines may produce different profiles (see, e.g., Figure 2 in D. Proga 2003).
Therefore, the empirical fitting and interpretation of the absorption profiles becomes
nontrivial. Dedicated radiative transfer modeling is necessary to study such effects,
and they can be tested in other emission lines with high optical depth, such as
He i λ10830 Å, or resonant lines like C iv λ1550.\r\n\r\n5. Implications for the
Galaxy and Black Hole Masses\r\n5.1. Properties of the Host Galaxy\r\nAssuming that
the narrow component of Hα corresponds to ISM emission in the host galaxy, we compute
the associated star formation rate using the local calibration from R. C. Kennicutt
& N. J. Evans (2012) and assuming no dust attenuation. We obtain SFR(Hα) = 3.3 ±
0.3 M⊙ yr−1. A somewhat lower value of SFR(Hα) = 2.1 ± 0.2 M⊙ yr−1 is obtained using
the high-redshift (z ≳ 4) calibrations in I. G. Kramarenko et al. (2026), which
might be more appropriate for a young dwarf galaxy with a bursty star formation
history. The star formation rates are low, but in line with a main-sequence galaxy
with (extrapolating the relation from J. S. Speagle et al. 2014). Assuming zero
dust attenuation, the UV absolute magnitude (MUV = −16.7 ± 0.7; Section 3.1) would
imply SFR(UV) = 0.18 ± 0.12 M⊙ yr−1 (R. C. Kennicutt & N. J. Evans 2012). The discrepancy
between the UV and Hα inferred star formation rate suggests there is some amount
of dust attenuation in the host galaxy.\r\n\r\nWe derive a dynamical mass from the
width of the narrow component Hα line and the estimated UV size as , adopting the
empirical virial correction K(n)K(q) from A. van der Wel et al. (2022), where K(n)
and K(q) are functions of the best-fit ellipticity and Sérsic index (see Appendix
B). Adopting a Mdyn/M* factor of 40 as found by A. de Graaff et al. (2024) for dwarf
galaxies at high redshift, we infer a stellar mass of . However, the Mdyn/M* is
very uncertain in this regime, and the uncertainty can span over 1 dex (A. Saldana-Lopez
et al. 2025). We advise caution in interpreting this result, as there are large
uncertainties in the measurements of the narrow Hα component, the HST morphology,
and the empirical relations used.\r\n\r\nAs discussed in Section 4, the absorption
profile is compatible with broadening by a rotating disk wind, and numerical modeling
of such configurations often predicts a narrow component arising from increased
transmission due to purely kinematic effects in the wind geometry (D. Proga et al.
2000; D. Proga 2003; D. Proga & T. R. Kallman 2004). This would be an alternative
explanation for at least part of the narrow component flux. On the other hand, most
LRDs present narrow [O iii] emission that is often associated with the host galaxy.
Indeed, the ionized gas producing [O iii] emission should have associated emission
in the Hα and higher-order Balmer lines. However, constraining this component largely
depends on the assumptions on dust attenuation or ISM conditions, and requires very
high S/N and resolution data. Deep, space-based follow-up observations of PAN-BH*-1
would be very constraining for the wind kinematics (e.g., by the joint analysis
of Hβ) and to assess whether a narrow component comes from a host galaxy (e.g.,
by comparing to a narrow Hβ component or [O iii] λλ4960, 5008).\r\n\r\n5.2. Black
Hole Mass From Photosphere Models\r\nThe general physical setup of LRDs is an open
debate, and their masses are a major unknown. Due to the multiple differences with
respect to the classical AGN population, the validity of standard virial calibrations
has been questioned (e.g., V. Rusakov et al. 2026; J. E. Greene et al. 2026; A.
Sneppen et al. 2026; A. Torralba et al. 2026, although see, e.g., M. Brazzini et
al. 2025, 2026; J. Scholtz et al. 2026 for an alternative interpretation).\r\n\r\nOne
can obtain a mass estimate assuming a system in radiative equilibrium with Lbol/LEdd
= 1 (e.g., H. Umeda et al. 2026); this yields a total mass of ≈106 M⊙, using the
bolometric luminosity from integrating the best-fit blackbody in Section 3.1. Recently,
H. Liu et al. (2026) developed a synthetic spectral library of LRD atmosphere models.
In these models, the density of the photosphere is regulated by the net surface
gravity of an optically thick atmosphere, enabling constraints on the mass of the
system. We fit the JWST photometry of PAN-BH*-1 using the models from H. Liu et
al. (2026), assuming a negligible contribution from a host galaxy to the optical
continuum. The best-fit model has effective temperature Teff = 4800 K, surface gravity
, and metallicity (; see Figure 1). The best-fit implies a total mass of the system
(BH plus gas) of (Equation (6) in H. Liu et al. 2026, assuming hydrostatic equilibrium).
For the second and third best fits, we obtain and −2, respectively (, respectively;
with the same metallicity and effective temperature), which would imply lower limits
to the system mass between and 4. The bolometric luminosity of PAN-BH*-1 (from the
integral of the best-fit green curve in Figure 1) implies an Eddington luminosity
ratio of L/LEdd ≲ 13, assuming the best-fit mass from the H. Liu et al. (2026) models.
The elevated Eddington ratio is in line with the hypothesis of a radiation-driven
wind discussed in Section 4, and allows for somewhat larger system masses. The low
masses obtained with this model, combined with the stellar mass inferred from dynamical
arguments for the host galaxy (Section 3.3) set lower limits to the BH-to-stellar
mass ratio of MBH/M* ≳ 10−4–10−2, which are compatible with the relations observed
in the Local Universe, within the large uncertainties (A. E. Reines & M. Volonteri
2015).\r\n\r\n6. Conclusions\r\nIn this Letter, we presented the discovery and spectroscopic
confirmation of PAN-BH*-1, an LRD with an extreme Balmer break at z = 1.731. The
strength of the Balmer break (F115W/F814W = 7 ± 1) is comparable to the most extreme
LRDs known, The Cliff (A. de Graaff et al. 2025a) and MoM-BH* (R. P. Naidu et al.
2025). We summarize the observations and our main conclusions as follows.\r\n\r\n\r\n1.
\ \r\nWe obtained deep VLT/X-Shooter spectroscopy of PAN-BH*-1. The Hα emission
line is luminous and broad (LHα = 1043 erg s−1), and has an unusually strong absorption.
Hβ is detected with an S/N ≈ 6, and we conservatively estimate a lower limit for
the Balmer decrement of Hα/Hβ > 9.4 (at a 3σ confidence level), in line with other
LRDs in the literature (e.g., A. de Graaff et al. 2025b; G. P. Nikopoulos et al.
2026).\r\n2. \r\nThe absorption trough spans from −520 to 267 km s−1 (at a transmission
level of 99%). We interpret the presence of blue- and redshifted absorption as produced
by a disk wind, analogous to those analyzed in the context of broad absorption line
quasars or accreting stars. This hypothesis would imply that the source of the optical
continuum is likely a thick photospheric disk.\r\n3. \r\nWe detect a narrow Hα
component (FWHM = 184 ± 12 km s−1), which we interpret as probing a host galaxy
with M* ≈ 108 M⊙ and SFR = 2–3 M⊙. This interpretation is in line with the extended
rest-NUV morphology measured in the HST bands (\r\n kpc).\r\n4. \r\nBy fitting
the synthetic atmosphere models of H. Liu et al. (2026), we estimate a system mass
(BH+envelope) of 104–106 M⊙. The inferred masses, together with the stellar mass
inferred from morphology and narrow emission line dynamics, imply BH-to-stellar
mass ratios of 10−2–10−4, close to the extrapolated trend in the local Universe
(A. E. Reines & M. Volonteri 2015).\r\n5. \r\nThe confirmation of this source at
cosmic noon (magnitude of ≈22 in the K band, Hα flux ≈5 × 10−16 erg s−1 cm−2) proves
the feasibility of detecting extreme LRDs at such epochs with wide-area spectroscopic
surveys like Euclid or the forthcoming Nancy Grace Roman Space Telescope.\r\n\r\nAcknowledgments\r\nA.T.
thanks Debasish Dutta and Tamara Bogdanović for useful conversations about stellar
and AGN winds.\r\n\r\nWe thank the scientific referee for the useful and constructive
feedback, which helped improve the quality of this paper.\r\n\r\nJ.M. and A.T. acknowledge
funding by the European Union (ERC, AGENTS, 101076224). The work of CCW is supported
by NOIRLab, which is managed by the Association of Universities for Research in
Astronomy (AURA) under a cooperative agreement with the National Science Foundation.
A.P.C. warmly acknowledges the support of the National Science Foundation through
the NSF Graduate Research Fellowship Program. A.d.G. acknowledges support from a
Clay Fellowship awarded by the Smithsonian Astrophysical Observatory.\r\n\r\nBased
on observations made with ESO Telescopes at the Paranal Observatory under program
IDs 116.294D and 116.2AQ0.\r\n\r\nThis work is based in part on observations made
with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the
Mikulski Archive for Space Telescopes at the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in Astronomy,
Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated
with programs #2514 and #9433. C.C.W. gratefully acknowledges support for program
JWST-GO-2514 provided by NASA through a grant from the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in Astronomy,
Inc., under NASA contract NAS 5-03127. The authors acknowledge the team led by co-PIs
R. Maiolino and F. D’Eugenio for developing their observing program with a zero-exclusive-access
period.\r\n\r\nThis research is based on observations made with the NASA/ESA Hubble
Space Telescope obtained from the Space Telescope Science Institute, which is operated
by the Association of Universities for Research in Astronomy, Inc., under NASA contract
NAS 5–26555. These observations are associated with program #15117.\r\n\r\nThe JWST
and HST data presented in this article were obtained from the Mikulski Archive for
Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations
analyzed can be accessed via doi:10.17909/ydwx-st06.\r\n\r\nThis work is based in
part on observations made with the Spitzer Space Telescope, which was operated by
the Jet Propulsion Laboratory, California Institute of Technology under a contract
with NASA. The Spitzer data used in this work can be found in doi:10.26131/IRSA3.\r\n\r\nThis
work was supported by the International Space Science Institute (ISSI) in Bern,
through ISSI International Team project #25-659 “Little Red Dots, Big Open Questions.”\r\n\r\nJWST
cartoon in Figure 6, credit: NASA.\r\n\r\nFacilities: VLT:Kueyen - Very Large Telescope
(Kueyen) (X-Shooter), VLT:Yepun (HAWK-I), JWST - James Webb Space Telescope (NIRCam,
NIRspec), HST - Hubble Space Telescope satellite (ACS), Spitzer - Spitzer Space
Telescope satellite (IRAC, MIPS) - .\r\n\r\nSoftware: astropy (Astropy Collaboration
et al. 2013, 2018; Astropy Collaboration et al. 2022), NumPy (C. R. Harris et al.
2020), SciPy (P. Virtanen et al. 2020), pysersic (I. Pasha & T. B. Miller 2023),
stpsf (M. D. Perrin et al. 2014), lmfit (M. Newville et al. 2014), EsoRex (ESO CPL
Development Team 2015), Claude (used for Python coding; https://claude.ai/), SEP
(K. Barbary 2016)."
article_number: L37
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Alberto
full_name: Torralba Torregrosa, Alberto
id: 018f0249-0e87-11f0-b167-cbce08fbd541
last_name: Torralba Torregrosa
orcid: 0000-0001-5586-6950
- first_name: Jorryt J
full_name: Matthee, Jorryt J
id: 7439a258-f3c0-11ec-9501-9df22fe06720
last_name: Matthee
orcid: 0000-0003-2871-127X
- first_name: Andrea
full_name: Weibel, Andrea
last_name: Weibel
- first_name: Rohan P.
full_name: Naidu, Rohan P.
last_name: Naidu
- first_name: Yilun
full_name: Ma, Yilun
last_name: Ma
- first_name: Aidan P.
full_name: Cloonan, Aidan P.
last_name: Cloonan
- first_name: Aayush A
full_name: Desai, Aayush A
id: 502cfd30-32c1-11ee-a9a4-d8dad5c6739e
last_name: Desai
- first_name: Anna
full_name: De Graaff, Anna
last_name: De Graaff
- first_name: Jenny E.
full_name: Greene, Jenny E.
last_name: Greene
- first_name: Christian Kragh
full_name: Jespersen, Christian Kragh
last_name: Jespersen
- first_name: Ivan
full_name: Kramarenko, Ivan
id: 9a9394cb-3200-11ee-973b-f5ba2a8b16e4
last_name: Kramarenko
orcid: 0000-0001-5346-6048
- first_name: Sara
full_name: Mascia, Sara
id: edaf889c-c7cd-11ef-ab1b-bb28c431bd29
last_name: Mascia
- first_name: Pascal A.
full_name: Oesch, Pascal A.
last_name: Oesch
- first_name: Wendy Q.
full_name: Sun, Wendy Q.
last_name: Sun
- first_name: Christina C.
full_name: Williams, Christina C.
last_name: Williams
citation:
ama: 'Torralba Torregrosa A, Matthee JJ, Weibel A, et al. A black hole star at cosmic
noon: Extreme Balmer break, photospheric continuum, and broad absorption by thick
winds in a Little Red Dot at z = 1.7. The Astrophysical Journal Letters.
2026;1005(2). doi:10.3847/2041-8213/ae7bfd'
apa: 'Torralba Torregrosa, A., Matthee, J. J., Weibel, A., Naidu, R. P., Ma, Y.,
Cloonan, A. P., … Williams, C. C. (2026). A black hole star at cosmic noon: Extreme
Balmer break, photospheric continuum, and broad absorption by thick winds in a
Little Red Dot at z = 1.7. The Astrophysical Journal Letters. IOP Publishing.
https://doi.org/10.3847/2041-8213/ae7bfd'
chicago: 'Torralba Torregrosa, Alberto, Jorryt J Matthee, Andrea Weibel, Rohan P.
Naidu, Yilun Ma, Aidan P. Cloonan, Aayush A Desai, et al. “A Black Hole Star at
Cosmic Noon: Extreme Balmer Break, Photospheric Continuum, and Broad Absorption
by Thick Winds in a Little Red Dot at z = 1.7.” The Astrophysical Journal Letters.
IOP Publishing, 2026. https://doi.org/10.3847/2041-8213/ae7bfd.'
ieee: 'A. Torralba Torregrosa et al., “A black hole star at cosmic noon:
Extreme Balmer break, photospheric continuum, and broad absorption by thick winds
in a Little Red Dot at z = 1.7,” The Astrophysical Journal Letters, vol.
1005, no. 2. IOP Publishing, 2026.'
ista: 'Torralba Torregrosa A, Matthee JJ, Weibel A, Naidu RP, Ma Y, Cloonan AP,
Desai AA, De Graaff A, Greene JE, Jespersen CK, Kramarenko I, Mascia S, Oesch
PA, Sun WQ, Williams CC. 2026. A black hole star at cosmic noon: Extreme Balmer
break, photospheric continuum, and broad absorption by thick winds in a Little
Red Dot at z = 1.7. The Astrophysical Journal Letters. 1005(2), L37.'
mla: 'Torralba Torregrosa, Alberto, et al. “A Black Hole Star at Cosmic Noon: Extreme
Balmer Break, Photospheric Continuum, and Broad Absorption by Thick Winds in a
Little Red Dot at z = 1.7.” The Astrophysical Journal Letters, vol. 1005,
no. 2, L37, IOP Publishing, 2026, doi:10.3847/2041-8213/ae7bfd.'
short: A. Torralba Torregrosa, J.J. Matthee, A. Weibel, R.P. Naidu, Y. Ma, A.P.
Cloonan, A.A. Desai, A. De Graaff, J.E. Greene, C.K. Jespersen, I. Kramarenko,
S. Mascia, P.A. Oesch, W.Q. Sun, C.C. Williams, The Astrophysical Journal Letters
1005 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: "Based on observations made with ESO Telescopes at the
Paranal Observatory under program IDs 116.294D and 116.2AQ0.\r\n\r\nThis work is
based in part on observations made with the NASA/ESA/CSA James Webb Space Telescope.
The data were obtained from the Mikulski Archive for Space Telescopes at the Space
Telescope Science Institute, which is operated by the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These
observations are associated with programs #2514 and #9433. C.C.W. gratefully acknowledges
support for program JWST-GO-2514 provided by NASA through a grant from the Space
Telescope Science Institute, which is operated by the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS 5-03127. The authors acknowledge
the team led by co-PIs R. Maiolino and F. D’Eugenio for developing their observing
program with a zero-exclusive-access period.\r\n\r\nThis research is based on observations
made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope
Science Institute, which is operated by the Association of Universities for Research
in Astronomy, Inc., under NASA contract NAS 5–26555. These observations are associated
with program #15117.\r\n\r\nThe JWST and HST data presented in this article were
obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope
Science Institute. The specific observations analyzed can be accessed via doi:10.17909/ydwx-st06.\r\n\r\nThis
work is based in part on observations made with the Spitzer Space Telescope, which
was operated by the Jet Propulsion Laboratory, California Institute of Technology
under a contract with NASA. The Spitzer data used in this work can be found in doi:10.26131/IRSA3.\r\n\r\nThis
work was supported by the International Space Science Institute (ISSI) in Bern,
through ISSI International Team project #25-659 “Little Red Dots, Big Open Questions.”\r\n\r\nJWST
cartoon in Figure 6, credit: NASA.\r\n\r\nFacilities: VLT:Kueyen - Very Large Telescope
(Kueyen) (X-Shooter), VLT:Yepun (HAWK-I), JWST - James Webb Space Telescope (NIRCam,
NIRspec), HST - Hubble Space Telescope satellite (ACS), Spitzer - Spitzer Space
Telescope satellite (IRAC, MIPS) - .\r\n\r\nSoftware: astropy (Astropy Collaboration
et al. 2013, 2018; Astropy Collaboration et al. 2022), NumPy (C. R. Harris et al.
2020), SciPy (P. Virtanen et al. 2020), pysersic (I. Pasha & T. B. Miller 2023),
stpsf (M. D. Perrin et al. 2014), lmfit (M. Newville et al. 2014), EsoRex (ESO CPL
Development Team 2015), Claude (used for Python coding; https://claude.ai/), SEP
(K. Barbary 2016)."
date_created: 2026-07-12T22:02:17Z
date_published: 2026-07-10T00:00:00Z
date_updated: 2026-07-13T08:08:41Z
day: '10'
ddc:
- '520'
department:
- _id: JoMa
- _id: IlCa
- _id: GradSch
doi: 10.3847/2041-8213/ae7bfd
external_id:
arxiv:
- '2603.28335'
file:
- access_level: open_access
checksum: 7600db260d799ddea45cf3bd01effe41
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T07:46:22Z
date_updated: 2026-07-13T07:46:22Z
file_id: '22274'
file_name: 2026_AstrophysicalJourLetters_Torralba.pdf
file_size: 5419071
relation: main_file
success: 1
file_date_updated: 2026-07-13T07:46:22Z
fulldoi: https://doi.org/10.3847/2041-8213/ae7bfd
has_accepted_license: '1'
intvolume: ' 1005'
issue: '2'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: bd9b2118-d553-11ed-ba76-db24564edfea
grant_number: '101076224'
name: Young galaxies as tracers and agents of cosmic reionization
publication: The Astrophysical Journal Letters
publication_identifier:
eissn:
- 2041-8213
issn:
- 2041-8205
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: 'A black hole star at cosmic noon: Extreme Balmer break, photospheric continuum,
and broad absorption by thick winds in a Little Red Dot at z = 1.7'
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 1005
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '22264'
abstract:
- lang: eng
text: 'The correlation between galaxy stellar mass and gas-phase metallicity, known
as the mass–metallicity relation (MZR), gives key insights into the processes
that govern galaxy evolution. However, unquantified observational and selection
biases can result in systematic errors in attempts to recover the intrinsic MZR,
particularly at higher redshifts. We characterize the MZR at z ∼ 3–6 within a
fully Bayesian framework using JWST/NIRSpec spectra of 191 galaxies from the RUBIES
survey. We forward model the observed mass–metallicity surface using prospector-generated
spectra to account for two selection biases: the survey selection function and
the success in observing high signal-to-noise ratio emission lines. We demonstrate
that the RUBIES selection function, based on F444W magnitude and F150W – F444W
color, has a negligible effect on our measured MZR. A correct treatment of the
non-Gaussian metallicity uncertainties from strong-line calibrations lowers the
derived MZR normalization by 0.2 dex and flattens the slope by ∼20%; forward modeling
the effect of emission line observability steepens the slope by ∼15%. Both of
these biases must be taken into account in order to properly measure the intrinsic
MZR. This novel forward-modeling process motivates careful consideration of selection
functions in future surveys, and paves the way for robust, high-redshift chemical
enrichment studies that trace the evolution of the MZR across cosmic time.'
acknowledgement: "This work is based on observations made with the NASA/ESA/CSA James
Webb Space Telescope. The data were obtained from the Mikulski Archive for Space
Telescopes at the Space Telescope Science Institute, which is operated by the Association
of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127
for JWST. These observations are associated with program ID 4233. This material
is based upon work supported by the National Science Foundation Graduate Research
Fellowship under grant No. 2137424 as well as work supported by NASA under Award
No. 2025_3-0, issued through the Wisconsin Space Grant Consortium, and JWST-GO-4233.
