---
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '21045'
abstract:
- lang: eng
  text: 'The abundant population of little red dots (LRDs), compact objects with red
    UV to optical colors and broad Balmer lines at high redshift, is revealing new
    insights into the properties of early active galactic nuclei (AGN). Perhaps the
    most surprising features of this population are the presence of Balmer absorption
    and ubiquitous strong Balmer breaks. Recent models link these features to an active
    supermassive black hole (SMBH) cocooned in very dense gas (NH ∼ 1024 cm−2). We
    present a stringent test of such models using VLT/MUSE observations of A2744-45924,
    the most luminous LRD known to date (LHα ≈ 1044 erg s−1), located behind the Abell-2744
    lensing cluster at z = 4.464 (μ = 1.8). We detect a moderately extended Lyα nebula
    (h ≈ 5.7 pkpc), spatially offset from the point-like Hα seen by JWST by ≈1.6 pkpc.
    The Lyα emission is narrow (FWHM = 270 ± 15 km s−1), and faint (Lyα = 0.07Hα)
    compared to Lyα nebulae typically observed around quasars of similar luminosity.
    We detect compact N IV]λ1486 emission, spatially aligned with Hα, and a spatial
    shift in the far-UV continuum matching the Lyα offset. We discuss that Hα and
    Lyα have distinct physical origins: Hα originates from the AGN, while Lyα is powered
    by star formation. In the environment of A2744-45924, we identified four extended
    Lyα halos (Δz < 0.02, Δr < 100 pkpc). Their Lyα luminosities match the expectations
    based on Hα emission, and show no evidence for radiation from A2744-45924 affecting
    its surroundings. The lack of strong, compact, and broad Lyα and the absence of
    a luminous extended halo, suggest that the UV AGN light is obscured by dense gas
    cloaking the SMBH with a covering factor close to unity.'
acknowledgement: 'We thank the anonymous referee for constructive and useful comments.
  We thank Sebastiano Cantalupo for comments on the draft. Based on observations collected
  at the European Organisation for Astronomical Research in the Southern Hemisphere
  under ESO programme 114.27M6.001. Funded by the European Union (ERC, AGENTS, 101076224).
  Views and opinions expressed are however those of the author(s) 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. We acknowledge funding from JWST program GO-3516. This 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 program #3516. MG thanks the Max Planck Society for support
  through the MPRG. FDE acknowledges support by the Science and Technology Facilities
  Council (STFC), by the ERC through Advanced Grant 695671 “QUENCH”, and by the UKRI
  Frontier Research grant RISEandFALL. TU acknowledges funding from the ERC-AdG grant
  SPECMAP-CGM, GA 101020943. GK acknowledges support from the MERAC foundation.'
article_number: A147
article_processing_charge: No
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: Gabriele
  full_name: Pezzulli, Gabriele
  last_name: Pezzulli
- first_name: Tanya
  full_name: Urrutia, Tanya
  last_name: Urrutia
- first_name: Max
  full_name: Gronke, Max
  last_name: Gronke
- first_name: Sara
  full_name: Mascia, Sara
  id: edaf889c-c7cd-11ef-ab1b-bb28c431bd29
  last_name: Mascia
- first_name: Francesco
  full_name: D’Eugenio, Francesco
  last_name: D’Eugenio
- first_name: Claudia
  full_name: Di Cesare, Claudia
  id: 2d002343-372f-11ef-98ec-a164d20427cb
  last_name: Di Cesare
- first_name: Anna Christina
  full_name: Eilers, Anna Christina
  last_name: Eilers
- first_name: Jenny E.
  full_name: Greene, Jenny E.
  last_name: Greene
- first_name: Edoardo
  full_name: Iani, Edoardo
  id: 4053390a-6b68-11ef-9828-a3b8adef8d0a
  last_name: Iani
  orcid: 0000-0001-8386-3546
- first_name: Yuzo
  full_name: Ishikawa, Yuzo
  last_name: Ishikawa
- first_name: Ruari
  full_name: Mackenzie, Ruari
  last_name: Mackenzie
- first_name: Rohan P.