Any opinions, findings, and conclusions or recommendations expressed in this material
are those of the author(s) and do not necessarily reflect the views of the National
Aeronautics and Space Administration. Support for program ID 4233 was provided by
NASA through a grant from the Space Telescope Science Institute, which is operated
by the Association of Universities for Research in Astronomy, Inc., under NASA contract
NAS 5-03127. M.V.M. is supported by the National Science Foundation via grant AAG
2205519. A.d.G. acknowledges support from a Clay Fellowship awarded by the Smithsonian
Astrophysical Observatory. T.B.M. was supported by a CIERA Fellowship. Part of the
computations for this research were performed on the Pennsylvania State University’s
Institute for Computational and Data Sciences’ Roar supercomputer. Some/all of the
data presented in this article were obtained from the Mikulski Archive for Space
Telescopes (MAST) at the Space Telescope Science Institute. The specific observations
analyzed can be accessed via doi:10.17909/qk5z-7p30. The scripts used to generate
the data and results in this work can be found in Zenodo at doi:10.5281/zenodo.20513668
and GitHub \r\nhttps://github.com/zachlewis99/rubies_mzr "
article_number: '159'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Zach
full_name: Lewis, Zach
last_name: Lewis
- first_name: Michael V.
full_name: Maseda, Michael V.
last_name: Maseda
- first_name: Anna
full_name: De Graaff, Anna
last_name: De Graaff
- first_name: Joel
full_name: Leja, Joel
last_name: Leja
- first_name: Bingjie
full_name: Wang, Bingjie
last_name: Wang
- first_name: Hans Walter
full_name: Rix, Hans Walter
last_name: Rix
- first_name: Ian
full_name: Mcconachie, Ian
last_name: Mcconachie
- first_name: Nikko J.
full_name: Cleri, Nikko J.
last_name: Cleri
- first_name: Rachel
full_name: Bezanson, Rachel
last_name: Bezanson
- first_name: Leindert A.
full_name: Boogaard, Leindert A.
last_name: Boogaard
- first_name: Gabriel
full_name: Brammer, Gabriel
last_name: Brammer
- first_name: Jenny E.
full_name: Greene, Jenny E.
last_name: Greene
- first_name: Michaela
full_name: Hirschmann, Michaela
last_name: Hirschmann
- first_name: Harley
full_name: Katz, Harley
last_name: Katz
- first_name: Ivo
full_name: Labbé, Ivo
last_name: Labbé
- first_name: Jorryt J
full_name: Matthee, Jorryt J
id: 7439a258-f3c0-11ec-9501-9df22fe06720
last_name: Matthee
orcid: 0000-0003-2871-127X
- first_name: Tim B.
full_name: Miller, Tim B.
last_name: Miller
- first_name: Rohan P.
full_name: Naidu, Rohan P.
last_name: Naidu
- first_name: Pascal A.
full_name: Oesch, Pascal A.
last_name: Oesch
- first_name: David J.
full_name: Setton, David J.
last_name: Setton
- first_name: Katherine A.
full_name: Suess, Katherine A.
last_name: Suess
- first_name: Andrea
full_name: Weibel, Andrea
last_name: Weibel
- first_name: Katherine E.
full_name: Whitaker, Katherine E.
last_name: Whitaker
- first_name: Christina C.
full_name: Williams, Christina C.
last_name: Williams
citation:
ama: Lewis Z, Maseda MV, De Graaff A, et al. The mass–metallicity relation and its
observational effects at z ∼ 3–6. The Astrophysical Journal. 2026;1005(2).
doi:10.3847/1538-4357/ae7bfc
apa: Lewis, Z., Maseda, M. V., De Graaff, A., Leja, J., Wang, B., Rix, H. W., …
Williams, C. C. (2026). The mass–metallicity relation and its observational effects
at z ∼ 3–6. The Astrophysical Journal. IOP Publishing. https://doi.org/10.3847/1538-4357/ae7bfc
chicago: Lewis, Zach, Michael V. Maseda, Anna De Graaff, Joel Leja, Bingjie Wang,
Hans Walter Rix, Ian Mcconachie, et al. “The Mass–Metallicity Relation and Its
Observational Effects at z ∼ 3–6.” The Astrophysical Journal. IOP Publishing,
2026. https://doi.org/10.3847/1538-4357/ae7bfc.
ieee: Z. Lewis et al., “The mass–metallicity relation and its observational
effects at z ∼ 3–6,” The Astrophysical Journal, vol. 1005, no. 2. IOP Publishing,
2026.
ista: Lewis Z, Maseda MV, De Graaff A, Leja J, Wang B, Rix HW, Mcconachie I, Cleri
NJ, Bezanson R, Boogaard LA, Brammer G, Greene JE, Hirschmann M, Katz H, Labbé
I, Matthee JJ, Miller TB, Naidu RP, Oesch PA, Setton DJ, Suess KA, Weibel A, Whitaker
KE, Williams CC. 2026. The mass–metallicity relation and its observational effects
at z ∼ 3–6. The Astrophysical Journal. 1005(2), 159.
mla: Lewis, Zach, et al. “The Mass–Metallicity Relation and Its Observational Effects
at z ∼ 3–6.” The Astrophysical Journal, vol. 1005, no. 2, 159, IOP Publishing,
2026, doi:10.3847/1538-4357/ae7bfc.
short: Z. Lewis, M.V. Maseda, A. De Graaff, J. Leja, B. Wang, H.W. Rix, I. Mcconachie,
N.J. Cleri, R. Bezanson, L.A. Boogaard, G. Brammer, J.E. Greene, M. Hirschmann,
H. Katz, I. Labbé, J.J. Matthee, T.B. Miller, R.P. Naidu, P.A. Oesch, D.J. Setton,
K.A. Suess, A. Weibel, K.E. Whitaker, C.C. Williams, The Astrophysical Journal
1005 (2026).
das_tickbox: '1'
dataavailabilitystatement: The specific observations analyzed can be accessed via
doi:10.17909/qk5z-7p30. The scripts used to generate the data and results in this
work can be found in Zenodo at doi:10.5281/zenodo.20513668 and GitHub https://github.com/zachlewis99/rubies_mzr
date_created: 2026-07-12T22:02:17Z
date_published: 2026-07-10T00:00:00Z
date_updated: 2026-07-13T07:40:41Z
day: '10'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.3847/1538-4357/ae7bfc
external_id:
arxiv:
- '2512.03134'
file:
- access_level: open_access
checksum: 9b13fbbc5e5e921c04676ebc532d9c42
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T07:35:16Z
date_updated: 2026-07-13T07:35:16Z
file_id: '22273'
file_name: 2026_AstrophysicalJour_Lewis.pdf
file_size: 1854628
relation: main_file
success: 1
file_date_updated: 2026-07-13T07:35:16Z
fulldoi: https://doi.org/10.3847/1538-4357/ae7bfc
has_accepted_license: '1'
intvolume: ' 1005'
issue: '2'
keyword:
- Galaxy evolution
- Chemical enrichment
- Metallicity
- Galaxy abundances
- Scaling relations
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
publication: The Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
- 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: no
title: The mass–metallicity relation and its observational effects at z ∼ 3–6
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 1005
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '22262'
abstract:
- lang: eng
text: Mixed modes are observed in many low-mass evolved stars. They provide information
about core rotation rates of these stars, which are lower than predicted by stellar
evolution models. The mixed modes themselves have been invoked as an angular momentum
(AM) transport mechanism, but estimating their transport efficiency requires knowledge
of their amplitudes. We constrain, for the first time, the mixed-mode amplitudes
in 2D hydrodynamical simulations of a 1.3M⊙ red giant using the code MUSIC. We
perform two simulations with outer radial truncations at fractional radii ro/r⋆
= 0.90 and 0.98. We compare the modes in the simulation with those found using
both GYRE and a Dedalus eigenvalue solver. Excellent frequency agreement is found
for all p-dominated modes, with minor discrepancies for g-dominated modes, especially
in the frequency range [60, 240] μHz. We find excellent eigenfunction agreement
for all modes except those in this frequency range. According to empirical predictions,
the largest kinetic energies are located around Vmax= 312.μHz, but in both simulations,
the modes with frequencies of ν < 50 μHz have the largest kinetic energies. In
the simulation with r/r⋆ = 0.98, the simulated modes have extrapolated surface
velocities comparable to the empirical predictions, with the highest surface velocities
in a bell-shaped curve peaking around ν = 700 μHz. The extrapolated surface velocities
of the low-frequency modes are small and thus hard to observe, but their large
kinetic energies deeper in the interior could significantly impact AM transport,
which has not yet been investigated.
acknowledgement: 'We would like to thank the referee for their careful reading of
the manuscript and their constructive comments that helped improve the paper. N.B.V.
would like to thank K. Belkacem and J. Philidet for helpful discussions. N.B.V.
is supported by STFC grant ST/Y002164/1. A.L.S. acknowledges support from the European
Research Council (ERC) under the Horizon Europe program (Synergy grant agreement
101071505: 4D-STAR) from the CNES SOHO-GOLF and PLATO grants at CEA-DAp, and from
ATPS (CNRS/INSU). Part of this work was supported by the ERC grant No. 787361-COBOM.
R.H.D.T. acknowledges support from NASA grants 80NSSC24K0895 and 80NSSC23K1517,
and NSF grant 2407636. A.L. is supported by ERC Starting Grant 101165631 (“Calcifer”).
The authors would like to acknowledge the use of the University of Exeter High-Performance
Computing (HPC) facility, ISCA, in carrying out this work. This work used the DiRAC
Memory Intensive service (Cosma8) at Durham University, managed by the Institute
for Computational Cosmology, and the DiRAC Data Intensive service (DIaL3) at the
University of Leicester, managed by the University of Leicester Research Computing
Service. These facilities are managed on behalf of the STFC DiRAC HPC (www.dirac.ac.uk).
The DiRAC services at Durham and Leicester were funded by BEIS, UKRI, and STFC capital
funding, and STFC operations grants. The service at Durham received funding from
Durham University. DiRAC is part of the UKRI Digital Research Infrastructure.'
article_number: '154'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Nils B.
full_name: De Vries, Nils B.
last_name: De Vries
- first_name: Arthur
full_name: Le Saux, Arthur
last_name: Le Saux
- first_name: Isabelle
full_name: Baraffe, Isabelle
last_name: Baraffe
- first_name: Thomas
full_name: Guillet, Thomas
last_name: Guillet
- first_name: Richard H.D.
full_name: Townsend, Richard H.D.
last_name: Townsend
- first_name: Armand
full_name: Leclerc, Armand
id: 2a1fb1fc-f373-11ef-901a-87cee43a1217
last_name: Leclerc
- first_name: Adrien
full_name: Morison, Adrien
last_name: Morison
citation:
ama: De Vries NB, Le Saux A, Baraffe I, et al. Revealing mixed modes in compressible
hydrodynamical simulations of red giant stars. The Astrophysical Journal.
2026;1005(2). doi:10.3847/1538-4357/ae7a3c
apa: De Vries, N. B., Le Saux, A., Baraffe, I., Guillet, T., Townsend, R. H. D.,
Leclerc, A., & Morison, A. (2026). Revealing mixed modes in compressible hydrodynamical
simulations of red giant stars. The Astrophysical Journal. IOP Publishing.
https://doi.org/10.3847/1538-4357/ae7a3c
chicago: De Vries, Nils B., Arthur Le Saux, Isabelle Baraffe, Thomas Guillet, Richard
H.D. Townsend, Armand Leclerc, and Adrien Morison. “Revealing Mixed Modes in Compressible
Hydrodynamical Simulations of Red Giant Stars.” The Astrophysical Journal.
IOP Publishing, 2026. https://doi.org/10.3847/1538-4357/ae7a3c.
ieee: N. B. De Vries et al., “Revealing mixed modes in compressible hydrodynamical
simulations of red giant stars,” The Astrophysical Journal, vol. 1005,
no. 2. IOP Publishing, 2026.
ista: De Vries NB, Le Saux A, Baraffe I, Guillet T, Townsend RHD, Leclerc A, Morison
A. 2026. Revealing mixed modes in compressible hydrodynamical simulations of red
giant stars. The Astrophysical Journal. 1005(2), 154.
mla: De Vries, Nils B., et al. “Revealing Mixed Modes in Compressible Hydrodynamical
Simulations of Red Giant Stars.” The Astrophysical Journal, vol. 1005,
no. 2, 154, IOP Publishing, 2026, doi:10.3847/1538-4357/ae7a3c.
short: N.B. De Vries, A. Le Saux, I. Baraffe, T. Guillet, R.H.D. Townsend, A. Leclerc,
A. Morison, The Astrophysical Journal 1005 (2026).
das_tickbox: '1'
dataavailabilitystatement: The kinetic energies and surface velocities shown in Figure
4, as well as the underlying spectral data of this work, can be found in a Zenodo
repository at doi:10.5281/zenodo.18661976.
date_created: 2026-07-12T22:02:17Z
date_published: 2026-07-10T00:00:00Z
date_updated: 2026-07-13T08:16:25Z
day: '10'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.3847/1538-4357/ae7a3c
external_id:
arxiv:
- '2606.07125'
file:
- access_level: open_access
checksum: d32061d2341bac3adeb404975c6bd59e
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T08:14:01Z
date_updated: 2026-07-13T08:14:01Z
file_id: '22275'
file_name: 2026_AstrophysicalJour_deVries.pdf
file_size: 14866194
relation: main_file
success: 1
file_date_updated: 2026-07-13T08:14:01Z
fulldoi: https://doi.org/10.3847/1538-4357/ae7a3c
has_accepted_license: '1'
intvolume: ' 1005'
issue: '2'
keyword:
- Stellar physics
- Stellar interiors
- Asteroseismology
- Stellar oscillations
- Hydrodynamical simulations
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 914d8549-16d5-11f0-9cad-bbe6324c93a9
grant_number: '101165631'
name: 'Unveiling the mysteries of stellar dynamics: a pioneering journey in magnetoasteroseismology'
publication: The Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
- 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Revealing mixed modes in compressible hydrodynamical simulations of red giant
stars
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 1005
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '22261'
abstract:
- lang: eng
text: 'Climate change is significantly altering regional precipitation patterns
across Europe and the Mediterranean. We analyze daily precipitation distribution
changes in a 15-member Euro-CORDEX ensemble, through a diagnostic framework that
separates occurrence changes, wet-days intensity shifts and distortions. At +4
∘C global warming, Northern Europe shows a robust intensification of precipitation,
driven by both higher occurrence and stronger events. Conversely, the Mediterranean
exhibits a dominant drying signal, primarily due to fewer wet-days, which impacts
daily precipitation distribution even for heavy rainfall. Transitional zones in
the northern Mediterranean reveal “U-shape” regimes, with rising extremes but
declining moderate rain. Comparing with ERA5 reanalysis over the past, low model
agreement in the south highlights higher uncertainty in the Mediterranean region.
The timing of robust signal emergence varies: Northern Europe shows robust patterns
from +1 ∘C, while the Mediterranean exhibits delays until +3-4 ∘C. These findings
are essential for informing risk-based adaptation strategies.'
acknowledgement: J.A. gratefully acknowledges the JSPS postdoctoral fellowship (Japan
Society for Promotion of Science, grant number P25709). C.J.M. gratefully acknowledges
funding from the European Research Council (ERC) under the European Union’s Horizon
2020 research and innovation program (Project CLUSTER, Grant Agreement No. 805041).
The authors also thank Samuel Somot (Centre National de Recherches Météorologiques,
Toulouse) and Juliette Blanchet (Institut des Géosciences de l’Environnement, Grenoble)
for their fruitful discussions on the project.
article_number: '572'
article_processing_charge: Yes
article_type: original
author:
- first_name: Julie
full_name: André, Julie
last_name: André
- first_name: Nicolas
full_name: Chiabrando, Nicolas
last_name: Chiabrando
- first_name: Caroline J
full_name: Muller, Caroline J
id: f978ccb0-3f7f-11eb-b193-b0e2bd13182b
last_name: Muller
orcid: 0000-0001-5836-5350
- first_name: Philippe
full_name: Drobinski, Philippe
last_name: Drobinski
- first_name: Fabio
full_name: D’Andrea, Fabio
last_name: D’Andrea
citation:
ama: André J, Chiabrando N, Muller CJ, Drobinski P, D’Andrea F. Distinct regimes
of precipitation changes across Europe and the Mediterranean under global warming.
Communications Earth and Environment. 2026;7. doi:10.1038/s43247-026-03519-7
apa: André, J., Chiabrando, N., Muller, C. J., Drobinski, P., & D’Andrea, F.
(2026). Distinct regimes of precipitation changes across Europe and the Mediterranean
under global warming. Communications Earth and Environment. Springer Nature.
https://doi.org/10.1038/s43247-026-03519-7
chicago: André, Julie, Nicolas Chiabrando, Caroline J Muller, Philippe Drobinski,
and Fabio D’Andrea. “Distinct Regimes of Precipitation Changes across Europe and
the Mediterranean under Global Warming.” Communications Earth and Environment.
Springer Nature, 2026. https://doi.org/10.1038/s43247-026-03519-7.
ieee: J. André, N. Chiabrando, C. J. Muller, P. Drobinski, and F. D’Andrea, “Distinct
regimes of precipitation changes across Europe and the Mediterranean under global
warming,” Communications Earth and Environment, vol. 7. Springer Nature,
2026.
ista: André J, Chiabrando N, Muller CJ, Drobinski P, D’Andrea F. 2026. Distinct
regimes of precipitation changes across Europe and the Mediterranean under global
warming. Communications Earth and Environment. 7, 572.
mla: André, Julie, et al. “Distinct Regimes of Precipitation Changes across Europe
and the Mediterranean under Global Warming.” Communications Earth and Environment,
vol. 7, 572, Springer Nature, 2026, doi:10.1038/s43247-026-03519-7.
short: J. André, N. Chiabrando, C.J. Muller, P. Drobinski, F. D’Andrea, Communications
Earth and Environment 7 (2026).
das_tickbox: '1'
dataavailabilitystatement: ERA5 reanalysis and Euro-CORDEX simulations are publicly
available from https://doi.org/10.24381/cds.143582cf and https://cordex.org/data-access/esgf/.
The custom code developed and used for this paper can be accessed through Zenodo,
https://doi.org/10.5281/zenodo.18995401.
date_created: 2026-07-12T22:02:16Z
date_published: 2026-07-06T00:00:00Z
date_updated: 2026-07-13T07:13:21Z
day: '06'
ddc:
- '550'
department:
- _id: CaMu
doi: 10.1038/s43247-026-03519-7
ec_funded: 1
file:
- access_level: open_access
checksum: fd8f57cbe180f7a4d49ab17b3571ad2b
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T07:12:35Z
date_updated: 2026-07-13T07:12:35Z
file_id: '22272'
file_name: 2026_CommEarthEnvironment_Andre.pdf
file_size: 3870924
relation: main_file
success: 1
file_date_updated: 2026-07-13T07:12:35Z
fulldoi: https://doi.org/10.1038/s43247-026-03519-7
has_accepted_license: '1'
intvolume: ' 7'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 629205d8-2b32-11ec-9570-e1356ff73576
call_identifier: H2020
grant_number: '805041'
name: Organization of CLoUdS, and implications of Tropical cyclones and for the
Energetics of the tropics, in current and waRming climate
publication: Communications Earth and Environment
publication_identifier:
eissn:
- 2662-4435
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Distinct regimes of precipitation changes across Europe and the Mediterranean
under global warming
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 7
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '22270'
abstract:
- lang: eng
text: "The explosion of a white dwarf (WD) in a close binary can launch a surviving
runaway star at\r\nvelocities of ≳ 1000 km s−1\r\n. Such runaways provide a direct
probe of thermonuclear supernovae (SNe)\r\nin double-degenerate binaries. Several
candidate runaways are known, but their evolutionary states\r\nand the demographics
of the broader population are uncertain. To enable robust population inference,\r\nwe
carry out a systematic survey for hypervelocity runaways with a simple selection
function, selecting\r\ncandidates based on large Gaia-inferred tangential velocities
and blue colors. We classify 100% of the\r\nresulting 92 candidates using a combination
of spectroscopic follow-up and archival data. The search\r\nyields ten suspected
D6\r\nstars and three LP 40-365 stars. Three D6\r\nstars are new discoveries,
including\r\ntwo hot (Teff ≳ 50,000 K) objects and one cool (Teff ≈ 7,000 K) object.
We forward-model our survey\r\nunder several proposed D6\r\nstar evolutionary
models, coupling each to a Galactic model and the survey\r\nselection function.
No single model reproduces the observed diversity of D6\r\nstars, which likely
reflects\r\na range of remnant masses, ages, and heating mechanisms. Models in
which runaway companions\r\nare heated by SN shocks alone are too faint and short-lived
to explain most of the observed sample,\r\nwhile fully reheated models are too
luminous and long-lived. Models with intermediate heating,\r\nas occurs in some
simulations of violent mergers and partially disrupted remnants, best match the\r\nobserved
magnitude, distance, and kinematic-age distributions. The inferred D6\r\nstar
birth rate is\r\nmodel dependent, but the models that best match the observed
population require rates of only a\r\nfew percent of the Galactic SN Ia rate,
perhaps implying that most SNe Ia result from WD binaries\r\nin which both components
explode. If most SNe Ia do produce surviving runaways, these must be\r\nfainter
or shorter-lived than the currently known runaways."
acknowledgement: "We thank Lars Bildsten, Evan Bauer, Ruediger Pakmor, Jim Fuller,
Logan Proust, Abinaya Rajamuthukumar, and Stephan Geier for useful discussion related
to\r\nthis work.\r\nThis work was supported by NSF grants AST-2508988\r\nand AST-2205631,
NASA/ESA Hubble Space Telescope\r\nprogram No. 17441, and Scialog grant #SA-LSST-2024-\r\n114c
from the Research Corporation for Science Advancement. The Kavli Institute for Theoretical
Physics\r\n(KITP) hosted the program, “White Dwarfs as Probes of\r\nthe Evolution
of Planets, Stars, the Milky Way, and the\r\nExpanding Universe,” during which this
project was initiated. This research was supported in part by the U.S.\r\nNational
Science Foundation (NSF) under grants PHY1748958. This research benefited from discussions
that\r\nwere funded by the Gordon and Betty Moore Foundation\r\nthrough Grant GBMF5076.\r\nWe
thank the staffs of the various observatories at\r\nwhich data were obtained. This
work is partially based\r\non observations obtained at the Southern Astrophysical
Research (SOAR) telescope, which is a joint project\r\nof the Minist´erio da Ciˆencia,
Tecnologia e Inova¸c˜oes\r\n(MCTI/LNA) do Brasil, the US National Science Foundation’s
NOIRLab, the University of North Carolina\r\nat Chapel Hill (UNC), and Michigan
State University\r\n(MSU). Some of the data presented herein were obtained\r\nat
the W. M. Keck Observatory, which is operated as a\r\nscientific partnership among
the California Institute of\r\nTechnology, the University of California, and NASA;
the observatory was made possible by the generous financial\r\nsupport of the W.
M. Keck Foundation.\r\nThis research has made use of the Keck Observatory\r\nArchive
(KOA), which is operated by the W. M. Keck\r\nObservatory and the NASA Exoplanet
Science Institute\r\n(NExScI), under contract with the National Aeronautics\r\nand
Space Administration.\r\nThis work has made use of data from the\r\nEuropean Space
Agency (ESA) mission Gaia\r\n(https://www.cosmos.esa.int/gaia), processed\r\nby
the Gaia Data Processing and Analysis Consortium\r\n(DPAC, https://www.cosmos.esa.int/web/gaia/\r\ndpac/consortium).
Funding for the DPAC has been\r\nprovided by national institutions, in particular
the\r\ninstitutions participating in the Gaia Multilateral\r\nAgreement."
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Kareem
full_name: El-Badry, Kareem
last_name: El-Badry
- first_name: Klaus
full_name: Werner, Klaus
last_name: Werner
- first_name: Ken J.
full_name: Shen, Ken J.
last_name: Shen
- first_name: Jay
full_name: Strader, Jay
last_name: Strader
- first_name: Antonio C.
full_name: Rodriguez, Antonio C.
last_name: Rodriguez
- first_name: Jiwon Jesse
full_name: Han, Jiwon Jesse
last_name: Han
- first_name: Vedant
full_name: Chandra, Vedant
last_name: Chandra
- first_name: Laura
full_name: Chomiuk, Laura
last_name: Chomiuk
- first_name: Zachary P.
full_name: Vanderbosch, Zachary P.
last_name: Vanderbosch
- first_name: Lisa
full_name: Blomberg, Lisa
last_name: Blomberg
- first_name: Natsuko
full_name: Yamaguchi, Natsuko
last_name: Yamaguchi
- first_name: Pranav
full_name: Nagarajan, Pranav
last_name: Nagarajan
- first_name: Ilaria
full_name: Caiazzo, Ilaria
id: 8ae5b6e7-2a03-11ee-914d-b58ed7a3b47d
last_name: Caiazzo
orcid: 0000-0002-4770-5388
- first_name: Joannes C
full_name: van Roestel, Joannes C
id: 4d122fc8-6083-11f0-87a5-97d68b860333
last_name: van Roestel
- first_name: Hila
full_name: Glanz, Hila
last_name: Glanz
- first_name: Tin Long Sunny
full_name: Wong, Tin Long Sunny
last_name: Wong
- first_name: Aakash
full_name: Bhat, Aakash
last_name: Bhat
- first_name: Mark A.
full_name: Hollands, Mark A.
last_name: Hollands
citation:
ama: El-Badry K, Werner K, Shen KJ, et al. A systematic survey for hypervelocity
runaways from thermonuclear supernovae. The Open Journal of Astrophysics.
2026;9. doi:10.33232/001c.164326
apa: El-Badry, K., Werner, K., Shen, K. J., Strader, J., Rodriguez, A. C., Han,
J. J., … Hollands, M. A. (2026). A systematic survey for hypervelocity runaways
from thermonuclear supernovae. The Open Journal of Astrophysics. Maynooth
Academic Publishing. https://doi.org/10.33232/001c.164326
chicago: El-Badry, Kareem, Klaus Werner, Ken J. Shen, Jay Strader, Antonio C. Rodriguez,
Jiwon Jesse Han, Vedant Chandra, et al. “A Systematic Survey for Hypervelocity
Runaways from Thermonuclear Supernovae.” The Open Journal of Astrophysics.