  full_name: Naidu, Rohan P.
  last_name: Naidu
- first_name: Benjamín
  full_name: Navarrete, Benjamín
  id: aa14a535-50c9-11ef-b52e-e0c373d10148
  last_name: Navarrete
- first_name: Gauri
  full_name: Kotiwale, Gauri
  id: 1438afc8-1ff6-11ee-9fa6-cd4a75d66875
  last_name: Kotiwale
citation:
  ama: Torralba Torregrosa A, Matthee JJ, Pezzulli G, et al. A weak Ly α halo for
    an extremely bright little red dot. Indications of enshrouded supermassive black
    hole growth. <i>Astronomy and Astrophysics</i>. 2026;705. doi:<a href="https://doi.org/10.1051/0004-6361/202555596">10.1051/0004-6361/202555596</a>
  apa: Torralba Torregrosa, A., Matthee, J. J., Pezzulli, G., Urrutia, T., Gronke,
    M., Mascia, S., … Kotiwale, G. (2026). A weak Ly α halo for an extremely bright
    little red dot. Indications of enshrouded supermassive black hole growth. <i>Astronomy
    and Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202555596">https://doi.org/10.1051/0004-6361/202555596</a>
  chicago: Torralba Torregrosa, Alberto, Jorryt J Matthee, Gabriele Pezzulli, Tanya
    Urrutia, Max Gronke, Sara Mascia, Francesco D’Eugenio, et al. “A Weak Ly α Halo
    for an Extremely Bright Little Red Dot. Indications of Enshrouded Supermassive
    Black Hole Growth.” <i>Astronomy and Astrophysics</i>. EDP Sciences, 2026. <a
    href="https://doi.org/10.1051/0004-6361/202555596">https://doi.org/10.1051/0004-6361/202555596</a>.
  ieee: A. Torralba Torregrosa <i>et al.</i>, “A weak Ly α halo for an extremely bright
    little red dot. Indications of enshrouded supermassive black hole growth,” <i>Astronomy
    and Astrophysics</i>, vol. 705. EDP Sciences, 2026.
  ista: Torralba Torregrosa A, Matthee JJ, Pezzulli G, Urrutia T, Gronke M, Mascia
    S, D’Eugenio F, Di Cesare C, Eilers AC, Greene JE, Iani E, Ishikawa Y, Mackenzie
    R, Naidu RP, Navarrete B, Kotiwale G. 2026. A weak Ly α halo for an extremely
    bright little red dot. Indications of enshrouded supermassive black hole growth.
    Astronomy and Astrophysics. 705, A147.
  mla: Torralba Torregrosa, Alberto, et al. “A Weak Ly α Halo for an Extremely Bright
    Little Red Dot. Indications of Enshrouded Supermassive Black Hole Growth.” <i>Astronomy
    and Astrophysics</i>, vol. 705, A147, EDP Sciences, 2026, doi:<a href="https://doi.org/10.1051/0004-6361/202555596">10.1051/0004-6361/202555596</a>.
  short: A. Torralba Torregrosa, J.J. Matthee, G. Pezzulli, T. Urrutia, M. Gronke,
    S. Mascia, F. D’Eugenio, C. Di Cesare, A.C. Eilers, J.E. Greene, E. Iani, Y. Ishikawa,
    R. Mackenzie, R.P. Naidu, B. Navarrete, G. Kotiwale, Astronomy and Astrophysics
    705 (2026).