Maynooth Academic Publishing, 2026. https://doi.org/10.33232/001c.164326.
ieee: K. El-Badry et al., “A systematic survey for hypervelocity runaways
from thermonuclear supernovae,” The Open Journal of Astrophysics, vol.
9. Maynooth Academic Publishing, 2026.
ista: El-Badry K, Werner K, Shen KJ, Strader J, Rodriguez AC, Han JJ, Chandra V,
Chomiuk L, Vanderbosch ZP, Blomberg L, Yamaguchi N, Nagarajan P, Caiazzo I, van
Roestel JC, Glanz H, Wong TLS, Bhat A, Hollands MA. 2026. A systematic survey
for hypervelocity runaways from thermonuclear supernovae. The Open Journal of
Astrophysics. 9.
mla: El-Badry, Kareem, et al. “A Systematic Survey for Hypervelocity Runaways from
Thermonuclear Supernovae.” The Open Journal of Astrophysics, vol. 9, Maynooth
Academic Publishing, 2026, doi:10.33232/001c.164326.
short: K. El-Badry, K. Werner, K.J. Shen, J. Strader, A.C. Rodriguez, J.J. Han,
V. Chandra, L. Chomiuk, Z.P. Vanderbosch, L. Blomberg, N. Yamaguchi, P. Nagarajan,
I. Caiazzo, J.C. van Roestel, H. Glanz, T.L.S. Wong, A. Bhat, M.A. Hollands, The
Open Journal of Astrophysics 9 (2026).
das_tickbox: '1'
dataavailabilitystatement: "We thank the staffs of the various observatories at\r\nwhich
data were obtained. This work is partially based\r\non observations obtained at
the Southern Astrophysical Research (SOAR) telescope, which is a joint project\r\nof
the Minist´erio da Ciˆencia, Tecnologia e Inova¸c˜oes\r\n(MCTI/LNA) do Brasil, the
US National Science Foundation’s NOIRLab, the University of North Carolina\r\nat
Chapel Hill (UNC), and Michigan State University\r\n(MSU). Some of the data presented
herein were obtained\r\nat the W. M. Keck Observatory, which is operated as a\r\nscientific
partnership among the California Institute of\r\nTechnology, the University of California,
and NASA; the\r\nobservatory was made possible by the generous financial\r\nsupport
of the W. M. Keck Foundation.\r\nThis research has made use of the Keck Observatory\r\nArchive
(KOA), which is operated by the W. M. Keck\r\nObservatory and the NASA Exoplanet
Science Institute\r\n(NExScI), under contract with the National Aeronautics\r\nand
Space Administration.\r\nThis work has made use of data from the\r\nEuropean Space
Agency (ESA) mission Gaia\r\n(https://www.cosmos.esa.int/gaia), processed\r\nby
the Gaia Data Processing and Analysis Consortium\r\n(DPAC, https://www.cosmos.esa.int/web/gaia/\r\ndpac/consortium).
Funding for the DPAC has been\r\nprovided by national institutions, in particular
the\r\ninstitutions participating in the Gaia Multilateral\r\nAgreement."
date_created: 2026-07-12T22:02:19Z
date_published: 2026-06-30T00:00:00Z
date_updated: 2026-07-13T09:09:34Z
day: '30'
ddc:
- '520'
department:
- _id: IlCa
doi: 10.33232/001c.164326
external_id:
arxiv:
- '2606.11293'
file:
- access_level: open_access
checksum: 6320fd19e5ea3399f332be5aab022736
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T09:05:36Z
date_updated: 2026-07-13T09:05:36Z
file_id: '22282'
file_name: 2026_OpenJourAstrophysics_ElBadry.pdf
file_size: 1994596
relation: main_file
success: 1
file_date_updated: 2026-07-13T09:05:36Z
fulldoi: https://doi.org/10.33232/001c.164326
has_accepted_license: '1'
intvolume: ' 9'
keyword:
- white dwarfs
- 'binaries: close'
- 'stars: chemically peculiar'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: The Open Journal of Astrophysics
publication_identifier:
eissn:
- 2565-6120
publication_status: published
publisher: Maynooth Academic Publishing
quality_controlled: '1'
researchdata_availability: no
scopus_import: '1'
status: public
supplementarymaterial: no
title: A systematic survey for hypervelocity runaways from thermonuclear supernovae
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 9
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
_id: '22269'
abstract:
- lang: eng
text: The divisome apparatus synthesizes septal peptidoglycan (PG) during bacterial
division. In Escherichia coli, the class A penicillin-binding protein (aPBP) called
PBP1b has been implicated in division, but its role in the process has remained
unclear. Here we show using in situ cryo-electron tomography, genetics and other
imaging methods that PBP1b is required to produce a wedge-like density of PG at
the division site and that loss of this structure weakens the division site, making
it hypersusceptible to osmotic lysis. Surprisingly, the activator LpoB needed
for general PBP1b function was not required for its role in division. Of the two
PBP1b isoforms produced in cells, we show that the one with an extended cytoplasmic
N terminus localizes to and functions at the division site, probably via recruitment
by the FtsA component of the divisome. The conservation of aPBPs with extended
cytoplasmic N termini suggests that other Gram-negative bacteria may use similar
mechanisms for division site reinforcement.
acknowledgement: We thank all members of the Bernhardt, Rudner, Navarro and Vettiger
Laboratories for support and helpful conversations. We thank C. Genoud, J. Daraspe,
A. Mucciolo and D. de Bellis at the Electron Microscopy Facility of the University
of Lausanne and E. Jeanvoine for providing access to workstations for cryo-ET image
processing; S. Sterling, C. Borsa, J. Podgorski, P. Vinh Dip, E. Brignole and A.
Osherov at the MIT.nano cryo-EM facility, K. Song and C. Xu at the University of
Massachusetts cryo-EM facility, and R. Walsh and Z. Li at the cryo-EM at Harvard
Medical School facility for providing access to the cryo-EM microscopes and for
all their help, advice and maintenance of cryo-EM equipment. AFM was performed at
the Harvard University Center for Nanoscale Systems (CNS), a member of the National
Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by
the National Science Foundation under NSF award no. ECCS-2025158. We thank N. S.
Colella for excellent advice on AFM data acquisition and analysis; the MicRoN imaging
core at Harvard Medical School for excellent advice on live cell imaging and maintenance
of fluorescence microscopes; B. Krautz for creating the cartoon illustrations (www.sciencecommunicated.com);
and L. Miles and R. Aeschimann for assistance with strain construction. A.V. was
supported by an EMBO long-term postdoctoral fellowship ALTF_89-2019, the Swiss National
Science Foundation (SNSF) Postdoc.Mobility fellowship P500PB_203143. P.P.N. was
a recipient of early postdoc.mobility and postdoc.mobility fellowships (P2BSP3_188112
and P400PB_199252). This work was also supported by funding from the National Institutes
of Health (R35GM142553 to L.H.C. and R01AI083365 to T.G.B.), investigator funds
from the Howard Hughes Medical Institute (T.G.B.), an SNSF project grant (320030-236243
to A.V.), an SNSF Starting Grant (TMSGI3_218251 to P.P.N.), an SNSF Project grant
(320030-236069 to P.P.N), an SNSF SPARK grant (CRSK-3_237167 to P.P.N.), cryo-EM
funds from the Faculty of Biology and Medicine at University of Lausanne to P.P.N.
and the Foundation Pierre Mercier pour la Science (to P.P.N.).
article_processing_charge: Yes (in subscription journal)
article_type: original
author:
- first_name: Paula P.
full_name: Navarro, Paula P.
last_name: Navarro
- first_name: Andrea
full_name: Vettiger, Andrea
last_name: Vettiger
- first_name: Roman
full_name: Hajdu, Roman
id: ffab949d-133f-11ed-8f02-94de21ace503
last_name: Hajdu
- first_name: Virly Y.
full_name: Ananda, Virly Y.
last_name: Ananda
- first_name: Alejandro
full_name: López-Tavares, Alejandro
last_name: López-Tavares
- first_name: Ernst W.
full_name: Schmid, Ernst W.
last_name: Schmid
- first_name: Johannes C.
full_name: Walter, Johannes C.
last_name: Walter
- first_name: Martin
full_name: Loose, Martin
id: 462D4284-F248-11E8-B48F-1D18A9856A87
last_name: Loose
orcid: 0000-0001-7309-9724
- first_name: Luke H.
full_name: Chao, Luke H.
last_name: Chao
- first_name: Thomas G.
full_name: Bernhardt, Thomas G.
last_name: Bernhardt
citation:
ama: Navarro PP, Vettiger A, Hajdu R, et al. The penicillin-binding protein PBP1b
fortifies the Escherichia coli division site against osmotic rupture. Nature
Microbiology. 2026. doi:10.1038/s41564-026-02403-6
apa: Navarro, P. P., Vettiger, A., Hajdu, R., Ananda, V. Y., López-Tavares, A.,
Schmid, E. W., … Bernhardt, T. G. (2026). The penicillin-binding protein PBP1b
fortifies the Escherichia coli division site against osmotic rupture. Nature
Microbiology. Springer Nature. https://doi.org/10.1038/s41564-026-02403-6
chicago: Navarro, Paula P., Andrea Vettiger, Roman Hajdu, Virly Y. Ananda, Alejandro
López-Tavares, Ernst W. Schmid, Johannes C. Walter, Martin Loose, Luke H. Chao,
and Thomas G. Bernhardt. “The Penicillin-Binding Protein PBP1b Fortifies the Escherichia
Coli Division Site against Osmotic Rupture.” Nature Microbiology. Springer
Nature, 2026. https://doi.org/10.1038/s41564-026-02403-6.
ieee: P. P. Navarro et al., “The penicillin-binding protein PBP1b fortifies
the Escherichia coli division site against osmotic rupture,” Nature Microbiology.
Springer Nature, 2026.
ista: Navarro PP, Vettiger A, Hajdu R, Ananda VY, López-Tavares A, Schmid EW, Walter
JC, Loose M, Chao LH, Bernhardt TG. 2026. The penicillin-binding protein PBP1b
fortifies the Escherichia coli division site against osmotic rupture. Nature Microbiology.
mla: Navarro, Paula P., et al. “The Penicillin-Binding Protein PBP1b Fortifies the
Escherichia Coli Division Site against Osmotic Rupture.” Nature Microbiology,
Springer Nature, 2026, doi:10.1038/s41564-026-02403-6.
short: P.P. Navarro, A. Vettiger, R. Hajdu, V.Y. Ananda, A. López-Tavares, E.W.
Schmid, J.C. Walter, M. Loose, L.H. Chao, T.G. Bernhardt, Nature Microbiology
(2026).
das_tickbox: '1'
dataavailabilitystatement: 'The data, plasmids and strains that support the findings
of this study are available from the corresponding authors by request. Representative
tomograms are deposited in EMDB: EMD-27479 (wild-type), EMD-53351 (∆ponB), EMD-53357(∆lpoB)
and EMD-53363 (∆ponA). Corresponding raw movie frames and stacks of tilt series
are deposited as EMPIAR-11090 (wild type), EMPIAR-13502 (∆ponB), EMPIAR-13513 (∆lpoB)
and EMPIAR-13512 (∆ponA), and will be released upon publication. Other data related
to this manuscript (for example, AFM, light microscopy, growth curves and so on)
can be found on Zenodo at https://doi.org/10.5281/zenodo.20841819 (ref. 101). Source
data are provided with this paper. Scripts used in this study were deposited on
GitHub at https://github.com/NavarroVettiger/Navarro-et-al_2022 and https://github.com/virlyananda/EM-ImageProcessing.'
date_created: 2026-07-12T22:02:19Z
date_published: 2026-07-03T00:00:00Z
date_updated: 2026-07-13T09:22:49Z
day: '03'
ddc:
- '570'
department:
- _id: MaLo
- _id: GradSch
doi: 10.1038/s41564-026-02403-6
external_id:
pmid:
- '42399561'
fulldoi: https://doi.org/10.1038/s41564-026-02403-6
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1038/s41564-026-02403-6
month: '07'
oa: 1
oa_version: Published Version
pmid: 1
publication: Nature Microbiology
publication_identifier:
eissn:
- 2058-5276
publication_status: epub_ahead
publisher: Springer Nature
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: The penicillin-binding protein PBP1b fortifies the Escherichia coli division
site against osmotic rupture
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '22288'
abstract:
- lang: eng
text: Soft solids and their surface deformations control the response of many natural
and artificial systems. Yet, their underlying properties are vigorously debated,
particularly for polymer networks. While molecular-scale theories predict no interfacial
changes with macroscopic deformation, multiple experiments suggest otherwise.
To settle this issue, we measure displacement fields near the interface of a silicone
gel, in the limit of small deformations. We discover an unexpected multiscale
response. The shear modulus decreases smoothly by half with 20 μm of the interface.
At the same time we observe a surface excess elasticity, that depends on history
and outer medium composition. These results reveal the fundamentally multiscale
nature of polymeric surfaces, and call for further experimental and theoretical
investigations into the basic understanding of soft solid interfaces.
acknowledgement: The authors thank Katharine Jensen, Stefanie Heyden, Thomas Salez,
Francesco Stellacci, Denis Bartolo, Francesco Picella, Hélène Delanoë-Ayari, Mathieu
Leocmach, Antoine Bérut, Cécile Cottin-Bizonne, Anne-Laure Biance, and Oriane Talabart
for useful discussions. We also thank the reviewers for excellent suggestions that
substantively improved the manuscript.
article_number: '021063'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Nicolas
full_name: Bain, Nicolas
last_name: Bain
- first_name: Lawrence A.
full_name: Wilen, Lawrence A.
last_name: Wilen
- first_name: Dominic
full_name: Gerber, Dominic
last_name: Gerber
- first_name: Mengjie
full_name: Zu, Mengjie
id: 26dd9e7c-e86a-11eb-a854-82ac731c9ae2
last_name: Zu
- first_name: Carl Peter
full_name: Goodrich, Carl Peter
id: EB352CD2-F68A-11E9-89C5-A432E6697425
last_name: Goodrich
orcid: 0000-0002-1307-5074
- first_name: Senthilkumar
full_name: Duraivel, Senthilkumar
last_name: Duraivel
- first_name: Kaarthik
full_name: Varma, Kaarthik
last_name: Varma
- first_name: Harsha
full_name: Koganti, Harsha
last_name: Koganti
- first_name: Robert W.
full_name: Style, Robert W.
last_name: Style
- first_name: Eric R.
full_name: Dufresne, Eric R.
last_name: Dufresne
citation:
ama: Bain N, Wilen LA, Gerber D, et al. Multiscale interfacial mechanics of soft
solids. Physical Review X. 2026;16(2). doi:10.1103/8msx-l8s7
apa: Bain, N., Wilen, L. A., Gerber, D., Zu, M., Goodrich, C. P., Duraivel, S.,
… Dufresne, E. R. (2026). Multiscale interfacial mechanics of soft solids. Physical
Review X. American Physical Society. https://doi.org/10.1103/8msx-l8s7
chicago: Bain, Nicolas, Lawrence A. Wilen, Dominic Gerber, Mengjie Zu, Carl Peter
Goodrich, Senthilkumar Duraivel, Kaarthik Varma, Harsha Koganti, Robert W. Style,
and Eric R. Dufresne. “Multiscale Interfacial Mechanics of Soft Solids.” Physical
Review X. American Physical Society, 2026. https://doi.org/10.1103/8msx-l8s7.
ieee: N. Bain et al., “Multiscale interfacial mechanics of soft solids,”
Physical Review X, vol. 16, no. 2. American Physical Society, 2026.
ista: Bain N, Wilen LA, Gerber D, Zu M, Goodrich CP, Duraivel S, Varma K, Koganti
H, Style RW, Dufresne ER. 2026. Multiscale interfacial mechanics of soft solids.
Physical Review X. 16(2), 021063.
mla: Bain, Nicolas, et al. “Multiscale Interfacial Mechanics of Soft Solids.” Physical
Review X, vol. 16, no. 2, 021063, American Physical Society, 2026, doi:10.1103/8msx-l8s7.
short: N. Bain, L.A. Wilen, D. Gerber, M. Zu, C.P. Goodrich, S. Duraivel, K. Varma,
H. Koganti, R.W. Style, E.R. Dufresne, Physical Review X 16 (2026).
das_tickbox: '1'
dataavailabilitystatement: The data that support the findings of this article are
openly available https://github.com/nicobain/Multiscale_interfacial_mechanics_soft_solids_data
date_created: 2026-07-13T09:40:54Z
date_published: 2026-06-30T00:00:00Z
date_updated: 2026-07-13T11:17:51Z
day: '30'
ddc:
- '530'
department:
- _id: CaGo
doi: 10.1103/8msx-l8s7
external_id:
arxiv:
- '2410.09158'
file:
- access_level: open_access
checksum: 47354f40981223fb0c9afe292f16ead1
content_type: application/pdf
creator: dernst
date_created: 2026-07-13T11:16:47Z
date_updated: 2026-07-13T11:16:47Z
file_id: '22309'
file_name: 2026_PhysicalReviewX_Bain.pdf
file_size: 4367284
relation: main_file
success: 1
file_date_updated: 2026-07-13T11:16:47Z
fulldoi: https://doi.org/10.1103/8msx-l8s7
has_accepted_license: '1'
intvolume: ' 16'
issue: '2'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: Physical Review X
publication_identifier:
issn:
- 2160-3308
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Multiscale interfacial mechanics of soft solids
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 16
year: '2026'
...
---
OA_type: closed access
_id: '22286'
abstract:
- lang: eng
text: Plants are remarkable organisms. Unlike animals, they cannot flee and, rooted
in one place, they must cope with whatever challenges arise — nutrient scarcity,
drought, shade, wind or obstacles in the soil. Their extraordinary ability to
survive in such unstable environmental conditions lies in their capacity to adapt.
In response to environmental signals, plants can rapidly adjust the rate of organ
growth, change the direction of growth, bend toward resources, or remodel their
body architecture by promoting or suppressing the formation of new organs such
as lateral roots, branches, leaves, or flowers. This unique developmental plasticity
depends on chemical signals, plant hormones that serve as regulators and coordinators
of endogenous molecular and cellular processes. Chief among these signals is auxin,
a plant hormone central to nearly every aspect of plant life.
article_processing_charge: No
article_type: original
author:
- first_name: Valentin
full_name: Leitner, Valentin
id: 4c665ce3-0016-11ec-bea0-e44de7a4fa3d
last_name: Leitner
- first_name: Eva
full_name: Benková, Eva
id: 38F4F166-F248-11E8-B48F-1D18A9856A87
last_name: Benková
orcid: 0000-0002-8510-9739
citation:
ama: Leitner V, Benková E. Auxin and the control of plant growth and development.
Current Biology. 2026;36(13):R739-R744. doi:10.1016/j.cub.2026.04.047
apa: Leitner, V., & Benková, E. (2026). Auxin and the control of plant growth
and development. Current Biology. Elsevier. https://doi.org/10.1016/j.cub.2026.04.047
chicago: Leitner, Valentin, and Eva Benková. “Auxin and the Control of Plant Growth
and Development.” Current Biology. Elsevier, 2026. https://doi.org/10.1016/j.cub.2026.04.047.
ieee: V. Leitner and E. Benková, “Auxin and the control of plant growth and development,”
Current Biology, vol. 36, no. 13. Elsevier, pp. R739–R744, 2026.
ista: Leitner V, Benková E. 2026. Auxin and the control of plant growth and development.
Current Biology. 36(13), R739–R744.
mla: Leitner, Valentin, and Eva Benková. “Auxin and the Control of Plant Growth
and Development.” Current Biology, vol. 36, no. 13, Elsevier, 2026, pp.
R739–44, doi:10.1016/j.cub.2026.04.047.
short: V. Leitner, E. Benková, Current Biology 36 (2026) R739–R744.
corr_author: '1'
das_tickbox: '0'
date_created: 2026-07-13T09:39:40Z
date_published: 2026-07-06T00:00:00Z
date_updated: 2026-07-13T11:11:56Z
day: '06'
department:
- _id: EvBe
- _id: GradSch
doi: 10.1016/j.cub.2026.04.047
external_id:
pmid:
- '42407441'
fulldoi: https://doi.org/10.1016/j.cub.2026.04.047
intvolume: ' 36'
issue: '13'
language:
- iso: eng
month: '07'
oa_version: None
page: R739-R744
pmid: 1
publication: Current Biology
publication_identifier:
issn:
- 0960-9822
publication_status: published
publisher: Elsevier
quality_controlled: '1'
researchdata_availability: no
scopus_import: '1'
status: public
supplementarymaterial: no
title: Auxin and the control of plant growth and development
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 36
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '22291'
abstract:
- lang: eng
text: Persistent homology is a fundamental tool in Topological Data Analysis. The
associated algebraic structure is the persistence module, a sequence of vector
spaces connected by linear maps. Persistence modules admit a complete and fast-to-compute
invariant known as the persistence diagram. However, this is no longer the case
for maps between persistence modules (i.e. persistence maps). We propose a new
invariant for persistence maps, consisting of a partial matching between the persistence
diagrams of the domain and codomain modules. We show that this invariant is additive
with respect to the direct sum decomposition of persistence maps, is more discriminative
than the image module, and is computable in cubic time. Furthermore, we provide
an implementation and demonstrate its efficiency by integrating it with edge collapse
techniques for flag complexes (e.g., Vietoris–Rips complexes). As a key technical
contribution, we describe how to induce a persistence map between two flag complexes
that have been independently simplified via edge collapses, even when a direct
simplicial map between them is no longer available.
acknowledgement: This project was partially funded by MCIN/AEI and the NextGenerationEU/PRTR,
under project TED2021-129438B-I00. The authors thank IMUS-Maria de Maeztu grant
CEX2024-001517-M - Apoyo a Unidades de Excelencia María de Maeztu for supporting
this research, funded by MICIU/AEI/ 10.13039/501100011033. The authors would also
like to thank Lars M Salbu for fruitful discussions regarding the operators from
Definition 4.1 and their relation with the order relations introduced in Definition
3.2.
article_number: '102598'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Rocio
full_name: Gonzalez-Diaz, Rocio
last_name: Gonzalez-Diaz
- first_name: Manuel
full_name: Soriano Trigueros, Manuel
id: 15ebd7cf-15bf-11ee-aebd-bb4bb5121ea8
last_name: Soriano Trigueros
orcid: 0000-0003-2449-1433
- first_name: Alvaro
full_name: Torras-Casas, Alvaro
last_name: Torras-Casas
citation:
ama: Gonzalez-Diaz R, Soriano Trigueros M, Torras-Casas A. Additive partial matchings
induced by persistence maps. Journal of Symbolic Computation. 2026;138.
doi:10.1016/j.jsc.2026.102598
apa: Gonzalez-Diaz, R., Soriano Trigueros, M., & Torras-Casas, A. (2026). Additive
partial matchings induced by persistence maps. Journal of Symbolic Computation.
Elsevier. https://doi.org/10.1016/j.jsc.2026.102598
chicago: Gonzalez-Diaz, Rocio, Manuel Soriano Trigueros, and Alvaro Torras-Casas.