corr_author: '1'
date_created: 2026-01-25T23:01:41Z
date_published: 2026-01-14T00:00:00Z
date_updated: 2026-02-16T07:46:53Z
day: '14'
ddc:
- '520'
department:
- _id: JoMa
- _id: GradSch
doi: 10.1051/0004-6361/202555596
external_id:
  arxiv:
  - '2505.09542'
file:
- access_level: open_access
  checksum: 3782e03bc0843438aae8487f6af779c5
  content_type: application/pdf
  creator: dernst
  date_created: 2026-02-16T07:35:03Z
  date_updated: 2026-02-16T07:35:03Z
  file_id: '21224'
  file_name: 2026_AstronomyAstrophysics_Torralba.pdf
  file_size: 2259914
  relation: main_file
  success: 1
file_date_updated: 2026-02-16T07:35:03Z
has_accepted_license: '1'
intvolume: '       705'
language:
- iso: eng
month: '01'
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: Astronomy and Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: A weak Ly α halo for an extremely bright little red dot. Indications of enshrouded
  supermassive black hole growth
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: 705
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '21341'
abstract:
- lang: eng
  text: We aim to characterise the mass-metallicity relation (MZR) and the 3D correlation
    between the stellar mass, metallicity, and star formation rate (SFR) known as
    the fundamental metallicity relation (FMR) for galaxies at 5 < z < 7. Using ∼800
    [O III] selected galaxies from deep NIRCam grism surveys, we present our stacked
    measurements of direct-Te metallicities, which we used to test recent strong-line
    metallicity calibrations. Our measured direct-Te metallicities (0.1–0.2 Z⊙ for
    M★ ≈ 5 × 107 − 9 M⊙, respectively) match recent JWST/NIRSpec-based results. However,
    there are significant inconsistencies between observations and hydrodynamical
    simulations. We observe a flatter MZR slope than the SPHINX20 and FLARES simulations,
    which cannot be attributed to selection effects. With simple models, we show that
    the effect of an [O III] flux-limited sample on the observed shape of the MZR
    is strongly dependent on the FMR. If the FMR is similar to the one in the local
    Universe, the intrinsic high-redshift MZR should be even flatter than is observed.
    In turn, a 3D relation where SFR correlates positively with metallicity at fixed
    mass would imply an intrinsically steeper MZR. Our measurements indicate that
    metallicity variations at fixed mass show little dependence on the SFR, suggesting
    a flat intrinsic MZR. This could indicate that the low-mass galaxies at these
    redshifts are out of equilibrium and that metal enrichment occurs rapidly in low-mass
    galaxies. However, being limited by our stacking analysis, we are yet to probe
    the scatter in the MZR and its dependence on SFR. Large carefully selected samples
    of galaxies with robust metallicity measurements can put tight constraints on
    the high-redshift FMR and help us to understand the interplay between gas flows,
    star formation, and feedback in early galaxies.
acknowledgement: 'We thank the anonymous referee for the insightful comments that
  helped improving this paper. 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 Associations of Universities for Research in Astronomy, Inc., under NASA contract
  NAS 5-03127 for JWST. These observations were taken under programmes # 1243, # 1933
  and # 3516. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions
  expressed are however those of the author(s) 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. GK acknowledges
  support from the Foundation MERAC. APV acknowledge support from the Sussex Astronomy
  Centre STFC Consolidated Grant (ST/X001040/1).'
article_number: A165
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Gauri
  full_name: Kotiwale, Gauri
  id: 1438afc8-1ff6-11ee-9fa6-cd4a75d66875
  last_name: Kotiwale
- 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: Daichi
  full_name: Kashino, Daichi
  last_name: Kashino
- first_name: Aswin P.
  full_name: Vijayan, Aswin P.
  last_name: Vijayan
- 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: Claudia
  full_name: Di Cesare, Claudia
  id: 2d002343-372f-11ef-98ec-a164d20427cb
  last_name: Di Cesare
- first_name: Edoardo
  full_name: Iani, Edoardo
  id: 4053390a-6b68-11ef-9828-a3b8adef8d0a
  last_name: Iani
  orcid: 0000-0001-8386-3546
- first_name: Rongmon
  full_name: Bordoloi, Rongmon
  last_name: Bordoloi
- first_name: Joel
  full_name: Leja, Joel
  last_name: Leja
- first_name: Michael V.
  full_name: Maseda, Michael V.
  last_name: Maseda
- first_name: Sandro
  full_name: Tacchella, Sandro
  last_name: Tacchella
- first_name: Irene
  full_name: Shivaei, Irene
  last_name: Shivaei
- first_name: Kasper E.
  full_name: Heintz, Kasper E.
  last_name: Heintz
- first_name: A. Lola
  full_name: Danhaive, A. Lola
  last_name: Danhaive
- first_name: Sara
  full_name: Mascia, Sara
  id: edaf889c-c7cd-11ef-ab1b-bb28c431bd29
  last_name: Mascia
- first_name: Ivan
  full_name: Kramarenko, Ivan
  id: 9a9394cb-3200-11ee-973b-f5ba2a8b16e4
  last_name: Kramarenko
  orcid: 0000-0001-5346-6048
- first_name: Benjamín
  full_name: Navarrete, Benjamín
  id: aa14a535-50c9-11ef-b52e-e0c373d10148
  last_name: Navarrete
- first_name: Ruari
  full_name: Mackenzie, Ruari
  last_name: Mackenzie
- first_name: Rohan P.
  full_name: Naidu, Rohan P.
  last_name: Naidu
- first_name: David
  full_name: Sobral, David
  last_name: Sobral
citation:
  ama: Kotiwale G, Matthee JJ, Kashino D, et al. Rapid, out-of-equilibrium metal enrichment
    indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy.
    <i>Astronomy &#38; Astrophysics</i>. 2026;706. doi:<a href="https://doi.org/10.1051/0004-6361/202556597">10.1051/0004-6361/202556597</a>
  apa: Kotiwale, G., Matthee, J. J., Kashino, D., Vijayan, A. P., Torralba Torregrosa,
    A., Di Cesare, C., … Sobral, D. (2026). Rapid, out-of-equilibrium metal enrichment
    indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy.
    <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202556597">https://doi.org/10.1051/0004-6361/202556597</a>
  chicago: Kotiwale, Gauri, Jorryt J Matthee, Daichi Kashino, Aswin P. Vijayan, Alberto
    Torralba Torregrosa, Claudia Di Cesare, Edoardo Iani, et al. “Rapid, out-of-Equilibrium
    Metal Enrichment Indicated by a Flat Mass-Metallicity Relation at z ∼ 6 from NIRCam
    Grism Spectroscopy.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026.
    <a href="https://doi.org/10.1051/0004-6361/202556597">https://doi.org/10.1051/0004-6361/202556597</a>.
  ieee: G. Kotiwale <i>et al.</i>, “Rapid, out-of-equilibrium metal enrichment indicated
    by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy,”
    <i>Astronomy &#38; Astrophysics</i>, vol. 706. EDP Sciences, 2026.
  ista: Kotiwale G, Matthee JJ, Kashino D, Vijayan AP, Torralba Torregrosa A, Di Cesare
    C, Iani E, Bordoloi R, Leja J, Maseda MV, Tacchella S, Shivaei I, Heintz KE, Danhaive
    AL, Mascia S, Kramarenko I, Navarrete B, Mackenzie R, Naidu RP, Sobral D. 2026.
    Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity
    relation at z ∼ 6 from NIRCam grism spectroscopy. Astronomy &#38; Astrophysics.
    706, A165.
  mla: Kotiwale, Gauri, et al. “Rapid, out-of-Equilibrium Metal Enrichment Indicated
    by a Flat Mass-Metallicity Relation at z ∼ 6 from NIRCam Grism Spectroscopy.”