“Additive Partial Matchings Induced by Persistence Maps.” Journal of Symbolic
Computation. Elsevier, 2026. https://doi.org/10.1016/j.jsc.2026.102598.
ieee: R. Gonzalez-Diaz, M. Soriano Trigueros, and A. Torras-Casas, “Additive partial
matchings induced by persistence maps,” Journal of Symbolic Computation,
vol. 138. Elsevier, 2026.
ista: Gonzalez-Diaz R, Soriano Trigueros M, Torras-Casas A. 2026. Additive partial
matchings induced by persistence maps. Journal of Symbolic Computation. 138, 102598.
mla: Gonzalez-Diaz, Rocio, et al. “Additive Partial Matchings Induced by Persistence
Maps.” Journal of Symbolic Computation, vol. 138, 102598, Elsevier, 2026,
doi:10.1016/j.jsc.2026.102598.
short: R. Gonzalez-Diaz, M. Soriano Trigueros, A. Torras-Casas, Journal of Symbolic
Computation 138 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: The code used for the computational experiments is available
in https://github.com/Cimagroup/IBloFunMatch
date_created: 2026-07-13T09:43:38Z
date_published: 2026-06-23T00:00:00Z
date_updated: 2026-07-13T12:00:07Z
day: '23'
ddc:
- '500'
department:
- _id: HeEd
doi: 10.1016/j.jsc.2026.102598
external_id:
arxiv:
- '2006.11100'
fulldoi: https://doi.org/10.1016/j.jsc.2026.102598
has_accepted_license: '1'
intvolume: ' 138'
keyword:
- Persistence module
- Persistence map
- Persistent homology
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1016/j.jsc.2026.102598
mathsc:
- 55N31
- 16G20
month: '06'
oa: 1
oa_version: Published Version
publication: Journal of Symbolic Computation
publication_identifier:
eissn:
- 1095-855X
issn:
- 0747-7171
publication_status: epub_ahead
publisher: Elsevier
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: no
title: Additive partial matchings induced by persistence maps
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 138
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '22289'
abstract:
- lang: eng
text: Single-stranded, helically folded aromatic oligoamides bearing anionic phosphonate
side chains have been shown to bind to some DNA-binding proteins better than DNA
itself. However, these DNA mimic foldamers have until now mainly consisted of
a single repeat motif, like a poly(dA:dT) DNA duplex, and contained limited sequence
information. Here, we introduce new monomers designed to display different chemical
functionalities in the major groove of the DNA mimics. Four new Fmoc-protected
amino acid monomers have been synthesized and incorporated into oligomers. Sixteen
foldamer sequences were prepared on solid phase. Their conformations in solution
and in the solid state and their conformational dynamics were investigated using
nuclear magnetic resonance, circular dichroism, molecular modeling, and X-ray
crystallography. The results show that three of the four new monomers behaved
as designed and that their introduction enhances the conformational dynamics of
the DNA mimic foldamers. In a fourth case, conformational behavior proved to be
more complex than expected. The modified sequences retained the ability to bind
to the bacterial histone-like protein HU. These results showcase design strategies
to manipulate large molecular biomimetics in which not only side chains but also
main chain components are varied. The new monomers pave the way to complex DNA
mimic foldamer sequences targeting proteins that recognize sequence-selective
DNA-binding proteins such as transcription factors or restriction enzymes.
acknowledgement: We acknowledge financial support from the European Research Council
(ERC) under the European Union's Horizon Europe Framework Programme (grant agreement
no. ERC-2021-ADG-320892) and from the China Scholarship Council (CSC, predoctoral
fellowship to J. W.). We thank L. Allmendinger for assistance with NMR measurements,
P. Mayer for his assistance in solving the crystal structures of 1 and 1d, L. Bodero
for assistance with automated solid-phase synthesis, M. Rogovoi for providing monomer
precursors, and M. Loos for the purification and analysis of compounds 15a–19a.
We thank M. Soler-Lopez (ID23-1, ESRF, Grenoble) and I. Bento (EMBL P13, Petra III,
DESY, Hamburg) for assistance during data collection at the synchrotron beamlines.
article_processing_charge: Yes
article_type: original
author:
- first_name: Jiaojiao
full_name: Wu, Jiaojiao
last_name: Wu
- first_name: Valentina
full_name: Corvaglia, Valentina
last_name: Corvaglia
- first_name: Tulika
full_name: Chakrabortty, Tulika
last_name: Chakrabortty
- first_name: Pradeep K
full_name: Mandal, Pradeep K
id: 6a3def15-d4b4-11ef-9fa9-a24c1f545ec3
last_name: Mandal
orcid: 0000-0001-5996-956X
- first_name: Ivan
full_name: Huc, Ivan
last_name: Huc
citation:
ama: Wu J, Corvaglia V, Chakrabortty T, Mandal PK, Huc I. Tailoring the major groove
of DNA mimic foldamers. Chemical Science. doi:10.1039/d6sc00798h
apa: Wu, J., Corvaglia, V., Chakrabortty, T., Mandal, P. K., & Huc, I. (n.d.).
Tailoring the major groove of DNA mimic foldamers. Chemical Science. Royal
Society of Chemistry. https://doi.org/10.1039/d6sc00798h
chicago: Wu, Jiaojiao, Valentina Corvaglia, Tulika Chakrabortty, Pradeep K Mandal,
and Ivan Huc. “Tailoring the Major Groove of DNA Mimic Foldamers.” Chemical
Science. Royal Society of Chemistry, n.d. https://doi.org/10.1039/d6sc00798h.
ieee: J. Wu, V. Corvaglia, T. Chakrabortty, P. K. Mandal, and I. Huc, “Tailoring
the major groove of DNA mimic foldamers,” Chemical Science. Royal Society
of Chemistry.
ista: Wu J, Corvaglia V, Chakrabortty T, Mandal PK, Huc I. Tailoring the major groove
of DNA mimic foldamers. Chemical Science.
mla: Wu, Jiaojiao, et al. “Tailoring the Major Groove of DNA Mimic Foldamers.” Chemical
Science, Royal Society of Chemistry, doi:10.1039/d6sc00798h.
short: J. Wu, V. Corvaglia, T. Chakrabortty, P.K. Mandal, I. Huc, Chemical Science
(n.d.).
das_tickbox: '1'
dataavailabilitystatement: "CCDC 2514117, 2514118, 2286782 and 2478322 (compound 1,
compound 1d, oligomer 5, and oligomer 6, respectively) contain the supplementary
crystallographic data for this paper.54a–d \r\n\r\nThe supporting data have been
provided as part of the supplementary information (SI). Supplementary information:
SI figures, detailed experimental protocols, crystallographic studies, and characterisation
of new compounds. See DOI: https://doi.org/10.1039/d6sc00798h."
date_created: 2026-07-13T09:41:36Z
date_published: 2026-06-09T00:00:00Z
date_updated: 2026-07-13T11:24:29Z
day: '09'
ddc:
- '540'
department:
- _id: LifeSc
doi: 10.1039/d6sc00798h
fulldoi: https://doi.org/10.1039/d6sc00798h
has_accepted_license: '1'
language:
- iso: eng
month: '06'
oa_version: Published Version
publication: Chemical Science
publication_identifier:
eissn:
- 2041-6539
issn:
- 2041-6520
publication_status: inpress
publisher: Royal Society of Chemistry
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Tailoring the major groove of DNA mimic foldamers
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '22290'
abstract:
- lang: eng
text: We introduce a multi-band BCS free energy functional and prove that for a
multi-band superconductor the effect of inter-band coupling can only increase
the critical temperature, irrespective of its attractive or repulsive nature and
its strength. Further, for weak coupling and weaker inter-band coupling, we prove
that the dependence of the increase in critical temperature on the inter-band
coupling is (1) linear, if there are two or more equally strongly superconducting
bands, or (2) quadratic, if there is only one dominating band.
acknowledgement: 'We would like to thank J. Lenells and R. Seiringer for their interest
and helpful discussions, E. Babaev and Y. Yerin for useful comments about the literature,
and the anonymous referee for their comments. J.H. gratefully acknowledges partial
financial support by the ERC Advanced Grant “RMTBeyond” No. 101020331 and the ERC
Consollidator Grant “ProbQuant” (jointly with the Swiss State Secretariat for Education,
Research and Innovation). E.L. gratefully acknowledges support from the Swedish
Research Council, Grant No. 2023-04726. A.B.L. gratefully acknowledges partial financial
support by the Austrian Science Fund (FWF) through grant DOI: 10.55776/I6427 (as
part of the SFB/TRR 352) and by the French State support managed by ANR under the
France 2030 program through the MaQuI CNRS Risky and High-Impact Research programme
(RI)^2 (grant agreement ANR-24-RRII-0001). Open access funding provided by Royal
Institute of Technology.'
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Sven Joscha
full_name: Henheik, Sven Joscha
id: 31d731d7-d235-11ea-ad11-b50331c8d7fb
last_name: Henheik
orcid: 0000-0003-1106-327X
- first_name: Edwin
full_name: Langmann, Edwin
last_name: Langmann
- first_name: Asbjørn Bækgaard
full_name: Lauritsen, Asbjørn Bækgaard
id: e1a2682f-dc8d-11ea-abe3-81da9ac728f1
last_name: Lauritsen
orcid: 0000-0003-4476-2288
citation:
ama: Henheik SJ, Langmann E, Lauritsen AB. Multi-band superconductors have enhanced
critical temperatures. Annales Henri Poincaré. 2026. doi:10.1007/s00023-026-01706-y
apa: Henheik, S. J., Langmann, E., & Lauritsen, A. B. (2026). Multi-band superconductors
have enhanced critical temperatures. Annales Henri Poincaré. Springer Nature.
https://doi.org/10.1007/s00023-026-01706-y
chicago: Henheik, Sven Joscha, Edwin Langmann, and Asbjørn Bækgaard Lauritsen. “Multi-Band
Superconductors Have Enhanced Critical Temperatures.” Annales Henri Poincaré.
Springer Nature, 2026. https://doi.org/10.1007/s00023-026-01706-y.
ieee: S. J. Henheik, E. Langmann, and A. B. Lauritsen, “Multi-band superconductors
have enhanced critical temperatures,” Annales Henri Poincaré. Springer
Nature, 2026.
ista: Henheik SJ, Langmann E, Lauritsen AB. 2026. Multi-band superconductors have
enhanced critical temperatures. Annales Henri Poincaré.
mla: Henheik, Sven Joscha, et al. “Multi-Band Superconductors Have Enhanced Critical
Temperatures.” Annales Henri Poincaré, Springer Nature, 2026, doi:10.1007/s00023-026-01706-y.
short: S.J. Henheik, E. Langmann, A.B. Lauritsen, Annales Henri Poincaré (2026).
das_tickbox: '1'
dataavailabilitystatement: Data sharing is not applicable to this article as no new
data were created or analyzed in this study.
date_created: 2026-07-13T09:42:22Z
date_published: 2026-06-29T00:00:00Z
date_updated: 2026-07-13T11:34:08Z
day: '29'
ddc:
- '500'
department:
- _id: LaEr
- _id: RoSe
doi: 10.1007/s00023-026-01706-y
ec_funded: 1
external_id:
arxiv:
- '2409.17297'
fulldoi: https://doi.org/10.1007/s00023-026-01706-y
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1007/s00023-026-01706-y
month: '06'
oa: 1
oa_version: Published Version
project:
- _id: 62796744-2b32-11ec-9570-940b20777f1d
call_identifier: H2020
grant_number: '101020331'
name: Random matrices beyond Wigner-Dyson-Mehta
- _id: bda63fe5-d553-11ed-ba76-a16e3d2f256b
grant_number: I06427
name: Mathematical Challenges in BCS Theory of Superconductivity
publication: Annales Henri Poincaré
publication_identifier:
eissn:
- 1424-0661
issn:
- 1424-0637
publication_status: epub_ahead
publisher: Springer Nature
quality_controlled: '1'
related_material:
record:
- id: '19550'
relation: earlier_version
status: public
researchdata_availability: not applicable
scopus_import: '1'
status: public
supplementarymaterial: not applicable
title: Multi-band superconductors have enhanced critical temperatures
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
OA_place: repository
OA_type: green
_id: '22292'
abstract:
- lang: eng
text: We show that a suitable choice of boundary conditions for the Laplacian allows
for the appearance of an arbitrary number of condensates, described by arbitrary
harmonic functions, in the thermodynamic limit of an ideal Bose gas.
acknowledgement: We are grateful to Rupert Frank and Jakob Yngvason for helpful discussions
and suggestions.
article_number: '061901'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Michiel
full_name: De Wilde, Michiel
id: bebf1407-6635-11f0-9fef-9b7e2dd151d0
last_name: De Wilde
- first_name: Robert
full_name: Seiringer, Robert
id: 4AFD0470-F248-11E8-B48F-1D18A9856A87
last_name: Seiringer
orcid: 0000-0002-6781-0521
citation:
ama: De Wilde M, Seiringer R. Arbitrary harmonic functions as Bose–Einstein condensates.
Journal of Mathematical Physics. 2026;67(6). doi:10.1063/5.0325354
apa: De Wilde, M., & Seiringer, R. (2026). Arbitrary harmonic functions as Bose–Einstein
condensates. Journal of Mathematical Physics. AIP Publishing. https://doi.org/10.1063/5.0325354
chicago: De Wilde, Michiel, and Robert Seiringer. “Arbitrary Harmonic Functions
as Bose–Einstein Condensates.” Journal of Mathematical Physics. AIP Publishing,
2026. https://doi.org/10.1063/5.0325354.
ieee: M. De Wilde and R. Seiringer, “Arbitrary harmonic functions as Bose–Einstein
condensates,” Journal of Mathematical Physics, vol. 67, no. 6. AIP Publishing,
2026.
ista: De Wilde M, Seiringer R. 2026. Arbitrary harmonic functions as Bose–Einstein
condensates. Journal of Mathematical Physics. 67(6), 061901.
mla: De Wilde, Michiel, and Robert Seiringer. “Arbitrary Harmonic Functions as Bose–Einstein
Condensates.” Journal of Mathematical Physics, vol. 67, no. 6, 061901,
AIP Publishing, 2026, doi:10.1063/5.0325354.
short: M. De Wilde, R. Seiringer, Journal of Mathematical Physics 67 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: Data sharing is not applicable to this article as no new
data were created or analyzed in this study.
date_created: 2026-07-13T09:45:09Z
date_published: 2026-06-01T00:00:00Z
date_updated: 2026-07-13T12:20:59Z
day: '01'
department:
- _id: RoSe
- _id: GradSch
doi: 10.1063/5.0325354
external_id:
arxiv:
- '2601.22883'
fulldoi: https://doi.org/10.1063/5.0325354
intvolume: ' 67'
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.48550/arXiv.2601.22883
month: '06'
oa: 1
oa_version: Preprint
publication: Journal of Mathematical Physics
publication_identifier:
eissn:
- 1089-7658
issn:
- 0022-2488
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
researchdata_availability: not applicable
scopus_import: '1'
status: public
supplementarymaterial: not applicable
title: Arbitrary harmonic functions as Bose–Einstein condensates
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 67
year: '2026'
...
---
OA_type: closed access
_id: '22293'
abstract:
- lang: eng
text: In order to cope with arid terrestrial environments, angiosperms have evolved
a unique fertilization way—siphonogamy. The success of siphonogamy requires several
prerequisites, including the normal development of the female gametophyte and
male gametophyte (pollen). Appropriate pollination methods ensure the successful
encounter between pollen and the stigma. After pollen lands on the stigma, pollen/pollen
tube interacts with different tissues and cells of the pistil, completing a series
of male-female communications. The smooth progress of these interactions ensures
that the pollen tube can enter the female gametophyte, burst, and release sperm
cells to complete the double fertilization. In this chapter, we provide an overview
of pollination and the interactions between male and female, comprehensively summarizing
the factors involved in these processes.
article_processing_charge: No
author:
- first_name: Sheng
full_name: Zhong, Sheng
last_name: Zhong
- first_name: Zijun
full_name: Lan, Zijun
last_name: Lan
- first_name: Zengxiang
full_name: Ge, Zengxiang
id: f43371a3-09ff-11eb-8013-bd0c6a2f6de8
last_name: Ge
orcid: 0000-0001-9381-3577
- first_name: Li-Jia
full_name: Qu, Li-Jia
last_name: Qu
citation:
ama: 'Zhong S, Lan Z, Ge Z, Qu L-J. Pollination and Fertilization. In: Chang F,
Wang Y, Ma H, eds. Regulation of Plant Development. Singapore: Springer
Nature; 2026:537-615. doi:10.1007/978-981-95-7033-1_14'
apa: 'Zhong, S., Lan, Z., Ge, Z., & Qu, L.-J. (2026). Pollination and Fertilization.
In F. Chang, Y. Wang, & H. Ma (Eds.), Regulation of Plant Development
(pp. 537–615). Singapore: Springer Nature. https://doi.org/10.1007/978-981-95-7033-1_14'
chicago: 'Zhong, Sheng, Zijun Lan, Zengxiang Ge, and Li-Jia Qu. “Pollination and
Fertilization.” In Regulation of Plant Development, edited by Fang Chang,
Yingxiang Wang, and Hong Ma, 537–615. Singapore: Springer Nature, 2026. https://doi.org/10.1007/978-981-95-7033-1_14.'
ieee: 'S. Zhong, Z. Lan, Z. Ge, and L.-J. Qu, “Pollination and Fertilization,” in
Regulation of Plant Development, F. Chang, Y. Wang, and H. Ma, Eds. Singapore:
Springer Nature, 2026, pp. 537–615.'
ista: 'Zhong S, Lan Z, Ge Z, Qu L-J. 2026.Pollination and Fertilization. In: Regulation
of Plant Development. , 537–615.'
mla: Zhong, Sheng, et al. “Pollination and Fertilization.” Regulation of Plant
Development, edited by Fang Chang et al., Springer Nature, 2026, pp. 537–615,
doi:10.1007/978-981-95-7033-1_14.
short: S. Zhong, Z. Lan, Z. Ge, L.-J. Qu, in:, F. Chang, Y. Wang, H. Ma (Eds.),
Regulation of Plant Development, Springer Nature, Singapore, 2026, pp. 537–615.
das_tickbox: '1'
date_created: 2026-07-13T09:46:18Z
date_published: 2026-04-24T00:00:00Z
date_updated: 2026-07-13T12:25:19Z
day: '24'
department:
- _id: JiFr
doi: 10.1007/978-981-95-7033-1_14
editor:
- first_name: 'Fang '
full_name: 'Chang, Fang '
last_name: Chang
- first_name: Yingxiang
full_name: Wang, Yingxiang
last_name: Wang
- first_name: Hong
full_name: Ma, Hong
last_name: Ma
fulldoi: https://doi.org/10.1007/978-981-95-7033-1_14
language:
- iso: eng
month: '04'
oa_version: None
page: 537-615
place: Singapore
publication: Regulation of Plant Development
publication_identifier:
eisbn:
- '9789819570331'
isbn:
- '9789819570324'
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Pollination and Fertilization
type: book_chapter
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21378'
abstract:
- lang: eng
text: From insects to mammals, essential brain functions, such as forming long-term
memories (LTMs), increase metabolic activity in stimulated neurons to meet the
energetic demand associated with brain activation. However, while impairing neuronal
metabolism limits brain performance, whether expanding the metabolic capacity
of neurons boosts brain function remains poorly understood. Here, we show that
LTM formation of flies and mice can be enhanced by increasing mitochondrial metabolism
in central memory circuits. By knocking down the mitochondrial Ca2+ exporter Letm1,
we favour Ca2+ retention in the mitochondrial matrix of neurons due to reduction
of mitochondrial H+/Ca2+ exchange. The resulting increase in mitochondrial Ca2+
over-activates mitochondrial metabolism in neurons of central memory circuits,
leading to improved LTM storage in training paradigms in which wild-type counterparts
of both species fail to remember. Our findings unveil an evolutionarily conserved
mechanism that controls mitochondrial metabolism in neurons and indicate its involvement
in shaping higher brain functions, such as LTM.
acknowledgement: We thank all members of the laboratory of J.d.J.-S. for insightful
discussions and comments. We thank S. Perez for technical assistance. This work
was made possible by the Paris Brain Institute Diane Barriere Chair in Synaptic
Bioenergetics awarded to J.d.J.-S., who is also supported by an ERC Starting Grant
(SynaptoEnergy, European Research Council; ERC-StG-852873), 2019 ATIP-Avenir Grant
(CNRS, Inserm), a Big Brain Theory Grant (ICM Foundation) and a Kavli Exploratory
Award (Kavli Foundation). This work was also supported by an ERC Advanced Grant
(EnergyMeMo; ERC-AdG-741550) to T.P. and grants from the Agence Nationale de la
Recherche to P.Y.P. (ANR-20-CE92-0047-01), T.P. (ANR-23-CE16-0029-01), A.P. and
J.d.J.-S. (ANR-22-CE16-0020) and J.d.J.-S. (ANR-24-CE16-0221). T.P., P.Y.P. and
J.d.J.-S. are permanent CNRS researchers. A.P. is a permanent ESPCI associate professor.
T.C. was funded by the French Ministry of Research and the Fondation pour la Recherche
Médicale. V.R. was funded by the Max Planck Society, the Chan Zuckerberg Initiative
DAF, an advised fund of the Silicon Valley Community Foundation grant number 2024-349543
and the NIH Director’s New Innovator Award (DP2 MH140148). A.B.-G. and C.R.-D. received
funding from an ERC Starting Grant (HighMemory; ERC-StG-948217), the Ministry of
Economy and Competitiveness (PID2021-122795OB-I00) and the Departament d’Economia
i Coneixement de la Generalitat de Catalunya (SGR 00022). T.P.V. was funded by the
Wellcome Trust and a Royal Society Sir Henry Dale Research Fellowship (WT100000)
and a Wellcome Trust Senior Research Fellowship (214316/Z/18/Z). K.G. was supported
by the DIM C-BRAINS, funded by the Conseil Régional d’Ile-de-France. The contributions
of H.F. and E.R.S. were supported by the Howard Hughes Medical Institute. The PHENO-ICMice
animal Core at ICM is supported by two ‘Investissements d’avenir’ (ANR-10- IAIHU-06
and ANR-11-INBS-0011-NeurATRIS) and the Fondation pour la Recherche Médicale.
article_processing_charge: Yes (in subscription journal)
article_type: original
author:
- first_name: Anjali
full_name: Amrapali Vishwanath, Anjali
last_name: Amrapali Vishwanath
- first_name: Typhaine
full_name: Comyn, Typhaine
last_name: Comyn
- first_name: Rodrigo G.
full_name: Mira, Rodrigo G.
last_name: Mira
- first_name: Claire
full_name: Brossier, Claire
last_name: Brossier
- first_name: Carlos
full_name: Pascual-Caro, Carlos
last_name: Pascual-Caro
- first_name: Maya
full_name: Faour, Maya
last_name: Faour
- first_name: Kahina
full_name: Boumendil, Kahina
last_name: Boumendil
- first_name: Chaitanya
full_name: Chintaluri, Chaitanya
id: BA06AFEE-A4BA-11EA-AE5C-14673DDC885E
last_name: Chintaluri
orcid: 0000-0003-4252-1608
- first_name: Carla
full_name: Ramon-Duaso, Carla
last_name: Ramon-Duaso
- first_name: Ruolin
full_name: Fan, Ruolin
last_name: Fan
- first_name: Kishalay
full_name: Ghosh, Kishalay
last_name: Ghosh
- first_name: Helen
full_name: Farrants, Helen
last_name: Farrants
- first_name: Jean-Paul
full_name: Berwick, Jean-Paul
last_name: Berwick
- first_name: Riya
full_name: Sivakumar, Riya
last_name: Sivakumar
- first_name: Mario
full_name: Lopez-Manzaneda, Mario
last_name: Lopez-Manzaneda
- first_name: Eric R.
full_name: Schreiter, Eric R.
last_name: Schreiter
- first_name: Thomas
full_name: Preat, Thomas
last_name: Preat
- first_name: Tim P
full_name: Vogels, Tim P
id: CB6FF8D2-008F-11EA-8E08-2637E6697425
last_name: Vogels
orcid: 0000-0003-3295-6181
- first_name: Vidhya
full_name: Rangaraju, Vidhya
last_name: Rangaraju
- first_name: Arnau
full_name: Busquets-Garcia, Arnau
last_name: Busquets-Garcia
- first_name: Pierre-Yves
full_name: Plaçais, Pierre-Yves
last_name: Plaçais
- first_name: Alice
full_name: Pavlowsky, Alice
last_name: Pavlowsky
- first_name: Jaime
full_name: de Juan-Sanz, Jaime
last_name: de Juan-Sanz
citation:
ama: Amrapali Vishwanath A, Comyn T, Mira RG, et al. Mitochondrial Ca2+ efflux controls
neuronal metabolism and long-term memory across species. Nature Metabolism.
2026;8(2):467-488. doi:10.1038/s42255-026-01451-w
apa: Amrapali Vishwanath, A., Comyn, T., Mira, R. G., Brossier, C., Pascual-Caro,
C., Faour, M., … de Juan-Sanz, J. (2026). Mitochondrial Ca2+ efflux controls neuronal
metabolism and long-term memory across species. Nature Metabolism. Springer
Nature. https://doi.org/10.1038/s42255-026-01451-w
chicago: Amrapali Vishwanath, Anjali, Typhaine Comyn, Rodrigo G. Mira, Claire Brossier,
Carlos Pascual-Caro, Maya Faour, Kahina Boumendil, et al. “Mitochondrial Ca2+
Efflux Controls Neuronal Metabolism and Long-Term Memory across Species.” Nature
Metabolism. Springer Nature, 2026. https://doi.org/10.1038/s42255-026-01451-w.
ieee: A. Amrapali Vishwanath et al., “Mitochondrial Ca2+ efflux controls
neuronal metabolism and long-term memory across species,” Nature Metabolism,
vol. 8, no. 2. Springer Nature, pp. 467–488, 2026.
ista: Amrapali Vishwanath A, Comyn T, Mira RG, Brossier C, Pascual-Caro C, Faour
M, Boumendil K, Chintaluri C, Ramon-Duaso C, Fan R, Ghosh K, Farrants H, Berwick
J-P, Sivakumar R, Lopez-Manzaneda M, Schreiter ER, Preat T, Vogels TP, Rangaraju
V, Busquets-Garcia A, Plaçais P-Y, Pavlowsky A, de Juan-Sanz J. 2026. Mitochondrial
Ca2+ efflux controls neuronal metabolism and long-term memory across species.
Nature Metabolism. 8(2), 467–488.
mla: Amrapali Vishwanath, Anjali, et al. “Mitochondrial Ca2+ Efflux Controls Neuronal
Metabolism and Long-Term Memory across Species.” Nature Metabolism, vol.
8, no. 2, Springer Nature, 2026, pp. 467–88, doi:10.1038/s42255-026-01451-w.
short: A. Amrapali Vishwanath, T. Comyn, R.G. Mira, C. Brossier, C. Pascual-Caro,
M. Faour, K. Boumendil, C. Chintaluri, C. Ramon-Duaso, R. Fan, K. Ghosh, H. Farrants,
J.-P. Berwick, R. Sivakumar, M. Lopez-Manzaneda, E.R. Schreiter, T. Preat, T.P.
Vogels, V. Rangaraju, A. Busquets-Garcia, P.-Y. Plaçais, A. Pavlowsky, J. de Juan-Sanz,
Nature Metabolism 8 (2026) 467–488.
das_tickbox: '1'
date_created: 2026-03-02T10:04:49Z
date_published: 2026-02-11T00:00:00Z
date_updated: 2026-07-13T12:30:14Z
day: '11'
ddc:
- '570'
department:
- _id: TiVo
doi: 10.1038/s42255-026-01451-w
external_id:
pmid:
- '41673453'
file:
- access_level: open_access
checksum: 365932a599d05bc9ce8a57204e7a1465
content_type: application/pdf
creator: dernst
date_created: 2026-03-02T15:21:27Z
date_updated: 2026-03-02T15:21:27Z
file_id: '21392'
file_name: 2026_NatureMetab_AmrapaliVishwanath.pdf
file_size: 5326608
relation: main_file
success: 1
file_date_updated: 2026-03-02T15:21:27Z
fulldoi: https://doi.org/10.1038/s42255-026-01451-w
has_accepted_license: '1'
intvolume: ' 8'
issue: '2'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
page: 467-488
pmid: 1
project:
- _id: c084a126-5a5b-11eb-8a69-d75314a70a87
grant_number: 214316/Z/18/Z
name: What’s in a memory? Spatiotemporal dynamics in strongly coupled recurrent
neuronal networks.
publication: Nature Metabolism
publication_identifier:
eissn:
- 2522-5812
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Mitochondrial Ca2+ efflux controls neuronal metabolism and long-term memory
across species
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 8
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '22296'
abstract:
- lang: eng
text: 'The detection of strong Balmer breaks and absorption features in Little Red
Dots (LRDs) suggests they host active galactic nuclei embedded within dense gas
envelopes, potentially powered by super-Eddington accretion. We present GLIMPSE-17775,
a luminous (Lbol ∼ 1045 erg s−1) LRD at z = 3.501 behind Abell S1063 (μ ∼ 2),
observed with deep JWST/NIRCam and a ∼20 hr (80 hr delensed) NIRSpec G395M spectrum.
The data reveal over 40 emission and absorption features, including a rich forest
of low-ionization Fe ii lines and numerous broad hydrogen recombination transitions.
We use this depth to test the dense-gas interpretation through five independent
diagnostics. Nearly all permitted lines show exponential wings with consistent
FWHM, a signature of Thomson scattering requiring ne ≳ 108 cm−3. Adopting this
width yields MBH ∼ 106.7M⊙, a factor of 10 lower than Gaussian fits, and λEdd
∼ 1.8. Additional diagnostics support the same picture: a pronounced Balmer break
(fν,4050/fν,3670 = 2.0 ± 0.1), enhanced He i λ7065 and λ10830 with P-Cygni absorption,
Bowen-fluorescent O i λ8446–λ11290 emission requiring Lyβ pumping, and 16 Fe ii
lines matching fluorescence models. These features indicate a dense (n ∼ 108 cm−3),
partially ionized cocoon where scattering and fluorescence dominate line formation,
providing strong evidence that at least some LRDs are powered by super-Eddington
black hole growth in the early Universe.'
acknowledgement: "IOP Science home\r\nThe Astrophysical Journal\r\nThe American Astronomical
Society, find out more.\r\n\r\nThe following article isOpen access\r\nThe Deepest
GLIMPSE of a Dense Gas Cocoon Enshrouding a Little Red Dot\r\nVasily Kokorev, John
Chisholm, Rohan P. Naidu, Seiji Fujimoto, Hakim Atek, Gabriel Brammer, Steven L.
Finkelstein, Hollis B. Akins, Danielle A. Berg, Lukas J. FurtakShow full author
list\r\n\r\nPublished 2026 June 10 • © 2026. The Author(s). Published by the American
Astronomical Society.\r\nThe Astrophysical Journal, Volume 1004, Number 2\r\nCitation
Vasily Kokorev et al 2026 ApJ 1004 153\r\nDOI 10.3847/1538-4357/ae4ed7\r\n\r\nPDFOpens
in a new tab.ePub\r\nAuthors\r\nFigures\r\nTables\r\nReferences\r\nArticle data\r\nPDFOpens
in a new tab.ePub\r\nArticle metrics\r\n5138 Total downloads\r\n\r\n22 total citations
on Dimensions.\r\nShare this article\r\nArticle information\r\nAbstract\r\nThe detection
of strong Balmer breaks and absorption features in Little Red Dots (LRDs) suggests
they host active galactic nuclei embedded within dense gas envelopes, potentially
powered by super-Eddington accretion. We present GLIMPSE-17775, a luminous (Lbol
∼ 1045 erg s−1) LRD at z = 3.501 behind Abell S1063 (μ ∼ 2), observed with deep
JWST/NIRCam and a ∼20 hr (80 hr delensed) NIRSpec G395M spectrum. The data reveal
over 40 emission and absorption features, including a rich forest of low-ionization
Fe ii lines and numerous broad hydrogen recombination transitions. We use this depth
to test the dense-gas interpretation through five independent diagnostics. Nearly
all permitted lines show exponential wings with consistent FWHM, a signature of
Thomson scattering requiring ne ≳ 108 cm−3. Adopting this width yields MBH ∼ 106.7M⊙,
a factor of 10 lower than Gaussian fits, and λEdd ∼ 1.8. Additional diagnostics
support the same picture: a pronounced Balmer break (fν,4050/fν,3670 = 2.0 ± 0.1),
enhanced He i λ7065 and λ10830 with P-Cygni absorption, Bowen-fluorescent O i λ8446–λ11290
emission requiring Lyβ pumping, and 16 Fe ii lines matching fluorescence models.
These features indicate a dense (n ∼ 108 cm−3), partially ionized cocoon where scattering
and fluorescence dominate line formation, providing strong evidence that at least
some LRDs are powered by super-Eddington black hole growth in the early Universe.\r\n\r\nExport
citation and abstract\r\nBibTeXRIS\r\n\r\nPrevious article in issue\r\nNext article
in issue\r\nRelated links\r\n\r\nOriginal content from this work may be used under
the terms of the Creative Commons Attribution 4.0 licence. Any further distribution
of this work must maintain attribution to the author(s) and the title of the work,
journal citation and DOI.\r\n\r\n1. Introduction\r\nOne of the most enticing puzzles
brought about by the launch of the James Webb Space Telescope (JWST) has been the
discovery of red, compact objects called “Little Red Dots” (LRDs; J. Matthee et
al. 2024). Previously invisible to the Hubble Space Telescope (HST) due to their
extreme faintness in the optical and lack of near-infrared (NIR) coverage, LRDs
have emerged in abundance (V. Kokorev et al. 2024a; H. B. Akins et al. 2025a; D.
D. Kocevski et al. 2025; G. Barro et al. 2026) thanks to the unprecedented NIR sensitivity
of JWST.\r\n\r\nTheir unusual properties—such as compact morphologies in rest-optical
and distinctive “V-shaped” spectral energy distributions (SEDs)—make LRDs easy to
identify in JWST fields; however, this is where the simplicity ends. Explaining
LRDs as either evolved or dusty compact galaxies proves difficult: The former scenario
requires massive stellar populations that strain Lambda cold dark matter (ΛCDM)
predictions (M. Boylan-Kolchin 2023; I. Labbé et al. 2023), while the latter implies
significant dust emission, yet none is observed (C. M. Casey et al. 2024; G. C.
K. Leung et al. 2025; H. B. Akins et al. 2025a; I. Labbé et al. 2025).\r\n\r\nOver
time, the accumulating detections of broad Balmer-series emission lines (D. D. Kocevski
et al. 2023, 2025; J. Matthee et al. 2024, just to name a few), often accompanied
by signatures of extreme ionization (e.g., V. Kokorev et al. 2023), have begun to
clarify the physical origin of LRDs, pointing increasingly toward active galactic
nuclei (AGN) as the underlying power source. In parallel, the much needed advent
of NIRSpec Micro Shutter Assembly (MSA) programs based on red targets selected from
JWST imaging (e.g., A. de Graaff et al. 2025b) has provided critical confirmation:
Nearly all point sources exhibiting “V-shaped” SEDs reveal broad emission lines
upon spectroscopic follow-up (R. E. Hviding et al. 2025), solidifying their AGN
interpretation.\r\n\r\nThe nature of the spectral inflection point in LRDs, typically
located near ∼3600 Å, has also undergone significant revision. Initially interpreted
as a stellar Balmer break (I. Labbé et al. 2023), this feature implied implausibly
high stellar masses (M*) far too early in cosmic history (M. Boylan-Kolchin 2023;
N. Sabti et al. 2024). A second hypothesis invoked differential dust attenuation
and host-galaxy contamination in the rest-UV to explain the sharp discontinuity
(M. Volonteri et al. 2025). However, this explanation was soon ruled out by D. J.
Setton et al. (2025) and Y. Ma et al. (2025), who demonstrated that the break generally
lies around the Balmer limit, albeit with a fundamentally different origin than
initially proposed.\r\n\r\nMore recently, a series of theoretical and observational
works have converged on a new picture in which LRDs may host accreting black holes
enshrouded in exceptionally dense, partially ionized gas cocoons, often referred
to as “black hole stars” (hereafter BH*; A. de Graaff et al. 2025b; K. Inayoshi
& R. Maiolino 2025; R. P. Naidu et al. 2025; A. J. Taylor et al. 2025). Here, BH*
is used in an empirical sense to denote cocooned black holes whose emergent spectra
exhibit a combination of black-hole-like and star-like features, such as broad permitted
lines, steep Balmer-limit breaks, and Balmer absorption, as observed in the archetypal
BH* sources (A. de Graaff et al. 2025b; R. P. Naidu et al. 2025). This usage does
not assume a specific geometry or formation channel: The underlying physical picture
involves an AGN power-law ionizing spectrum processed through very dense gas, and
similar phenomenology can arise in a range of dense-gas configurations (e.g., K.
Inayoshi & R. Maiolino 2025; D. Kido et al. 2025; H. Liu et al. 2025; A. Sneppen
et al. 2026). In such environments, suppressed X-ray and radio emission (e.g., K.
Inayoshi & R. Maiolino 2025; R. P. Naidu et al. 2025) arise naturally from the high
optical depth, while the UV emission and forbidden optical lines (e.g., [O iii]
λλ4959, 5007) may originate in the more extended host (e.g., A. de Graaff et al.
2025d).\r\n\r\nThe dense-gas interpretation also offers a natural explanation for
the P-Cygni-like Balmer and helium profiles frequently seen in high-signal-to-noise-ratio
(S/N) spectra (J. Matthee et al. 2024), the non-Gaussian, exponentially winged line
shapes predicted by radiative-transfer models of scattering in ionized gas (S.-J.
Chang et al. 2026; V. Rusakov et al. 2026), and Lyα-like resonantly scattered shapes
(R. P. Naidu et al. 2025; S.-J. Chang et al. 2026). Intriguingly, if electron and
resonant scattering indeed dominate the broad-line widths, then the true virial
velocities (traced by intrinsically narrower Gaussian cores)—and hence black hole
masses—could be lower by an order of magnitude, alleviating the apparent tension
between LRD black hole masses and their compact host galaxies (V. Rusakov et al.
2026).\r\n\r\nSo far, however, the BH*/dense-gas interpretation of LRDs has relied
largely on the Balmer break, occasional absorption features (X. Lin et al. 2026),
and, to a limited extent, the shapes of broad emission lines (V. Rusakov et al.
2026). While these features are consistent with the presence of dense, partially
ionized gas, they stop short of providing direct spectroscopic confirmation of the
physical conditions expected by the BH* scenario. What has been missing is an unambiguous
demonstration—through emission-line physics—that LRDs indeed host dense, optically
thick cocoons surrounding rapidly accreting black holes. Such evidence would directly
tie the observed line formation, excitation, and radiative transfer to dense, stratified
envelopes of gas surrounding the central engine.\r\n\r\nIn this work, we present
precisely such a case: an exceptionally deep, ∼20 hr (equivalent to 80 hr without
lensing magnification) JWST/NIRSpec G395M spectrum of a luminous LRD at z = 3.50102.
The target, GLIMPSE-17775, lies in a highly magnified region of the massive galaxy
cluster Abell S1063 (hereafter AS1063) and benefits from the combined power of JWST/NIRCam
imaging from the GLIMPSE GO program (PID 3293; PIs: H. Atek & J. Chisholm) and recent
NIRSpec spectroscopy from the GLIMPSEDirector's Discretionary Time (DDT) (hereafter
GLIMPSE-D) program (PID 9223; PIs: S. Fujimoto & R. Naidu). This synergy of ultradeep
spectroscopy and strong gravitational lensing enables an unprecedented view of GLIMPSE-17775,
revealing rest-frame optical and NIR features at a level unseen before in any LRD.
We detect over 40 emission and absorption features, including 16 Fe ii transitions
that form a dense “iron forest.” The remarkable richness of this spectrum makes
GLIMPSE-17775 a uniquely powerful laboratory for dissecting the dense, radiation-dominated
environments that accompany early black hole growth.\r\n\r\nThis paper is organized
as follows. In Section 2, we present the GLIMPSE-D NIRSpec dataset alongside the
photometric datasets used in this study. In Section 3, we calculate the spectroscopic
redshift, describe the identification of prominent emission/absorption features,
and describe bespoke fitting of various line complexes. Section 4 describes the
measurement of the source morphology, dust attenuation, and black hole masses. In
Section 5, we comment on the various properties of the emission features in the
our target. Finally, we discuss our findings in Section 6.\r\n\r\nThroughout this
work, we assume a flat ΛCDM cosmology with Ωm,0 = 0.3, ΩΛ,0 = 0.7, and H0 = 70 km
s−1 Mpc−1, and a G. Chabrier (2003) initial mass function between 0.1 and 100M⊙.
All magnitudes are expressed in the AB system (J. B. Oke 1974).\r\n\r\n2. Observations
and Data\r\nThe target, GLIMPSE-17775, was originally identified as a bright LRD
candidate in JWST/NIRCam imaging captured by the GLIMPSE (PID: 3293; PIs: H. Atek
& J. Chisholm) survey (H. Atek et al. 2025) of the lensed AS1063 Hubble Frontier
Field (HFF; J. M. Lotz et al. 2017). The highly magnified area of AS1063 has already
successfully yielded z > 16 galaxy candidates (V. Kokorev et al. 2025), potential
Population III (Pop III) hosts (S. Fujimoto et al. 2025a), numerous faint and high-redshift
galaxies (I. Chemerynska et al. 2026), new constraints on reionization (D. Korber
et al. 2025), identification of intermediate-mass black holes (Q. Fei et al. 2025),
and a wide variety of enigmatic LRDs, some moderately lensed. The LRD selection
was based on the standard compactness plus “V-shape” criteria already laid out in
J. E. Greene et al. (2024), V. Kokorev et al. (2024a), H. B. Akins et al. (2025a),
and I. Labbé et al. (2025) using photometric redshifts derived with eazy (G. B.
Brammer et al. 2008), a technique that has proven successful at consistently identifying
many exciting sources (see, e.g., H. B. Akins et al. 2025b; A. de Graaff et al.
2025b; V. Kokorev et al. 2023; R. P. Naidu et al. 2025; A. J. Taylor et al. 2025).
Located at zphot = 4.2 ± 0.1, GLIMPSE-17775 stood out in particular due to its extreme
rest-optical brightness with mf444w ∼ 23.6 mag and a modest lensing magnification
μ ∼ 2. While very little could be done with photometry alone, this marked GLIMPSE-17775
as a promising target for any future spectroscopic follow-up.\r\n\r\n2.1. Photometry\r\nWe
use photometry both to select targets for the GLIMPSE-D NIRSpec observations and,
during spectroscopic modeling, to constrain the overall shape of the SED and correct
for NIRSpec slit losses. In addition to JWST/NIRCam data, we incorporate deep HST
Advanced Camera for Surveys and Wide Field Camera 3 imaging from the HFF (J. M.
Lotz et al. 2017) and BUFFALO (C. L. Steinhardt et al. 2020) programs. Our reprocessed
HST mosaics are based on Gaia-aligned images from the CHArGE archive (V. Kokorev
et al. 2022), hosted on the Dawn JWST Archive (F. Valentino et al. 2023). More descriptions
of the image reduction and source extraction procedure can be found in R. Endsley
et al. (2025), as well as in the GLIMPSE overview paper (H. Atek et al. 2025); we
briefly summarize the latter procedure below.\r\n\r\nPhotometry is performed on
point-spread function (PSF)-homogenized HST and JWST images, convolved to the resolution
of the F480M filter. Source detection is carried out using SExtractor (E. Bertin
& S. Arnouts 1996) through two parallel steps. We construct two inverse-variance-weighted
detection images: one from the short-wavelength (SW; F090W, F115W, F150W, F200W)
bands to preserve spatial resolution, and one from the long-wavelength (LW; F277W,
F356W, F444W) bands to ensure sensitivity to red or dusty sources (e.g., LRDs).
Unlike the science images, these have not been PSF-matched. These SW and LW detection
catalogs are subsequently merged into a single, combined catalog. Photometry is
then measured using photutils (L. Bradley et al. 2020) in a range of circular apertures
(–). Photometric uncertainties are estimated by placing random apertures in empty
regions around each source. Unless stated otherwise, we adopt total fluxes measured
within a aperture throughout this work.\r\n\r\n2.2. NIRSpec Observations\r\nGLIMPSE-D
NIRSpec data were obtained during a campaign (DDT #9223; PIs: S. Fujimoto & R. Naidu)
to study a promising Pop III galaxy candidate (S. Fujimoto et al. 2025a). GLIMPSE-D
obtained a total of three G395M/F295LP MSA pointings, totaling 29.78 hr of total
exposure time. The pointing center differed for each of the three configurations
to maximize the total object yield. In total, the GLIMPSE-D sample contains 384
spectra, with depths varying from 9.2 hr to ∼30 hr. All of the planned observations
were successfully executed between 2025 June 30 and July 2. For each MSA configuration,
GLIMPSE-D employed a standard three-point nod pattern at an aperture position angle
PA_V3 = 2705, using 494 groups per integration with the NRSIRS2 readout mode. The
full details of the target selection, prioritization, and MSA planning will be presented
in a forthcoming survey paper (S. Fujimoto et al. 2025b).\r\n\r\n2.3. G395M Data
Reduction and Calibration\r\nThe GLIMPSE-D MSA spectra were uniformly reduced using
msaexp (v0.9.8; G. Brammer 2022). This procedure starts with the level-2 calibrated
products obtained from MAST and applies a number of corrections that include 1/f
noise, artifact detection and removal, and a bias correction in individual exposures
(see J. Rigby et al. 2023 for more details). Together with the JWST pipeline, msaexp
sets the slit World Coordinate System, performs flat-fielding, and computes an initial
pass-loss correction. Each one of the two-dimensional shutters is then drizzled
onto a common pixel grid. Using the standard approach, the background subtraction
is performed locally using stacked, source-free shutters. The one-dimensional spectra
are then obtained via the optimal extraction method (e.g., P. Arrabal Haro et al.
2023; A. de Graaff et al. 2024), in which the center and width of the extraction
“aperture” vary depending on the best-fit Gaussian model (K. Horne 1986), similar
to the methodology widely adopted by a variety of other works (e.g., B. Wang et
al. 2023; J. E. Greene et al. 2024; V. Kokorev et al. 2024b).\r\n\r\nThe absolute
flux calibration of MSA spectra can be influenced by several factors, including
the position of the source within the shutter, calibration and astrometric uncertainties,
and the intrinsic morphology of the source. To correct for these effects and derive
an overall slit-loss correction, we rescale the extracted one-dimensional spectra
by convolving them with all available NIRCam filters and comparing the resulting
flux densities to the total photometry from the GLIMPSE catalog. A wavelength-dependent
correction is then obtained by fitting a second-order polynomial to these differences.\r\n\r\nThe
target in this paper was observed in all three configurations; however, one was
severely contaminated by sources in the same row, making the data recovery for that
configuration unfeasible. Despite this, GLIMPSE-17775 is securely detected in two
configurations (33,262 s and 40,703 s), yielding a total integration time of 20.55
hr. We combine the extracted and separately calibrated one-dimensional spectra using
inverse-variance weighting. The stacked spectrum is shown in Figure 1. We also make
the spectrum publicly available.17\r\n\r\nZoom InZoom OutReset image size\r\nFigure
1. Top: JWST/NIRCam and HST 20 stamps and red, green, blue short-wavelength (SW)
and long-wavelength (LW) color images, comprising the F115W, F150W, and F200W and
F277W, F356W, and F444W bands, respectively. MSA shutters for both configurations
covering GLIMPSE-17775 are shown in blue and red, respectively. The source morphology
is resolved and extended up to ∼2 μm, and then appears to transition to a more PSF-dominated
and compact shape, echoing a growing sample of LRDs with extended rest-UV morphology
(I. Juodžbalis et al. 2024; I. Labbe et al. 2024; J. Matthee et al. 2024; P. Rinaldi
et al. 2025a). This likely hints at the presence of the host galaxy in the filters
covering the rest-UV. In each panel, we show the total AB magnitude as presented
in the GLIMPSE catalog (H. Atek et al. 2025; V. Kokorev et al. 2025). The source
is exceptionally bright (M444 ∼ 23.6) and is detected in most JWST bands at >100σ.