    <i>Astronomy &#38; Astrophysics</i>, vol. 706, A165, EDP Sciences, 2026, doi:<a
    href="https://doi.org/10.1051/0004-6361/202556597">10.1051/0004-6361/202556597</a>.
  short: G. Kotiwale, J.J. Matthee, D. Kashino, A.P. Vijayan, A. Torralba Torregrosa,
    C. Di Cesare, E. Iani, R. Bordoloi, J. Leja, M.V. Maseda, S. Tacchella, I. Shivaei,
    K.E. Heintz, A.L. Danhaive, S. Mascia, I. Kramarenko, B. Navarrete, R. Mackenzie,
    R.P. Naidu, D. Sobral, Astronomy &#38; Astrophysics 706 (2026).
corr_author: '1'
date_created: 2026-02-22T23:01:35Z
date_published: 2026-02-01T00:00:00Z
date_updated: 2026-02-24T07:49:42Z
day: '01'
ddc:
- '520'
department:
- _id: JoMa
- _id: GradSch
doi: 10.1051/0004-6361/202556597
external_id:
  arxiv:
  - '2510.19959'
file:
- access_level: open_access
  checksum: 6f5849d29ad43bee32f90152f6fc0294
  content_type: application/pdf
  creator: dernst
  date_created: 2026-02-24T07:46:47Z
  date_updated: 2026-02-24T07:46:47Z
  file_id: '21355'
  file_name: 2026_AstronomyAstrophysics_Kotiwale.pdf
  file_size: 6531719
  relation: main_file
  success: 1
file_date_updated: 2026-02-24T07:46:47Z
has_accepted_license: '1'
intvolume: '       706'
language:
- iso: eng
month: '02'
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: 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: Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity
  relation at z ∼ 6 from NIRCam grism spectroscopy
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: 706
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
_id: '21380'
abstract:
- lang: eng
  text: "Context. Extreme emission line galaxies (EELGs) are believed to significantly
    contribute to the star formation activity and mass assembly in galaxies. EELGs
    likely also play a leading role in the cosmic re-ionization as their interstellar
    medium may allow a significant fraction of their ionizing photons to escape (>
    5%). Finding low-redshift analogues of these high-z galaxies is therefore essential
    to characterizing the physical conditions in the interstellar medium of these
    galaxies and understanding the processes that re-ionized the Universe.\r\n\r\nAims.
    We aimed to develop a robust and efficient method for the photometric identification
    of EELGs using the J-PAS survey. J-PAS will cover approximately 8500 deg2 of the
    sky with 54 narrow-band filters in the optical range plus i-SDSS, enabling detailed
    studies of the physical properties of these galaxies. In this work we focused
    on an initial subset of the survey: a 30 square degree area with complete observations
    in all bands.\r\n\r\nMethods. We combine equivalent width (EW) measurements from
    J-PAS narrow-band photometry with artificial intelligence techniques to identify
    galaxies with emission lines exceeding 300 Å. We validated our selection using
    spectroscopic data from DESI DR1 and characterized the selected sample through
    spectral energy distribution fitting with CIGALE.\r\n\r\nResults. We identify
    917 EELGs up to z = 0.8 over 30 deg2, achieving a purity of 95% and a completeness
    of 96% for i-SDSS < 22.5 mag. Importantly, active galactic nucleus contamination
    was carefully considered and is estimated to be around 5%. Furthermore, a cross-match
    with DESI yielded 79 counterparts; their redshifts are in excellent agreement
    with our photometric estimates, thereby confirming the reliability of our redshift
    determination. In addition, the derived emission line fluxes are in good agreement
    with spectroscopic measurements. Moreover, the selected sample reveals strong
    correlations between the ionizing photon production efficiency (ξion) and EW(Hβ),
    which are consistent with previous observational studies at low and high redshifts
    and theoretical expectations. Finally, most of the sources surpass the ionizing
    efficiency threshold required for re-ionization, highlighting their relevance
    as local analogues of early-Universe galaxies."
acknowledgement: "We thank the referee for several helpful suggestions. AGA, MGO and
  IM acknowledge financial support from the Severo Ochoa grant CEX2021-001131-S, funded
  by MICIU/AEI/10.13039/501100011033. AGA also acknowledges FPI support under grant
  code CEX2021-001131-S20-7. Both AGA and MGO acknowledge support from the research
  grant\r\nPID2022-136598NB-C32 (“Estallidos8”). MGO also acknowledges the support
  by the project ref. AST22_00001_Subp_11 funded from the EU – NextGenerationEU. RA
  acknowledges support from PID2023-147386NB-I00 funded by MICIU/AEI/10.13039/501100011033
  and ERDF/EU. IM acknowledges support from PID2022-140871NB-C21 funded by MICIU/AEI/10.13039/501100011033
  and FEDER/UE. RGD acknowledge financial support from the project PID2022-141755NB-I00,
  and the Severo Ochoa grant CEX2021-001131-S funded\r\nby MICIU/AEI/ 10.13039/501100011033.
  JAFO and AE acknowledge support from the Spanish Ministry of Science and Innovation
  and the EU–NextGenerationEU through the RRF project ICTS-MRR-2021-03-CEFCA. AHC
  and ALC acknowledge support from MCIN/AEI/10.13039/501100011033, “ERDF A way of
  making Europe”, and “EU NextGenerationEU/PRTR” through PID2021-124918NB-C44 and
  CNS2023-145339, as well as from the RRF project ICTS-MRR-2021-03-CEFCA ALC and RPT
  acknowledge the financial\r\nsupport from the European Union – NextGenerationEU
  through the RRF program Planes Complementarios con las CCAA de Astrofísica y Física
  de Altas Energías – LA4. I.B. acknowledges support from the EU Horizon 2020 programme
  (Marie Sklodowska-Curie Grant 101059532) and the Franziska Seidl Funding Program,
  University of Vienna. This paper has gone through internal‘ review by the J-PAS
  collaboration. Based on observations made with the\r\nJST/T250 telescope and JPCam
  at the Observatorio Astrofísico de Javalambre (OAJ), in Teruel, owned, managed,
  and operated by the Centro de Estudios de Física del Cosmos de Aragón (CEFCA). We
  acknowledge the OAJ Data Processing and Archiving Unit (UPAD) for reducing and calibrating
  the OAJ data used in this work. Funding for the J-PAS Project has been provided
  by the Governments of Spain and Aragón through the Fondo de Inversiones de Teruel;
  the Aragonese Government through the Research Groups E96, E103, E16_17R, E16_20R,
  and E16_23R; the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033
  y FEDER, Una manera de hacer Europa) with grants PID2021-124918NB-C41, PID2021-124918NB-C42,
  PID2021-124918NA-C43, and PID2021-124918NB-C44; the Spanish Ministry\r\nof Science,
  Innovation and Universities (MCIU/AEI/FEDER, UE) with grants\r\nPGC2018-097585-B-C21
  and PGC2018-097585-B-C22; the Spanish Ministry of Economy and Competitiveness (MINECO)
  under AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, and AYA2012-30789; and European
  FEDER funding (FCDD10-4E-867, FCDD13-4E-2685)."
article_number: A261
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: A.
  full_name: Giménez-Alcázar, A.
  last_name: Giménez-Alcázar
- first_name: R.
  full_name: Amorín, R.
  last_name: Amorín
- first_name: J. M.
  full_name: Vílchez, J. M.
  last_name: Vílchez
- first_name: A.
  full_name: Hernán-Caballero, A.
  last_name: Hernán-Caballero
- first_name: M.
  full_name: González-Otero, M.
  last_name: González-Otero
- first_name: A.
  full_name: Arroyo-Polonio, A.
  last_name: Arroyo-Polonio
- first_name: J.
  full_name: Iglesias-Páramo, J.