Middle: two-dimensional MSA G395M spectra covering GLIMPSE-17775. Bottom: combined
one-dimensional spectrum (see, e.g., V. Kokorev et al. 2023; A. de Graaff et al.
2025a for the extraction method) of the LRD in the observed frame. We show the data
in black, and the uncertainty as a black shaded region. Fixing the systemic redshift
to the [S iii] λ9071 line (zspec = 3.50102 ± 0.00019), we show the positions and
label the prominent emission with significant (≥3σ) detections as solid vertical
lines. Iron lines are shown separately in green. Due to the sheer number of features,
not all could be labeled; we therefore display all features in Figure 2. Emission
lines for which only upper limits are obtained are shown with dashed lines.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\n3. Emission-line Analysis\r\n3.1.
Spectroscopic Redshift\r\nThe spectrum of GLIMPSE-17775 reveals a remarkably wide
variety of significantly detected emission and absorption lines. Before focusing
on individual features and their complex components, we perform an initial tally
of all detectable lines using a heavily modified version of msaexp (G. Brammer 2022;
V. Kokorev et al. 2024b). The key modifications allow varying the line widths and
fitting multiple components, albeit tied to the same redshift.\r\n\r\nWe fit the
full spectrum using msaexp, adopting Gaussian profiles for emission lines and a
three-segment cubic spline to model the continuum. This minimal spline structure,
appropriate given the high average S/N of GLIMPSE-17775 (≳30), helps prevent overfitting,
particularly of features that may be slightly offset in wavelength or velocity space
from the average redshift. Emission-line positions are fixed; narrow components
are allowed a FWHM between 150 and 800 km s−1, and permitted transitions may include
a broad component (800–5000 km s−1).\r\n\r\nThis yields a redshift of zspec = 3.5010
± 0.0001 (see Table 1). However, several strong lines exhibit significant pixel-level
offsets of 100–200 km s−1 relative to this value. These discrepancies are statistically
robust and appear in both stacked and individual spectra, suggesting that the derived
redshift reflects a weighted average dominated by high-S/N lines. To properly assess
velocity structure, a consistent systemic redshift is required. In the following
sections describing the detailed line analysis, we adopt the centroid of a narrow
forbidden line as the systemic reference frame (specifically [S iii] λ9071; see
Section 3.3).\r\n\r\nUsing the updated redshift alongside the strong-lensing model
of AS1063 (A. Zitrin et al. 2015; L. Furtak et al. 2026, in preparation), we recalculate
the lensing magnification to be μ = 2.04 ± 0.21, consistent with previous estimates
based on zphot. With redshift and magnification now fixed, we turn to a deeper analysis
of the emission-line properties.\r\n\r\n3.2. Line Identification\r\nBeyond velocity
offsets, the initial msaexp fit highlights several notable features. Broad hydrogen
lines, ubiquitous in LRDs (e.g., D. D. Kocevski et al. 2023; V. Kokorev et al. 2023;
L. J. Furtak et al. 2024; J. Matthee et al. 2024; A. de Graaff et al. 2025b; R.
E. Hviding et al. 2025; R. P. Naidu et al. 2025; A. J. Taylor et al. 2025), are
strongly favored across the Balmer and Paschen series, with Δχ2 > 10. These include
Hα and Pa10 through Paγ. Although Paβ falls near the edge of the detector, we nonetheless
observe a prominent broad wing at its expected location (see Figure 1).\r\n\r\nBroad
components are also detected in several helium and oxygen lines: He i λ6680, He
i λ7065, O i λ8448, He i λ10830, and O i λ11290. Notably, the He i λ10830 line shows
a classic P-Cygni profile with a clear blueshifted absorption trough. While Balmer
absorption is becoming a familiar sight in LRDs (R. Maiolino et al. 2024; J. Matthee
et al. 2024; A. de Graaff et al. 2025b; D. D. Kocevski et al. 2025; R. P. Naidu
et al. 2025), helium absorption remains rare, with only a few published cases at
high z (e.g., I. Juodžbalis et al. 2024; R. P. Naidu et al. 2024; B. Wang et al.
2025). Curiously, this was also recently reported in local analogs of LRDs (X. Lin
et al. 2026).\r\n\r\nThe most striking feature is the detection of an extensive
Fe ii emission forest in the rest-NIR—at least 16 distinct features are identified
by msaexp and highlighted in green in Figure 1. Previous detections of permitted
Fe ii in LRDs have been mostly limited to rest-UV/optical wavelengths using low-resolution
PRISM spectra (R. Tripodi et al. 2025), with only few examples in the NIR (e.g.,
see broad Fe iiλ9200 I. Labbe et al. 2024). Iron has also been identified in local
LRD analogs (X. Lin et al. 2026; X. Ji et al. 2026). Only recently have a few Fe
ii emitters been reported in medium-resolution (F. D’Eugenio et al. 2025) and high-resolution
spectra (A. Torralba et al. 2026). The richness of these lines in GLIMPSE-17775
hints at a dense, partially shielded gas phase, where processes such as Lyβ fluorescence
and continuum pumping may be enhancing Fe ii emission (T. A. A. Sigut & A. K. Pradhan
1998, 2003; T. A. A. Sigut et al. 2004), offering a new diagnostic window into early
AGN environments.\r\n\r\nIn summary, GLIMPSE-17775 exhibits an exceptionally rich
and kinematically complex array of emission and absorption features. While the initial
msaexp modeling provides a solid foundation for redshift estimation and line identification,
it lacks the flexibility to capture the full diversity of line profiles in this
high-S/N dataset. In the following sections, we peel back the spectral layers with
increasing precision.\r\n\r\n3.3. Line Fitting\r\nThe exceptional depth of the G395M
spectrum for GLIMPSE-17775 enables detailed modeling of both multiple kinematic
components and potential velocity offsets between line species. Unless noted otherwise,
each line is fit with a single Gaussian narrow component (FWHM = 100−800 km s−1).
For permitted lines flagged by msaexp as potentially broad, we follow the approach
of V. Rusakov et al. (2026) and model the profile as an intrinsic Gaussian core
broadened by electron scattering, implemented via convolution with an exponential-wing
component. The intrinsic Gaussian FWHM is allowed to vary between 500 and 5000 km
s−1. The characteristic scattering width (i.e., the strength of the exponential
wings, W) is treated as a free parameter and is allowed to vary independently between
different transitions. For each broad line, we also perform an alternative fit with
the W parameter fixed to zero (pure Gaussian) and compare the resulting goodness
of fit to assess whether the exponential wings are statistically required. Line
centers are allowed to vary independently unless otherwise specified.\r\n\r\nAbsorption
lines are modeled using a Gaussian optical-depth profile, where the observed flux
is Fobs = Fem e−τ(λ), where . The free parameters are then the central optical depth
τ0, velocity width Δvabs, and redshift zabs (see I. Juodžbalis et al. 2024). Widths
and redshifts (for both narrow and broad components) are typically free, with redshift
limited to ± 0.1 from the msaexp value. Local continua are fit using first-order
polynomials.\r\n\r\nAll individual model components are first initialized and coadded
on an oversampled wavelength grid. To take into account the wavelength-dependent
resolution of the grating, we interpolate our model onto a variable step grid while
making sure that the total integrated flux is preserved. Further, we increase the
nominal spectral resolution by a factor of 1.7, as it has been shown that the spectral
resolution for a pointlike source falling within a shutter is higher than that of
a uniformly illuminated slitlet (A. de Graaff et al. 2024). Fitting uses nonlinear
χ2 minimization, with uncertainties derived from multivariate resampling of the
covariance matrix.\r\n\r\nTable 1. Source Properties\r\n\r\nParametera\tGLIMPSE-17775\r\nID\t17775\r\nR.A.
[deg]\t342.20080\r\nDecl. [deg]\t–44.54366\r\nzphot (eazy)\t4.2 ± 0.1\r\nzspec ([S
iii] λ9071)\t3.50102 ± 0.00019\r\nμ\t2.04 ± 0.21\r\nMUV [AB mag]\t−17.27 ± 0.05\r\nreff,UV
[pc]\t1000 ± 200\r\nreff,opt [pc]\t<300\r\nβ\t–0.69 ± 0.12\r\nlog10(MBH/M⊙)\t6.65
± 0.15\r\nLbol [erg s−1]\t(1.06 ± 0.14)×1045\r\nλedd\t1.86 ± 0.25\r\nlog10(M*/M⊙)\t<7.5\r\nAV\t0.1
± 0.3\r\nfν,4050Å/fν,3670Å\t2.02 ± 0.10\r\nNote. aPhysical parameters are corrected
for the lensing magnification.\r\n\r\nDownload table as: \r\nASCIITypeset image\r\n\r\nGiven
the complexity, the spectrum is divided into six windows grouped by line species
or proximity (see Figure 2). Below, we describe the assumptions adopted for each
window. Final fluxes and equivalent widths of the narrow and broad lines are listed
in Tables 2 and 3, respectively, while kinematics are reported in Tables 4 and 5.
We show detailed line fits in Figure 2.\r\n\r\nZoom InZoom OutReset image size\r\nFigure
2. A staggering abundance of spectral lines in GLIMPSE-17775 at z = 3.501. For each
spectral window defined in Section 3.3, we show the data (black), the best-fit narrow
and broad components (dark purple and blue), and the total best-fit model including
the continuum (red). All broad components were fit with models allowing exponential
wings. The ΔBIC between exponential and Gaussian fits is reported in the top right
of each panel; negative values indicate a preference for an exponential profile.
The lower panels display the uncertainty-weighted residuals for each fit.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\nTable 2. Fluxes of Narrow
Emission Lines and Their Rest-frame Equivalent Widthsa\r\n\r\nLine\tλrest\tFlux\tEW0\r\n
\t(Å)\t(10−20 erg s−1 cm−2)\t(Å)\r\nNarrow Emission Lines\r\nO i\t6302.0\t54.0 ±
21.2\t3.3 ± 1.2\r\n[N ii]\t6549.0\t25.6 ± 10.3\t1.6 ± 0.7\r\nHα\t6562.8\t2622.9
± 200.7\t167.7 ± 12.8\r\n[N ii]\t6584.0\t77.1 ± 37.1\t4.9 ± 1.6\r\nHe i\t6680.0\t14.7
± 11.1\t0.8 ± 0.7\r\n[S ii]\t6717.0\t22.2 ± 0.1\t1.5 ± 0.7\r\n[S ii]\t6731.0\t21.4
± 0.1\t1.4 ± 0.5\r\nHe i\t7065.0\t461.7 ± 210.2\t31.0 ± 12.2\r\n[Ar iii]\t7138.0\t12.6
± 3.4\t1.0 ± 0.3\r\nFe ii\t7156.0\t26.2 ± 7.2\t1.8 ± 0.2\r\n[O ii]\t7323.0\t26.0
± 23.0\t1.7 ± 1.5\r\n[O ii]\t7325.0\t16.9 ± 1.8\t1.2 ± 0.1\r\n[O ii]\t7332.0\t26.2
± 9.1\t1.8 ± 0.6\r\nFe ii\t8228.0\t23.7 ± 4.2\t2.0 ± 0.3\r\nFe ii\t8239.0\t7.2 ±
4.0\t0.6 ± 0.3\r\nFe ii\t8289.0\t6.3 ± 3.7\t0.5 ± 0.3\r\nFe iii\t8306.0\t5.7 ± 3.6\t0.5
± 0.3\r\nO i\t8448.0\t67.6 ± 2.4\t6.1 ± 1.3\r\nFe ii\t8470.0\t16.2 ± 5.0\t1.4 ±
0.4\r\nFe ii\t8490.0\t26.7 ± 4.3\t2.4 ± 0.4\r\nPa10\t9015.0\t16.5 ± 5.0\t1.8 ± 0.5\r\n[S
iii]\t9071.0\t27.2 ± 2.3\t3.5 ± 0.3\r\nFe ii\t9075.0\t30.0 ± 4.7\t3.4 ± 0.5\r\nFe
ii\t9125.0\t16.8 ± 5.2\t1.9 ± 0.6\r\nFe ii\t9134.0\t36.9 ± 5.0\t4.1 ± 0.6\r\nFe
ii\t9179.0\t95.0 ± 5.5\t10.6 ± 0.6\r\nFe ii\t9204.0\t50.1 ± 6.1\t5.6 ± 0.7\r\nPa9\t9229.0\t19.4
± 7.0\t2.2 ± 0.8\r\nFe ii\t9394.0\t17.3 ± 3.9\t2.0 ± 0.5\r\n[S iii]\t9533.0\t84.7
± 5.9\t10.2 ± 0.7\r\nPa8\t9545.0\t44.8 ± 11.3\t5.4 ± 1.4\r\nFe ii\t9997.0\t29.5
± 4.5\t3.8 ± 0.6\r\nPaδ\t10049.0\t104.2 ± 12.2\t13.7 ± 1.7\r\nFe ii\t10490.0\t8.0
± 2.7\t1.1 ± 0.4\r\nFe ii\t10501.0\t24.4 ± 5.9\t3.1 ± 0.8\r\nHe i\t10830.0\t163.0
± 96.0\t22.6 ± 13.3\r\nPaγ\t10938.0\t146.3 ± 25.5\t20.9 ± 3.8\r\nFe ii\t11128.0\t12.3
± 3.7\t1.8 ± 0.6\r\nO i\t11290.0\t49.2 ± 4.1\t7.7 ± 2.3\r\nNote. aNot corrected
for lensing magnification.\r\n\r\nDownload table as: \r\nASCIITypeset image\r\n\r\nTable
3. Fluxes of Broad Emission Lines and Their Rest-frame Equivalent Widthsa\r\n\r\nLine\tλrest\tFlux\tEW0\r\n
\t(Å)\t(10−20 erg s−1 cm−2)\t(Å)\r\nBroad Emission Lines\r\nHα\t6562.8\t14803.5
± 198.6\t946.3 ± 15.6\r\nHe i\t6680.0\t144.6 ± 44.7\t9.4 ± 2.9\r\nHe i\t7065.0\t824.2
± 210.0\t55.4 ± 15.1\r\nPa10\t9015.0\t53.7 ± 11.1\t5.8 ± 1.3\r\nPa9\t9229.0\t119.0
± 13.5\t13.6 ± 1.5\r\nPa8\t9545.0\t191.2 ± 17.0\t23.1 ± 2.1\r\nPaδ\t10049.0\t370.6
± 15.0\t48.8 ± 2.3\r\nHe i\t10830.0\t2294.9 ± 212.6\t318.8 ± 30.3\r\nPaγ\t10938.0\t652.3
± 14.0\t92.9 ± 2.4\r\nO i\t8448.0\t93.7 ± 7.9\t8.4 ± 0.7\r\nO i\t11290.0\t106.2
± 63.9\t16.6 ± 10.4\r\nNote. aNot corrected for lensing magnification.\r\n\r\nDownload
table as: \r\nASCIITypeset image\r\n\r\nTable 4. Kinematic Properties of Narrow
Lines\r\n\r\nLine\tλrest\tFWHM\tΔv\r\n \t(Å)\t(km s−1)\t(km s−1)\r\nNarrow Emission
Lines\r\n[O i]\t6300.3\t455 ± 175\t−101 ± 81\r\nHα\t6562.8\t304 ± 8\t+145 ± 13\r\n[N
ii]\t6583.4\t347 ± 117\t+84 ± 47\r\n[S ii]\t6716.4\t232 ± 62\t+82 ± 33\r\n[S ii]\t6731\t232
± 62\t+82 ± 33\r\nHe i\t6678.2\t87 ± 14\t+40 ± 14\r\nHe i\t7065.2\t408 ± 644\t+112
± 396\r\n[Ar iii]\t7135.8\t89 ± 50\t−26 ± 20\r\nFe ii\t7155.2\t96 ± 50\t+15 ± 15\r\n[O
ii]\t7320.0\t400 ± 120\t−37 ± 72\r\nFe ii\t8228.0\t290 ± 48\t+21 ± 5\r\nFe ii\t8239.0\t290
± 48\t+21 ± 5\r\nFe ii\t8289.0\t290 ± 48\t+21 ± 5\r\nFe iii\t8306.0\t290 ± 48\t+21
± 5\r\nO i\t8446.4\t235 ± 30\t−43 ± 19\r\nFe ii\t8470.0\t290 ± 48\t+21 ± 5\r\nFe
ii\t8490.0\t290 ± 48\t+21 ± 5\r\nPa10\t9014.9\t259 ± 36\t−46 ± 19\r\n[S iii]\t9071.0\t230
± 13\t⋯\r\nFe ii\t9075.0\t486 ± 24\t−21 ± 17\r\nFe ii\t9125.0\t486 ± 24\t−21 ± 17\r\nFe
ii\t9134.0\t486 ± 24\t−21 ± 17\r\nFe ii\t9179.0\t486 ± 24\t−21 ± 17\r\nFe ii\t9204.0\t486
± 24\t−21 ± 17\r\nPa9\t9229.0\t259 ± 35\t−46 ± 19\r\nFe ii\t9394.0\t486 ± 24\t−21
± 17\r\nPa8\t9545.6\t259 ± 36\t−46 ± 19\r\n[S iii]\t9533\t230 ± 13\t+23 ± 13\r\nFe
ii\t9997.0\t331 ± 55\t+90 ± 25\r\nPaδ\t10049.4\t332 ± 22\t+21 ± 15\r\nHe i\t10830.3\t287
± 46\t+112 ± 26\r\nPaγ\t10938.1\t267 ± 25\t+26 ± 17\r\nFe ii\t10490.0\t332 ± 96\t+44
± 43\r\nFe ii\t10501.0\t332 ± 96\t+44 ± 43\r\nFe ii\t11128.0\t153 ± 116\t+37 ± 30\r\nO
i\t11290.0\t260 ± 58\t−33 ± 24\r\nNote. Velocity offsets (Δv) calculated relative
to [S iii] λ9071 at z = 3.50102.\r\n\r\nDownload table as: \r\nASCIITypeset image\r\n\r\nTable
5. Kinematic Properties of Broad and Absorption Lines\r\n\r\nLine\tλrest\tFWHM\tW\tΔv\r\n
\t(Å)\t(km s−1)\t(km s−1)\t(km s−1)\r\nBroad Emission Lines\r\nHα\t6562.8\t1024
± 21\t3010 ± 450\t−7 ± 16\r\nHe i\t6678.2\t1041 ± 792\t3890 ± 2083\t−137 ± 151\r\nHe
i\t7065.2\t473 ± 116\t1000 ± 600\t−136 ± 82\r\nO i\t8446.4\t562 ± 331\t1120 ± 590\t+39
± 80\r\nPa10\t9014.9\t766 ± 202\t2100 ± 600\t−155 ± 39\r\nPa9\t9229.0\t766 ± 202\t2100
± 600\t−155 ± 39\r\nPa8\t9545.6\t766 ± 202\t2100 ± 600\t−155 ± 39\r\nPaδ\t10049.4\t1672
± 458\t3500 ± 400\t+23 ± 44\r\nHe i\t10830.3\t536 ± 45\t2760 ± 220\t+154 ± 22\r\nPaγ\t10938.1\t1035
± 322\t2400 ± 260\t−75 ± 31\r\nO i\t11287.0\t1188 ± 1099\t4300 ± 2000\t+245 ± 214\r\nAbsorption
Lines\r\nHα\t6562.8\t1000 ± 123\t⋯\t−200 ± 32\r\nHe i\t7065.2\t587 ± 1024\t⋯\t−52
± 83\r\nHe i\t10830.3\t794 ± 21\t⋯\t+45 ± 22\r\nNote. Velocity offsets (Δv) calculated
relative to [S iii] λ9071 at z = 3.50102.\r\n\r\nDownload table as: \r\nASCIITypeset
image\r\n\r\n3.3.1. Hα Complex\r\nHα is modeled with independent narrow, broad,
and absorption components. [O i] λ6302 and He i λ6680 are modeled with narrow and
broad profiles. [N ii] lines are fixed at a 1:3 ratio and share kinematics; [S ii]
lines have independent amplitudes but tied velocities and widths.\r\n\r\nWe find
that broad Hα and He i λ6680 are strongly favored to have exponential wings (ΔBIC
∼ −500), yielding a FWHM (of the intrinsic Gaussian core) of ∼1000 km s−1—significantly
narrower than the ∼3000 km s−1 derived from pure Gaussians. Although no distinct
Hα absorption component is explicitly detected, likely due to insufficient resolution,
the overall asymmetry of the line is best reproduced when a weak, blueshifted absorber
is included in the fit. This may indicate subtle self-absorption or partial obscuration
within the dense cocoon. We return to the implications of this profile shape later.\r\n\r\n3.3.2.
He i λ7065\r\nThe He i λ7065 line shows a prominent blueshifted absorption component.
We fit it with narrow, broad, and absorption profiles. The rest of the lines, including
[Ar iii] λ7138, Fe ii λ7156, and the [O ii] triplet (λλ7323, 7325, 7332), are modeled
as independent narrow lines.\r\n\r\nHe i λ7065 shows a strong preference for an
exponential profile (ΔBIC ∼ − 16) with a FWHM = 473 ± 116 km s−1. A residual bump
spanning from ∼λ7290 to λ7320 is likely a combination of multiple Fe ii, such as
λ7290, λ7308, and potentially Fe iii λ7319.65 lines. Curiously, the latter line
is often labeled as “hazy” in various emission-line libraries (e.g., A. Kramida
et al. 2024), reflecting its undefined shape as a result of pressure broadening
or scattering in very dense gas.\r\n\r\n3.3.3. O i λ8448 and Iron Lines\r\nIn this
part of the spectrum the O i λ8448 is fit with narrow and broad components. All
of the iron lines, including Fe ii λλ8228, 8239, 8289, 8470, 8490 as well as a potential
Fe iii λ8306, are fit as narrow lines with shared kinematics. O i components are
fit independently.\r\n\r\nWe find that the broad O i component is best described
by a standard Gaussian profile, with a stronger statistical preference over exponential
wings (ΔBIC ∼ 4). However, we caution that a trough at ∼3.77 μm, likely an artifact,
may affect the reliability of the fit in this region.\r\n\r\n3.3.4. Iron Forest
and Paschen Lines\r\nThis spectral region is among the most complex, due to the
dense clustering of emission features. The Paschen lines Pa10–Pa8 are modeled with
narrow and broad components. To reduce the number of free parameters, we tie all
narrow Paschen components together kinematically, and do the same for the broad
components. Fe ii λλ9075, 9125, 9134,9179, 9204, 9394 are fit with a shared centroid
and width. [S iii] lines are fit independently.\r\n\r\nThe [S iii] λ9071 line is
used to define the systemic redshift: z = 3.50102 ± 0.00019. This is done because
forbidden lines, such as [S iii] or [O iii], have lower critical densities that
are incompatible with the dense-gas envelopes giving rise to the other lines we
observe. These lines may instead come from the host galaxy itself (e.g., R. Maiolino
et al. 2024), and we therefore choose this line to define the overall redshift of
the system and to measure all the offsets relative to it. All velocity offsets discussed
in the subsequent sections are computed relative to this reference frame. The Paschen
lines show strong preference for exponential wings (ΔBIC ∼ −38), with a FWHM = 766
± 202 km s−1—narrower than Hα, but consistent within 2σ.\r\n\r\n3.3.5. Paδ\r\nThe
Fe ii λ9997 and Paδ complex is modeled with an independent narrow component for
Fe ii and both narrow and broad components for Paδ. There is no evidence for absorption.