  last_name: Iglesias-Páramo
- first_name: A.
  full_name: Lumbreras-Calle, A.
  last_name: Lumbreras-Calle
- first_name: J. A.
  full_name: Fernández-Ontiveros, J. A.
  last_name: Fernández-Ontiveros
- first_name: C.
  full_name: López-Sanjuan, C.
  last_name: López-Sanjuan
- first_name: L.
  full_name: Bonatto, L.
  last_name: Bonatto
- first_name: R. M.
  full_name: González Delgado, R. M.
  last_name: González Delgado
- first_name: C.
  full_name: Kehrig, C.
  last_name: Kehrig
- 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: P. T.
  full_name: Rahna, P. T.
  last_name: Rahna
- first_name: Y.
  full_name: Jiménez-Teja, Y.
  last_name: Jiménez-Teja
- first_name: I.
  full_name: Márquez, I.
  last_name: Márquez
- first_name: I.
  full_name: Breda, I.
  last_name: Breda
- first_name: A.
  full_name: Álvarez-Candal, A.
  last_name: Álvarez-Candal
- first_name: R.
  full_name: Abramo, R.
  last_name: Abramo
- first_name: J.
  full_name: Alcaniz, J.
  last_name: Alcaniz
- first_name: N.
  full_name: Benitez, N.
  last_name: Benitez
- first_name: S.
  full_name: Bonoli, S.
  last_name: Bonoli
- first_name: S.
  full_name: Carneiro, S.
  last_name: Carneiro
- first_name: J.
  full_name: Cenarro, J.
  last_name: Cenarro
- first_name: D.
  full_name: Cristóbal-Hornillos, D.
  last_name: Cristóbal-Hornillos
- first_name: R.
  full_name: Dupke, R.
  last_name: Dupke
- first_name: A.
  full_name: Ederoclite, A.
  last_name: Ederoclite
- first_name: C.
  full_name: Hernández-Monteagudo, C.
  last_name: Hernández-Monteagudo
- first_name: A.
  full_name: Marín-Franch, A.
  last_name: Marín-Franch
- first_name: C.
  full_name: Mendes de Oliveira, C.
  last_name: Mendes de Oliveira
- first_name: M.
  full_name: Moles, M.
  last_name: Moles
- first_name: L.
  full_name: Sodré, L.
  last_name: Sodré
- first_name: K.
  full_name: Taylor, K.
  last_name: Taylor
- first_name: J.
  full_name: Varela, J.
  last_name: Varela
- first_name: H.
  full_name: Vázquez Ramió, H.
  last_name: Vázquez Ramió
citation:
  ama: 'Giménez-Alcázar A, Amorín R, Vílchez JM, et al. J-PAS: First identification,
    physical properties, and ionization efficiency of extreme emission line galaxies.
    <i>Astronomy &#38; Astrophysics</i>. 2026;706. doi:<a href="https://doi.org/10.1051/0004-6361/202557358">10.1051/0004-6361/202557358</a>'
  apa: 'Giménez-Alcázar, A., Amorín, R., Vílchez, J. M., Hernán-Caballero, A., González-Otero,
    M., Arroyo-Polonio, A., … Vázquez Ramió, H. (2026). J-PAS: First identification,
    physical properties, and ionization efficiency of extreme emission line galaxies.
    <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202557358">https://doi.org/10.1051/0004-6361/202557358</a>'
  chicago: 'Giménez-Alcázar, A., R. Amorín, J. M. Vílchez, A. Hernán-Caballero, M.
    González-Otero, A. Arroyo-Polonio, J. Iglesias-Páramo, et al. “J-PAS: First Identification,
    Physical Properties, and Ionization Efficiency of Extreme Emission Line Galaxies.”