Exponential wings are again preferred (ΔBIC ∼ −26). The resulting FWHM of 1672 ±
458 km s−1 is notably larger than those of both higher-order Paschen lines and Hα,
though still consistent with the latter within 2σ. It is also possible that the
line shape is impacted by Fe ii λ9997 and the undetected (but likely present) Fe
ii λλ10131, 10173 lines.\r\n\r\n3.3.6. He i λ10830 and Paγ\r\nThe final window contains
a complicated blend of broad He i λ10830 and Paγ lines, with a clear blueshifted
absorption in the former. We fit three components (narrow, broad, and absorption)
to He iλ10830 and narrow plus broad components to Paγ, keeping everything kinematically
independent. We fit narrow Fe ii lines at 10490, 10501, and 11128 Å with fixed redshift
and line width. Finally, O i λ11290 is fit with independent narrow and broad components.
Exponential wings are again preferred over a pure Gaussian profile.\r\n\r\n4. Data
Analysis\r\n4.1. Morphology\r\nLRDs are unresolved in the rest-optical by definition,
with measured sizes consistent with the PSF HWHM ( in F444W), and in some cases
even smaller when dithers align favorably (e.g., I. Labbé et al. 2025). Gravitational
lensing can further push constraints on their intrinsic sizes to ≲100 pc (L. J.
Furtak et al. 2024).\r\n\r\nIn the rest-UV, however, a more complex picture is emerging.
Several studies have now reported faint, extended, asymmetric components adjacent
to the compact core (V. Kokorev et al. 2024b; I. Labbe et al. 2024; J. Matthee et
al. 2024; P. Rinaldi et al. 2025a, 2025b), often suppressed by surface-brightness
dimming. As shown in Figure 1, GLIMPSE-17775 likewise consists of two components
out to F200W (rest ∼ 4000 Å), coincident with the Balmer break. However, we note
that the break itself is much weaker than found in objects with very similar spectra
(e.g., B. Wang et al. 2024; see Figure 3). At longer wavelengths, a point-source
(PS) morphology dominates, consistent with a black-hole-dominated core. To quantify
this transition, we model the NIRCam imaging using PYSERSIC (I. Pasha & T. B. Miller2023)
with a minimal configuration: a fixed-center PS plus a freely offset Sérsic profile.
Normalizations, n, and reff are all allowed to vary, and uncertainties are drawn
from the Markov Chain Monte Carlo posteriors (e.g., V. Kokorev et al. 2024a).\r\n\r\nZoom
InZoom OutReset image size\r\nFigure 3. The diversity of Balmer breaks in LRDs.
The black points show the HST and JWST GLIMPSE photometry of GLIMPSE-17775. The
blue line shows best-fit EAZY SED fit to the photometry only, fixing the redshift
to the zspec. The maroon line show the combined and photometry-corrected G395M spectrum.
While the red color in F200W–F277W is partially influenced by a bright Hα line,
the Balmer break between F150W and F200W is still prominent. We further show spectra
of various other LRDs (I. Labbe et al. 2024; B. Wang et al. 2024; A. de Graaff et
al. 2025b; R. P. Naidu et al. 2025; A. J. Taylor et al. 2025), all shifted to z
= 3.501 and normalized at 5100 Å. Finally, we show HST (blue) and JWST (orange)
filter transmission curves below.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\nOur fits show that the host galaxy dominates up to λrest ∼ 4000 Å, where
the host and nucleus contribute roughly equally, beyond which the PS prevails to
λrest ∼ 1 μm. Because the NIRCam LW detector has ≳2× poorer resolution than the
SW, a clean separation of host and nucleus in the rest-optical is impractical (see,
e.g., K. E. Whalen et al. 2026). Fortunately, F200W lies at the transition where
both the resolution and flux ratio are favorable, so we use that band to illustrate
our galaxy/LRD decomposition. We illustrate this in Figure 4, which also shows the
increasing PS fraction with wavelength, while acknowledging the uncertainties at
longer wavelengths.\r\n\r\nZoom InZoom OutReset image size\r\nFigure 4. Top: two-component
Sérsic+point-source (PS) fit to the F200W morphology of GLIMPSE-17775. Panels show,
from left to right, the data, best-fit model, model with the extended component
removed, and residuals. Bottom: fractional PS contribution vs. rest-frame wavelength.
Shaded regions mark SW (blue) and LW (red) detectors, where the lower resolution
of LW filters hinders reliable two-component decomposition.\r\n\r\nDownload figure:\r\n\r\nStandard
imageHigh-resolution image\r\nAfter applying the lensing correction, we find that
the extended component dominating the UV light has a radius of reff ∼ 1000 pc, whereas
the actual compact LRD, dominant in the rest-optical, is fully consistent with the
PSF and reff < 300 pc.\r\n\r\n4.2. Dust Attenuation\r\nThe ratio between observed
emission-line fluxes is commonly used to estimate dust extinction. For LRDs, this
has typically been achieved through the Balmer decrement, provided that multiple
Balmer lines are available. In our case, only Hα is detected. While the Paschen
series, of which five lines are observed, could, in principle, be used to estimate
extinction, the likely presence of stratified dense gas in LRDs (A. de Graaff et
al. 2025b; R. P. Naidu et al. 2025) implies that the intrinsic line ratios may deviate
significantly from standard Case B recombination expectations (S.-J. Chang et al.
2026). Further, at the wavelengths of the Paschen series, the attenuation curves
are practically flat (e.g., D. Calzetti et al. 2000). Small offsets of the Case
B ratios would have a significant effect on the derived dust attenuation, but in
return require extreme precision on measured line fluxes to be meaningful. Our uncertainties
on, e.g., Paγ/Paδ are small, roughly 10%–15%, yet this still leads to an impractically
high uncertainty on AV. To circumvent this limitation, we instead employ the ratio
between the permitted O i λ8448 and O i λ11290 lines.\r\n\r\nThese transitions share
a common energy level, and under the assumption of Bowen (Lyβ) fluorescence, all
transitions through the λ11290 transition also cascade through the λ8448. This makes
their intrinsic intensity set solely by the ratio of the inverse of their wavelengths.\r\n\r\nTo
ensure we are comparing the same physical gas component, we isolate the narrow emission
peaks in both transitions, which show consistent widths of FWHM ∼ 250 km s−1. This
similarity supports the use of their flux ratio as a dust probe. We adopt the Small
Magellanic Cloud (SMC) attenuation curve (K. D. Gordon et al. 2003), widely used
for high-redshift galaxies and reddened AGN (P. F. Hopkins et al. 2004; P. L. Capak
et al. 2015; N. A. Reddy et al. 2015, 2018; V. Kokorev et al. 2023; A. J. Taylor
et al. 2025). Assuming an intrinsic ratio of (8448/11290)int = 1.336 (D. E. Osterbrock1989),
we infer AV = 0.1 ± 0.3 mag, consistent with negligible extinction.\r\n\r\nWe caution,
however, that this ratio probes only the narrow-line-emitting gas, which could originate
either in the host galaxy or within a narrow-line region associated with the AGN.
If the latter is the case, then the red optical continuum slope (βopt ∼ 0.35) would
suggest that the observed SED is intrinsically red rather than reddened by dust.
If instead the narrow lines arise predominantly in the host galaxy, this constraint
does not directly inform the origin of the continuum emission. Similar Case B–consistent
narrow-line ratios have been reported in other LRDs (e.g., M. Brooks et al. 2025;
G. P. Nikopoulos et al. 2025), where the broad lines were found to show significant
departures from Case B.\r\n\r\nAlthough the wavelength coverage of the red grating
does not allow a Balmer decrement test for the broad-line emission (only Hα is detected),
we can perform a consistency check using the brightest broad Paschen lines (Paγ,
Paδ, and Pa8). Adopting intrinsic Case B ratios from P. J. Storey & D. G. Hummer
(1995; Paγ/Paδ ≃ 1.5 and Paδ/Pa8 ≃ 1.8), and comparing these to our measured values
of Paγ/Paδ = 1.77 ± 0.15 and Paδ/Pa8 = 1.94 ± 0.20, we find the broad Paschen lines
to be consistent with Case B within ≃2σ, particularly when systematic uncertainties
from blending and profile decomposition are taken into account. If Case B is applicable
in the dense environments surrounding the central AGN, this would be consistent
with a low-dust or dust-free origin for the broad-line-emitting gas.\r\n\r\n5. Line
Properties\r\nOur fitting procedure yields over 40 emission and absorption features,
most of which are detected at a high (S/N> 3) significance. With all the pieces
in place, we now comment on the line profiles, kinematics, and the specific line
species that we identify.\r\n\r\n5.1. Exponential Wings\r\nAs already noted throughout
Section 4, and further highlighted in Figure 2, all permitted lines in the spectrum,
with the exception of O iλ8448, which is likely impacted by data-quality issues,
are better fit when the broad component is convolved with an exponential profile.
The statistical preference for this model (as measured by ΔBIC) is especially strong
for our brightest line, Hα. To further demonstrate this, and to compare this fit
with a more standard, Gaussian-only approach, we show both models in Figure 5. When
the broad line is fit using only a Gaussian profile, large portions of the line
are underfit at a ≳3σ significance level, whereas a model that includes exponential
wings shows a much smoother, albeit not perfect, residual plot.\r\n\r\nZoom InZoom
OutReset image size\r\nFigure 5. Exponential wings are required. Comparison of a
Gaussian×exponential model (red) and a single Gaussian profile (blue) for Hα. Uncertainties
are shown as vertical lines in each spectral bin, although they are too small to
be visible. The exponential model provides a far superior fit, with smoother residuals
and a strongly preferred ΔBIC, highlighting the necessity of exponential wings to
capture the broad-line shape.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\nThis strong preference for exponential wings is consistent with expectations
from electron scattering in dense, ionized gas. Unlike Gaussian profiles, which
arise from Doppler broadening due to thermal and bulk motions around the supermassive
black hole, exponential profiles arise in environments dominated by electron scattering
(e.g., S.-J. Chang et al. 2026; V. Rusakov et al. 2026). The absence of strong broadening
in the forbidden lines (e.g., [S ii], [S iii], and [N ii]) already suggests that
the densities where these electron-scattered profiles originate must already exceed
multiple times the critical densities of these transitions (ne > 106). Combined
with the fact that these broad profiles are non-Gaussian in shape, both the likely
volume and column densities are likely even higher, at ne = 108 cm−3 and Ne ∼ 1024
cm−2, respectively, as suggested by both K. Inayoshi & R. Maiolino (2025) and V.
Rusakov et al. (2026).\r\n\r\nRecent work (e.g., M. Brazzini et al. 2025) argues
that, in classical broad-line region (BLR) environments, an electron-scattering
origin for broad wings requires similar intrinsic and scattering widths across recombination
lines. We therefore examine these criteria for the hydrogen transitions and find
that, within the uncertainties of our fits, both the intrinsic and exponential widths
are broadly comparable among the recombination lines. However, unlike classical
BLRs, LRDs are expected to be strongly stratified, with different recombination
transitions forming at different depths and probing different effective electron
columns (e.g., A. de Graaff et al. 2025d; A. Sneppen et al. 2026). In such a structure,
strict equality of widths is not expected even if a common scattering kernel shapes
the wings. The modest variations observed here are therefore consistent with electron
scattering in a dense, stratified cocoon.\r\n\r\nIt is important to note that such
detailed profile decomposition is only possible due to the exceptionally high S/N
per pixel achieved in the line wings of our NIRSpec G395M spectrum. As emphasized
in V. Rusakov et al. (2026), these features would be impossible to distinguish with
shallower data or lower-resolution modes such as NIRSpec/PRISM, or even G395M exposures
lacking comparable depth.\r\n\r\n5.2. Line Profiles\r\nFurther, in Figure 6, we
compare the best-fit models for all broad lines. As noted previously, with the exception
of O i λ8448, every broad line is better described by exponential wings, resulting
in very similar overall line shapes. The main differences arise in their widths.\r\n\r\nZoom
InZoom OutReset image size\r\nFigure 6. Best-fit profiles of all broad lines, oversampled
and shifted to a common center. The top panel shows hydrogen recombination (Hα,
black, and Paschen series), the middle panel shows O i, and the bottom panel shows
He i. Shaded regions indicate 1σ uncertainties for the least-constrained lines (Paδ,
O i λ11290, and He i λ6680); uncertainties for the remaining lines are omitted for
clarity. We note that hydrogen and O i lines show largely similar widths, consistent
with their coupling through charge exchange. By contrast, He i lines are systematically
narrower, likely reflecting their distinct metastable triplet physics and formation
in a less dense outer region.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\nDespite some fits having sizable uncertainties, a trend emerges across
line species. Hydrogen recombination lines (with the exception of Paδ) and O i transitions
consistently show comparable intrinsic FWHM values of ∼800 km s−1. This agreement
is not coincidental. Neutral oxygen and ionized hydrogen have nearly identical ionization
potentials, enabling rapid charge-exchange coupling between O+ + H0⇌ O0 + H+ (D.
E. Osterbrock & G. J. Ferland 2006). This continual electron exchange tightly locks
the spatial distribution, ionization state, and kinematics of neutral oxygen to
ionized hydrogen (and vice versa), so their broad-line profiles are naturally expected
to track one another. The observed similarity therefore provides an important consistency
check, reinforcing that the O i emission originates in the same dense, ionized gas
as the hydrogen recombination lines. In contrast, the Fe ii lines exhibit significantly
narrower widths, matching the narrow cores of the permitted transitions rather than
their exponential wings. This implies that the Fe ii emission arises in a cooler,
less turbulent zone exterior to the scattering-dominated region, but still closely
coupled to the AGN continuum source.\r\n\r\nBy contrast, He i emission is systematically
narrower. He i lines such as λ7065 and λ10830 do not couple to hydrogen via charge
exchange, and their lower metastable level (23S) has distinct population physics,
being fed by both collisional and recombination pathways. Further, one has to take
into account the radiative-transfer effects, which make it possible to radiatively
excite metastable ground-state electrons. As a result, He i emission may arise from
a somewhat different spatial or kinematic region than H and O. We return to this
point in more detail below.\r\n\r\nTaken together, the similar FWHM of hydrogen
and oxygen broad-line profiles, combined with the near-universal exponential wings
seen across all permitted transitions, strongly suggests that the line shapes are
set by a common, line-independent scattering kernel rather than by transition-specific
processes. Electron (Thomson) scattering in a dense, ionized cocoon provides a natural
explanation: It produces exponential wings of nearly identical form across species,
with widths set primarily by the electron temperature and column density (typically
∼1024 cm−2), and leaves only secondary variations from species-specific excitation
or optical-depth effects (e.g., S.-J. Chang et al. 2026; V. Rusakov et al. 2026).
In this framework, the narrower He i lines reflect stratification within the cocoon,
where He i emission arises from an outer region that has a lower density, temperature,
or column density, while the bulk hydrogen and oxygen emission share a common kinematic
imprint within an inner, denser region.\r\n\r\n5.3. Line Kinematics\r\nBefore we
proceed to discussing the individual features in more detail, we would like to comment
on the systematic velocity offsets between various line species in the spectrum
of GLIMPSE-17775. As mentioned previously, we choose the redshift of the narrow
forbidden [S iii] λ9701 as the systemic reference, due to it being relatively bright
and isolated. We place all velocity offsets in context by plotting all values from
Tables 4 and 5 in Figure 7.\r\n\r\nZoom InZoom OutReset image size\r\nFigure 7.
Velocity offsets (relative to [S iii]λ9071) and FWHM for all detected lines. Narrow
permitted lines are shown as maroon circles (open for forbidden), broad lines as
blue, absorption as gold, and Fe ii lines as green diamonds. The shaded band marks
the velocity uncertainty set by the median spectral resolution. Narrow lines align
closely with the systemic redshift, while absorption features show moderate blueshifts
of ∼150 km s−1.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution image\r\nWhile
every fit formally yields a centroid, the significance of any offset is constrained
by the spectral resolution and S/N of the data. To gauge which velocity shifts are
meaningful, we adopt a conservative uncertainty of ΔV ∼ med(R)/5, with R = λ/Δλ.
This corresponds to ∼60 km s−1, below which offsets are unlikely to be statistically
significant.\r\n\r\nQualitatively, we do not find systematic shifts of either permitted
or forbidden narrow lines relative to the systemic redshift. Iron lines also appear
consistent with the systemic velocity. In contrast, the permitted broad lines, together
with their associated absorption components, show a consistent blueshift of order
∼100 km s−1.\r\n\r\nSuch blueshifts are commonly interpreted as signatures of outflowing
gas in the BLR, where scattering and absorption occur preferentially along outflowing
sight lines. In the context of GLIMPSE-17775, this modest but systematic offset
strengthens the case for a stratified cocoon, while the narrow lines trace gas in
the outer regions at systemic velocity, the BLR and absorbing layers appear to be
participating in bulk outflows. Confirming the detailed velocity structure, however,
will require higher-resolution follow-up with the NIRSpec H-gratings (e.g., A. Saldana-Lopez
et al. 2025; A. Torralba et al. 2026).\r\n\r\n5.4. Hydrogen Absorption Lines\r\nAlthough
no strong hydrogen absorption lines are explicitly detected, the Hα profile (Figure
2) shows a noticeable asymmetry, with suppressed flux on the blue side of the line.
This feature is best modeled by a blueshifted (∼−200 km s−1) absorption component,
as already noted in Section 4. Similar nonresonant absorption signatures (e.g.,
Balmer lines) are now routinely observed in LRDs across a wide range of redshifts
(e.g., J. E. Greene et al. 2024; V. Kokorev et al. 2024b; I. Labbe et al. 2024;
X. Lin et al. 2024; A. J. Taylor et al. 2025). The presence of such absorption implies
high gas densities of order n ∼ 109 cm−3 (P. B. Hall 2007; K. Inayoshi & R. Maiolino
2025). Interestingly, only atoms in the n = 2 state appear significantly populated,
as we detect no evidence for Paschen absorption in any of the five lines present
in our spectrum. This is not an instrumental effect of the M-grating, as we clearly
detect an absorption feature in He i λ10830 but not in the immediately adjacent
Paγ. This indicates that the n = 3 state is comparatively underpopulated.\r\n\r\nAnother
key manifestation of the same physical mechanism is the Balmer break, corresponding
to the n = ∞ → n = 2 transition limit. A prominent break is common in many LRD spectra
(D. J. Setton et al. 2025), though not ubiquitous (e.g., V. Kokorev et al. 2023;
R. Tripodi et al. 2025). While our spectral coverage does not extend to the Balmer
limit itself, we observe a discontinuity of ∼1 mag between the F200W and F150W filters.
Due to the F200W coverage of the SED, this flux jump cannot be attributed to line
boosting from Hβ and the [O iii] doublet. Adopting the break parameterization of
R. P. Naidu et al. (2025), we use our best-fit SED and measure fν,4050Å/fν,3670Å
= 2.02 ± 0.10. Although weaker than the extreme values (∼4–7) reported for LRDz9
(A. J. Taylor et al. 2025), MoM BH*-1 (R. P. Naidu et al. 2025), or “the Cliff”
(A. de Graaff et al. 2025b), this value lies close to the maximum achievable by
evolved stellar populations (I. Labbe et al. 2024; B. Wang et al. 2024). However,
this measurement is based on the total (PS+host) photometry. Given that the UV continuum
is spatially resolved, as we have shown in Section 4.1, host-galaxy contamination
may dilute the intrinsic break strength of the central component. While uncertainties
on the PS/host decomposition increase significantly toward the rest-optical, we
find that using the PS-only photometry produces a noticeably sharper break, increasing
the inferred strength by ∼30%–50% to fν,4050Å/fν,3670Å ≈ 2.6–3.0. Although this
does not allow us to robustly conclude whether the intrinsic PS break reaches the
most extreme BH*-type objects (A. de Graaff et al. 2025b; R. P. Naidu et al. 2025;
A. J. Taylor et al. 2025), it suggests that the Balmer discontinuity becomes stronger
once the host contribution is removed, consistent with recent findings that host
light can suppress the apparent break amplitude (e.g., A. de Graaff et al. 2025d;
W. Q. Sun et al. 2026).\r\n\r\nTaken together, the presence of asymmetry in the
Hα profile, likely caused by blueshifted Balmer absorption, and a Balmer break adds
to the evidence, complementing the exponential line wings, that the emission in
GLIMPSE-17775 arises from a dense, ionized cocoon of gas. The lack of a detectable
Paschen break is consistent with this picture, as high densities and optical depths
result in Thomson scattering while also naturally washing out higher-order continuum
edges (e.g., B. Wang et al. 2025). Assuming LTE, an extremely low ratio n3/n2 ≲
0.01 corresponds to an electron temperature of Te ∼ 5000 K or below, consistent
with the warm, partially ionized gas expected in dense LRD cocoons.\r\n\r\nWe also
observe moderately prominent and extremely prominent blueshifted absorption, respectively,
in He i λ7065 and He i λ10830. The mechanism for this is similar, but not identical
to, the hydrogen lines. We also note the prominent blueshifted absorption seen in
both He i λ7065 and He i λ10830. However, the physical mechanism driving these helium
features differs fundamentally from that of the hydrogen lines; we return to this
in the following section.\r\n\r\n5.5. Helium Lines\r\nBoth He i λ7065 and He i λ10830
show blueshifted (∼70−80 km s−1 from the narrow-line center) absorption components
with widths of ∼600−700 km s−1. Unlike the Balmer series, helium transitions are
resonantly scattered, so the arguments regarding n = 2 state abundances do not apply.
Before addressing the absorption itself, it is useful to consider what the observed
line strengths already tell us.\r\n\r\nIn the spectrum of GLIMPSE-17775, we detect
three He i lines: λ6680, λ7065, and λ10830. These originate from different physical
mechanisms. The λ6680 singlet line is produced via recombination or radiative pumping,
and is only weakly dependent on density. By contrast, λ7065 and λ10830 belong to
the triplet system (along with λ3889, not covered by G395M), where the lower level
is populated due to its very long lifetime. Electrons in this “ground state” can
be collisionally or radiatively excited into higher energies, and therefore the
triplet-line strengths depend strongly on density and, to a lesser extent, temperature.
As emphasized by D. A. Berg et al. (2026), He i λ10830 is the most sensitive density
diagnostic among these transitions, followed by λ7065. The fact that both are much
stronger than λ6680 indicates that the region where they form is very dense. The
prominence of λ10830 in particular already points to a high-density environment
with a temperature T ≳ 104 K. Further, the broad λ6680 line has a noticeably larger
FWHM than the triplet lines but is consistent with hydrogen recombination lines,
which again makes sense since both originate from the same mechanism.\r\n\r\nWhat
about absorption? Its presence further reinforces this picture. The lower level
(23S) of the triplet system is a metastable, long-lived state that effectively acts
as a ground state in dense or partially ionized gas. As a result, photons from the
23P → 23S transition can be resonantly absorbed and reemitted many times, analogous
to Lyα or Mg ii. This mechanism naturally produces strong absorption features when
the He i column density is high. The fact that He i λ10830 not only dominates the
helium spectrum in emission but also shows the deepest absorption in the entire
spectrum provides compelling evidence for a dense, ionized cocoon of gas enshrouding
GLIMPSE-17775.\r\n\r\n5.6. Oxygen Lines\r\nAbove, we noted that O i λ8446 and λ11290
share very similar profiles with the hydrogen recombination lines. This is naturally
expected because neutral oxygen is tightly coupled to hydrogen via charge exchange,
which rapidly equilibrates the O/H ionization states in dense gas. When charge exchange
is fast (high nH), the O i/O ii ratio tracks the H i/H ii ratio, so the O i-emitting
gas shares the same kinematics as the hydrogen recombination region (B. T. Draine
2011). The observed agreement in FWHM between H and O i lines is therefore an important
consistency check that both species originate in the same dense, partially ionized
phase.\r\n\r\nA second, independent clue of high gas density and radiation field
intensity comes from the excitation mechanism. The O iλ8446–λ11287 pair is the classic
signature of Lyβ (Bowen) fluorescence: Lyβ pumps O i from the ground state and the
ensuing cascade preferentially populates the levels that emit at 1.129 μm, which
then cascade down through the 8446 Å line. In this channel, the line emissivity
scales with both the neutral oxygen (or equivalently neutral hydrogen, via charge
exchange) column and the local Lyβ radiation field. Therefore, producing strong
O i fluorescence requires both a very bright Lyβ source and a dense neutral (or
partially ionized) cocoon.\r\n\r\nFurther, we do not detect (5σ upper limit <12/[10−20
erg s−1 cm−2]) any of the other permitted O iλ7774, λ7254, and λ7790 lines, and
the [O i] λ6302/O i λ8446 ratio is weak. If collisional excitation or pure recombination
dominated, these lines would be comparatively strong; their absence strongly favors
Bowen fluorescence as the primary driver of the observed O i emission.\r\n\r\nFinally,
the velocity structure adds a natural stratification: hydrogen recombination and
O i (fluorescent, charge-exchange coupled) share similar widths and profiles, while
He i lines are systematically narrower. Since He i triplet transitions emerge from
a metastable 23S level (with distinct, density-sensitive population pathways and
resonant transfer), they likely trace a kinematically distinct layer within the
same cocoon.\r\n\r\n5.7. Lyα Fluorescence in Iron Lines\r\nPermitted iron emission,
primarily Fe ii and Fe iii (e.g., I. Labbe et al. 2024; R. Tripodi et al. 2025;
A. Torralba et al. 2026), but in some cases extending to highly ionized species
such as Fe vii (E. Lambrides et al. 2025; M. Tang et al. 2025) and Fe x (L. J. Furtak
et al. 2024), has become a recurring feature in LRD spectra. In GLIMPSE-17775, the
spectrum is exceptionally rich in NIR iron lines; we identify 16 Fe ii and one Fe
iii transition. Understanding the origin of this emission is key to interpreting
the dense-gas environment in LRDs.\r\n\r\nThe physics of Fe ii emission has long
been a challenge for BLR photoionization models (M. Joly 1993). Thick, high-column-density
(∼1025 cm−2) gas at the edges of the accretion disk has been invoked as a potential
source (M. Joly 1987; S. Collin-Souffrin et al. 1988), where the scattering and
absorption of the hard X-ray photons ionize the gas. Similarly, this would also
enhance the Balmer and Paschen line luminosities. Further, extensive theoretical
work has shown that Lyα fluorescence is fundamental in reproducing the observed
Fe ii strengths (T. A. A. Sigut & A. K. Pradhan 1998, 2003). Lyα pumping not only
boosts the UV and optical Fe ii emission, but also predicts strong lines in the
NIR.\r\n\r\nThis expectation aligns closely with our observations. In Figure 8,
we compare our measured Fe ii flux ratios (normalized to Fe ii λ9075) against the
Lyα-pumped model predictions of T. A. A. Sigut & A. K. Pradhan (2003). With the
exception of Fe ii λ9179, affected by blending with Fe ii λ9204 and Pa9, we find
remarkably good agreement across the suite of detected features. In particular,
the dense forest of Fe ii transitions spanning λλ9000–9200 (center-right panel in
Figure 2) is reproduced almost exactly by the theoretical spectrum (see Figure 11
in T. A. A. Sigut & A. K. Pradhan 2003). We overlay the T. A. A. Sigut & A. K. Pradhan
(2003) model directly on our continuum-subtracted fit in Figure 8, demonstrating
that the observed Fe ii emission is fully consistent with fluorescence in dense
gas near the BLR. The implication is that the majority of the Fe ii emission in
GLIMPSE-17775 arises through Lyα pumping, directly tracing an extremely dense medium,
ionized by an extremely luminous source, likely an accreting black hole. Given that
the Fe ii lines are somewhat narrower than other permitted features, it is likely
that the emitting region is located farther from the BLR—something that has already
been shown in a classic example of a narrow Fe ii emitter, I Zw 1 (R. J. Rudy et
al. 2000; A. O. M. Marinello et al. 2016).\r\n\r\nZoom InZoom OutReset image size\r\nFigure
8. Lyα-pumped iron emission in GLIMPSE-17775. Left: observed Fe ii flux ratios (black
points), normalized to Fe iiλ9075, compared with predictions from Lyα fluorescence
models of T. A. A. Sigut & A. K. Pradhan (2003, blue). The close correspondence
across ∼14 lines indicates a common excitation mechanism driven by Lyα pumping in
dense, partially shielded gas. Right: zoom in on the λλ9000–9400 complex, showing
the remarkable agreement between the modeled continuum-subtracted Fe ii spectrum
(black) and the T. A. A. Sigut & A. K. Pradhan (2003) model (blue). We show air
wavelengths of each Fe ii line directly from T. A. A. Sigut & A. K. Pradhan (2003),
including the blended features. Together, these comparisons support an origin in
the dense inner regions of the cocoon surrounding the accreting black hole.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\nTogether with the Balmer absorption,
helium triplet features, and Bowen fluorescence in O i, the iron forest adds another
piece of evidence that points to a dense cocoon enshrouding the black hole.\r\n\r\n5.8.
Source Properties\r\nBased on the previous discussion, we now present the likely
physical properties of the black hole and its host. The coexistence of broad permitted
and narrow forbidden lines indicates, as in most LRDs (R. E. Hviding et al. 2025),
that the broad components originate in an AGN BLR. Following J. E. Greene & L. C.
Ho (2005), we derive MBH from the luminosity and width of the broad Hα line, assuming
the exponential-wing profile demonstrated in Figures 2 and 5. With a FWHMHα = 1024
± 21 km s−1, negligible dust, and μ = 2.04, we obtain , where the dominant uncertainty
arises from the J. E. Greene & L. C. Ho (2005) calibration. A purely Gaussian fit,
though statistically disfavored, would yield a FWHM 3 times larger and a black hole
mass nearly a dex higher. Throughout this work, we adopt the MBH from the exponential
model.\r\n\r\nFurther, by assuming that the bolometric luminosity (Lbol) scales
as Lbol = 130 × LHα (G. T. Richards et al. 2006), we find Lbol = (1.06 ± 0.14) ×
1045 erg s–1. Using our MBH derived by assuming exponential wings, we find that
this object is accreting at a super-Eddington rate, Lbol/Ledd = 1.86 ± 0.25. This
is higher than the vast majority of LRDs at all redshifts (e.g., V. Kokorev et al.
2023; L. J. Furtak et al. 2024; I. Juodžbalis et al. 2024; R. Maiolino et al. 2024;
H. B. Akins et al. 2025b; D. D. Kocevski et al. 2025; A. J. Taylor et al. 2025),
found to accrete at sub-Eddington rates. However, recent works examining LRDs with
extreme Balmer breaks derive accretion rates that exceed the Eddington limit (E.
Lambrides et al. 2024; A. de Graaff et al. 2025b; R. P. Naidu et al. 2025).\r\n\r\nA
recent work examining multiwavelength LRD data suggests that the bolometric luminosity
emerges predominantly from the rest-frame optical, with X-ray and radio contributions
being largely subdominant (J. E. Greene et al. 2026). Given the suggested dominance
of optical light in LRDs, the much lower bolometric corrections (×7–10 lower) would
imply lower black hole masses and total bolometric luminosities (e.g., those derived
from Hα) than standard AGN prescriptions (e.g., J. E. Greene & L. C. Ho 2005) might
suggest. This adjustment would lower both the inferred black hole masses and bolometric
luminosities. Because these two quantities scale together, the implied super-Eddington
nature of GLIMPSE-17775 would remain unchanged, although the black hole mass could
decrease to ∼105.5–105.8M⊙. This interpretation is consistent with dense-gas (BH*)
models, which generically predict Eddington or super-Eddington accretion in heavily
obscured environments (e.g., D. Kido et al. 2025; H. Liu et al. 2025; A. Sneppen
et al. 2026). A more detailed reassessment of bolometric corrections for LRDs is
clearly warranted, but such an analysis lies beyond the scope of this work. For
consistency with previous studies, we adopt standard AGN bolometric corrections
throughout, with all derived parameters listed in Table 1.\r\n\r\nFinally, we estimate
an upper limit on the stellar mass in GLIMPSE-17775. Previous studies have modeled
LRDs using joint galaxy+AGN SED decomposition (e.g., V. Kokorev et al. 2023; L.
J. Furtak et al. 2024), and more recently, within the BH* framework, have assumed
that most of the rest-UV flux arises from the host galaxy (R. P. Naidu et al. 2025;
A. J. Taylor et al. 2025). Our spatial decomposition (Figure 4) supports this assumption:
The extended component contributes >80% of the rest-UV light, implying that the
bulk of the stellar mass resides in this resolved structure. Given this, we adopt
a simple empirical approach using the MUV–M* relation (e.g., D. P. Stark et al.
2009; I. Labbé et al. 2013) and obtain a conservative upper limit on the stellar
mass of M* ≲ 107.5M⊙. This in turn gives us a black hole-to-host mass ratio of ≲0.14,
which is significantly elevated from local expectations (J. E. Greene & L. C. Ho
2005), but is not as extreme as some other LRDs reported in the literature (V. Kokorev
et al. 2023; L. J. Furtak et al. 2024; R. Maiolino et al. 2024).\r\n\r\n6. Discussion
and Summary\r\n6.1. Dense and Ionized Gas Surrounding the AGN\r\nOur NIRSpec G395M
observations of GLIMPSE-17775 reveal a remarkably consistent picture: Across independent
tracers, the line emission requires an environment of extremely high density and
partial ionization.\r\n\r\nFirst, the broad permitted lines are universally better
fit by exponential wings, a hallmark of electron scattering in gas with ne ≳ 108
cm−3 and column densities approaching Ne ∼ 1024 cm−2. Such profiles are not reproduced
by Doppler broadening alone and point to an ionized scattering medium enveloping
the source. The fact that hydrogen and O i lines share consistent FWHM values further
anchors this interpretation, as charge exchange tightly couples neutral oxygen to
the ionization and kinematics of hydrogen.\r\n\r\nSecond, the detection of blueshifted
Balmer absorption and a significant Balmer break both require high n = 2 populations
and densities n ∼ 109 cm−3. Helium transitions provide a complementary view: The
triplet lines λ7065 and λ10830 are both strongly enhanced relative to the singlet
states and show deep blueshifted absorption, consistent with resonant scattering
from the metastable 23S level. Their systematically narrower widths compared to
hydrogen and oxygen suggest stratification, with helium arising from denser, more
compact layers of the cocoon.\r\n\r\nThird, the O i λ8446–λ11290 pair confirms Lyβ
fluorescence, requiring both a bright Lyβ radiation field and a dense reservoir
of neutral gas. The absence of other permitted O i lines not fed by Lyβ strengthens
this conclusion. Finally, the detection of 16 Fe ii lines, forming an incredibly
rich iron forest in this LRD, matches predictions from Lyα fluorescence models,
again demanding an intense radiation field and very high densities.\r\n\r\nBecause
the BLR is unresolved in essentially all AGN, broad-line widths are traditionally
interpreted as virial tracers of the black hole potential. In GLIMPSE-17775, the
virial story alone is insufficient: The issue is not how broad the lines are, but
how they broaden. The profiles exhibit extended, nearly linear wings in velocity
space that are incompatible with a Gaussian. Instead, the lines are systematically
and significantly better described by a model consisting of a narrow Gaussian core
(virial motion) plus exponential wings, the hallmark of Thomson scattering in a
dense ionized medium. Thus, the line shape encodes both gravitational kinematics
and radiative-transfer physics in the surrounding cocoon. Our schematic (Figure
9) summarizes this revised view: In LRDs, broad-line profiles are not set by dynamics
alone, but by the scattering environment through which the photons escape.\r\n\r\nZoom
InZoom OutReset image size\r\nFigure 9. Physical picture of the dense cocoon around
GLIMPSE-17775. The inner region (1) corresponds to the dense, highly ionized broad-line
region (BLR) where electron scattering (orange lines) produces exponential wings,
H and O I share coupled kinematics (via charge exchange and Bowen fluorescence),
and strong Balmer absorption/break signatures arise. The outer layer (2) represents
an intermediate-density ionized medium, where He I triplet lines show resonant absorption
from the metastable 23S level and Fe II emission is driven by Lyα fluorescence.
Together, these zones form a stratified cocoon enshrouding the accreting black hole.
The bottom-right panel shows stacked line profiles of H, O i, He i, and Fe ii.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\nSuch conditions—high optical
depths, large column densities, and evidence for radiation-dominated gas—are precisely
those expected in super-Eddington accretion flows. In this regime, radiation pressure
inflates the inner accretion structure, driving powerful winds and forming the very
dense, partially ionized envelope we infer here. The low X-ray luminosities and
weak radio emission commonly observed in LRDs (e.g., T. T. Ananna et al. 2024; M.
Yue et al. 2024; H. B. Akins et al. 2025a; M. Kokubo & Y. Harikane 2025) are consistent
with this picture: The X-rays are likely absorbed or thermalized within the optically
thick cocoon, while dust cannot survive in such an intense radiation field (e.g.,
E. Lambrides et al. 2024; A. de Graaff et al. 2025b; K. Inayoshi & R. Maiolino 2025;
R. P. Naidu et al. 2025; A. J. Taylor et al. 2025). Thus, the spectroscopic signatures
observed in GLIMPSE-17775—exponential wings, absorption features, and fluorescence-driven
metal lines—fit naturally into a scenario where super-Eddington accretion onto a
low-mass black hole powers the luminous yet heavily reprocessed emission.\r\n\r\nTaken
together, the exponential wings, Balmer and helium absorption, Bowen oxygen lines,
and Lyα-pumped iron forest all converge on the same physical picture: GLIMPSE-17775
is enshrouded in a dense, partially ionized cocoon of gas.\r\n\r\n6.2. Final Remarks\r\nUsing
a combination of the intrinsically deepest NIRCam photometry and NIRSpec G395M observations
of the lensed AS1063 field, we present a detailed investigation of a LRD at z =
3.501. The spectrum of GLIMPSE-17775 is exceptionally rich, with more than 40 detected
features, allowing us to probe the physical conditions of the gas with unprecedented
detail. Multiple independent diagnostics converge on the presence of a dense, partially
ionized cocoon heated by a powerful ionizing source.\r\n\r\nTypical of other LRDs,
GLIMPSE-17775 is extremely compact in the rest-optical (reff < 300 pc) but exhibits
more extended structure in the rest-UV (reff ∼ 1000 pc; Figure 1). It shows unmistakable
AGN signatures through broad permitted lines (e.g., D. D. Kocevski et al. 2023;
V. Kokorev et al. 2023; J. E. Greene et al. 2024; L. J. Furtak et al. 2024). The
uniquely deep G395M spectrum further reveals clues to the physical origin of both
its continuum and line-emission properties: We detect exponential broad-line wings,
Balmer and helium absorption, Bowen-pumped O i, Fe ii emission produced by Lyα fluorescence,
and evidence for rapid, potentially super-Eddington growth.\r\n\r\nTogether, these
diagnostics provide one of the clearest cases yet for the BH* “dense cocoon” scenario
(A. de Graaff et al. 2025b; K. Inayoshi & R. Maiolino 2025; R. P. Naidu et al. 2025;
A. J. Taylor et al. 2025). The same ingredients we observe—exponential broad wings,
Balmer-break absorption, He i absorption, and rich Fe ii and O i fluorescence—have
been detected individually in several other bright LRDs with medium- and high-resolution
spectroscopy (e.g., L. J. Furtak et al. 2024; I. Juodžbalis et al. 2024; I. Labbe
et al. 2024; F. D’Eugenio et al. 2025; E. Lambrides et al. 2025; B. Wang et al.
2025; A. Torralba et al. 2026), suggesting that dense, optically thick gas may be
a common feature of the population rather than an anomaly. What distinguishes GLIMPSE-17775
is that all signatures are captured simultaneously and at high S/N, allowing a self-consistent
physical interpretation. If such cocoons are widespread, then super-Eddington accretion
may be a typical pathway for black hole growth in LRDs, especially among the most
luminous systems. Establishing how these signatures vary with luminosity and redshift
will be essential for determining whether dense cocoons represent a dominant mode
of early black hole assembly.\r\n\r\nThe convergence of five independent diagnostics—exponential
scattering wings, Balmer-limit absorption, helium triplet physics, and two distinct
fluorescence channels—leaves little doubt: GLIMPSE-17775 hosts a dense (n ∼ 108−9
cm−3), optically thick (Ne ∼ 1024 cm−2) cocoon of partially ionized gas surrounding
a super-Eddington accreting black hole. This represents some of the most direct
and comprehensive spectroscopic evidence to date for the dense cocoon scenario in
LRDs.\r\n\r\nAcknowledgments\r\nThe authors would like to thank Aaron Sigut and
Anil Pradhan for their help with understanding iron emission in active galactic
nuclei. The authors would like to acknowledge the National Institute of Standards
and Technology (NIST) database of spectral lines (A. Kramida et al. 2024), which
made identification of less-known emission features possible. V.K., J.C., S.F.,
D.B., L.F., T.H., and J.M. acknowledge support from the University of Texas at Austin
Cosmic Frontier Center. A.Z. acknowledges support by the Israel Science Foundation
grant No. 864/23. This work is based on observations made with the NASA/ESA/CSA
James Webb Space Telescope, obtained at the Space Telescope Science Institute, which
is operated by the Association of Universities for Research in Astronomy, Incorporated,
under NASA contract NAS5-03127. The JWST data presented in this article were obtained
from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science
Institute. The specific observations analyzed can be accessed via doi:10.17909/4byn-fe55
and doi:10.17909/zq0c-8t87. These observations are associated with programs GO #3293
and DDT #9223.\r\n\r\nFacilities: JWST - James Webb Space Telescope, HST - Hubble
Space Telescope satellite.\r\n\r\nSoftware: EAZY (G. B. Brammer et al. 2008), grizli
(G. Brammer 2023), msaexp (G. Brammer 2022), photutils (L. Bradley et al. 2020),
pysersic (I. Pasha & T. B. Miller 2023), sep (K. Barbary 2016), SExtractor (E. Bertin
& S. Arnouts1996)."
article_number: '153'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Vasily
full_name: Kokorev, Vasily
last_name: Kokorev
- first_name: John
full_name: Chisholm, John
last_name: Chisholm
- first_name: Rohan P.
full_name: Naidu, Rohan P.
last_name: Naidu
- first_name: Seiji
full_name: Fujimoto, Seiji
last_name: Fujimoto
- first_name: Hakim
full_name: Atek, Hakim
last_name: Atek
- first_name: Gabriel
full_name: Brammer, Gabriel
last_name: Brammer
- first_name: Steven L.
full_name: Finkelstein, Steven L.
last_name: Finkelstein
- first_name: Hollis B.
full_name: Akins, Hollis B.
last_name: Akins
- first_name: Danielle A.
full_name: Berg, Danielle A.
last_name: Berg
- first_name: Lukas J.
full_name: Furtak, Lukas J.
last_name: Furtak
- first_name: Qinyue
full_name: Fei, Qinyue
last_name: Fei
- first_name: Tiger Yu-Yang
full_name: Hsiao, Tiger Yu-Yang
last_name: Hsiao
- first_name: Ivo
full_name: Labbé, Ivo
last_name: Labbé
- first_name: Jorryt J
full_name: Matthee, Jorryt J
id: 7439a258-f3c0-11ec-9501-9df22fe06720
last_name: Matthee
orcid: 0000-0003-2871-127X
- first_name: Julian B.
full_name: Muñoz, Julian B.
last_name: Muñoz
- first_name: Pascal A.
full_name: Oesch, Pascal A.
last_name: Oesch
- first_name: Richard
full_name: Pan, Richard
last_name: Pan
- first_name: Pierluigi
full_name: Rinaldi, Pierluigi
last_name: Rinaldi
- first_name: Alberto
full_name: Saldana-Lopez, Alberto
last_name: Saldana-Lopez
- first_name: Daniel
full_name: Schaerer, Daniel
last_name: Schaerer
- first_name: Marta
full_name: Volonteri, Marta
last_name: Volonteri
- first_name: Adi
full_name: Zitrin, Adi
last_name: Zitrin
citation:
ama: Kokorev V, Chisholm J, Naidu RP, et al. The Deepest GLIMPSE of a dense gas
cocoon enshrouding a Little Red Dot. The Astrophysical Journal. 2026;1004(2).
doi:10.3847/1538-4357/ae4ed7
apa: Kokorev, V., Chisholm, J., Naidu, R. P., Fujimoto, S., Atek, H., Brammer, G.,
… Zitrin, A. (2026). The Deepest GLIMPSE of a dense gas cocoon enshrouding a Little
Red Dot. The Astrophysical Journal. IOP Publishing. https://doi.org/10.3847/1538-4357/ae4ed7
chicago: Kokorev, Vasily, John Chisholm, Rohan P. Naidu, Seiji Fujimoto, Hakim Atek,
Gabriel Brammer, Steven L. Finkelstein, et al. “The Deepest GLIMPSE of a Dense
Gas Cocoon Enshrouding a Little Red Dot.” The Astrophysical Journal. IOP
Publishing, 2026. https://doi.org/10.3847/1538-4357/ae4ed7.
ieee: V. Kokorev et al., “The Deepest GLIMPSE of a dense gas cocoon enshrouding
a Little Red Dot,” The Astrophysical Journal, vol. 1004, no. 2. IOP Publishing,
2026.
ista: Kokorev V, Chisholm J, Naidu RP, Fujimoto S, Atek H, Brammer G, Finkelstein
SL, Akins HB, Berg DA, Furtak LJ, Fei Q, Hsiao TY-Y, Labbé I, Matthee JJ, Muñoz
JB, Oesch PA, Pan R, Rinaldi P, Saldana-Lopez A, Schaerer D, Volonteri M, Zitrin
A. 2026. The Deepest GLIMPSE of a dense gas cocoon enshrouding a Little Red Dot.
The Astrophysical Journal. 1004(2), 153.
mla: Kokorev, Vasily, et al. “The Deepest GLIMPSE of a Dense Gas Cocoon Enshrouding
a Little Red Dot.” The Astrophysical Journal, vol. 1004, no. 2, 153, IOP
Publishing, 2026, doi:10.3847/1538-4357/ae4ed7.
short: V. Kokorev, J. Chisholm, R.P. Naidu, S. Fujimoto, H. Atek, G. Brammer, S.L.
Finkelstein, H.B. Akins, D.A. Berg, L.J. Furtak, Q. Fei, T.Y.-Y. Hsiao, I. Labbé,
J.J. Matthee, J.B. Muñoz, P.A. Oesch, R. Pan, P. Rinaldi, A. Saldana-Lopez, D.
Schaerer, M. Volonteri, A. Zitrin, The Astrophysical Journal 1004 (2026).
das_tickbox: '1'
dataavailabilitystatement: "The specific observations analyzed can be accessed via
doi:10.17909/4byn-fe55 and doi:10.17909/zq0c-8t87. These observations are associated
with programs GO #3293 and DDT #9223.\r\n\r\nFacilities: JWST - James Webb Space
Telescope, HST - Hubble Space Telescope satellite.\r\n\r\nSoftware: EAZY (G. B.
Brammer et al. 2008), grizli (G. Brammer 2023), msaexp (G. Brammer 2022), photutils
(L. Bradley et al. 2020), pysersic (I. Pasha & T. B. Miller 2023), sep (K. Barbary
2016), SExtractor (E. Bertin & S. Arnouts1996)."
date_created: 2026-07-13T09:48:38Z
date_published: 2026-06-10T00:00:00Z
date_updated: 2026-07-13T13:25:09Z
day: '10'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.3847/1538-4357/ae4ed7
external_id:
arxiv:
- '2511.07515'
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intvolume: ' 1004'
issue: '2'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
publication: The Astrophysical Journal
publication_identifier:
eissn:
- 1538-4357
issn:
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publication_status: published
publisher: IOP Publishing
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supplementarymaterial: no
title: The Deepest GLIMPSE of a dense gas cocoon enshrouding a Little Red Dot
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legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
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