    <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026. <a href="https://doi.org/10.1051/0004-6361/202557358">https://doi.org/10.1051/0004-6361/202557358</a>.'
  ieee: 'A. Giménez-Alcázar <i>et al.</i>, “J-PAS: First identification, physical
    properties, and ionization efficiency of extreme emission line galaxies,” <i>Astronomy
    &#38; Astrophysics</i>, vol. 706. EDP Sciences, 2026.'
  ista: 'Giménez-Alcázar A, Amorín R, Vílchez JM, Hernán-Caballero A, González-Otero
    M, Arroyo-Polonio A, Iglesias-Páramo J, Lumbreras-Calle A, Fernández-Ontiveros
    JA, López-Sanjuan C, Bonatto L, González Delgado RM, Kehrig C, Torralba Torregrosa
    A, Rahna PT, Jiménez-Teja Y, Márquez I, Breda I, Álvarez-Candal A, Abramo R, Alcaniz
    J, Benitez N, Bonoli S, Carneiro S, Cenarro J, Cristóbal-Hornillos D, Dupke R,
    Ederoclite A, Hernández-Monteagudo C, Marín-Franch A, Mendes de Oliveira C, Moles
    M, Sodré L, Taylor K, Varela J, Vázquez Ramió H. 2026. J-PAS: First identification,
    physical properties, and ionization efficiency of extreme emission line galaxies.
    Astronomy &#38; Astrophysics. 706, A261.'
  mla: 'Giménez-Alcázar, A., et al. “J-PAS: First Identification, Physical Properties,
    and Ionization Efficiency of Extreme Emission Line Galaxies.” <i>Astronomy &#38;
    Astrophysics</i>, vol. 706, A261, EDP Sciences, 2026, doi:<a href="https://doi.org/10.1051/0004-6361/202557358">10.1051/0004-6361/202557358</a>.'
  short: A. Giménez-Alcázar, R. Amorín, J.M. Vílchez, A. Hernán-Caballero, M. González-Otero,
    A. Arroyo-Polonio, J. Iglesias-Páramo, A. Lumbreras-Calle, J.A. Fernández-Ontiveros,
    C. López-Sanjuan, L. Bonatto, R.M. González Delgado, C. Kehrig, A. Torralba Torregrosa,
    P.T. Rahna, Y. Jiménez-Teja, I. Márquez, I. Breda, A. Álvarez-Candal, R. Abramo,
    J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, J. Cenarro, D. Cristóbal-Hornillos,
    R. Dupke, A. Ederoclite, C. Hernández-Monteagudo, A. Marín-Franch, C. Mendes de
    Oliveira, M. Moles, L. Sodré, K. Taylor, J. Varela, H. Vázquez Ramió, Astronomy
    &#38; Astrophysics 706 (2026).
date_created: 2026-03-02T10:06:10Z
date_published: 2026-02-01T00:00:00Z
date_updated: 2026-03-02T15:10:27Z
day: '01'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.1051/0004-6361/202557358
external_id:
  arxiv:
  - '2512.08484'
file:
- access_level: open_access
  checksum: cd25a05386ab5638ae5baf8add0ecbee
  content_type: application/pdf
  creator: dernst
  date_created: 2026-03-02T14:51:57Z
  date_updated: 2026-03-02T14:51:57Z
  file_id: '21391'
  file_name: 2026_AstronomyAstrophysics_GimenezAlcazar.pdf
  file_size: 1813456
  relation: main_file
  success: 1
file_date_updated: 2026-03-02T14:51:57Z
has_accepted_license: '1'
intvolume: '       706'
language:
- iso: eng
month: '02'
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: 'J-PAS: First identification, physical properties, and ionization efficiency
  of extreme emission line galaxies'
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: 706
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '21451'
abstract:
- lang: eng
  text: The population of the little red dots (LRDs) may represent a key phase of
    supermassive black hole (SMBH) growth. A cocoon of dense excited gas is emerging
    as a key component to explain the most striking properties of LRDs, such as strong
    Balmer breaks and Balmer absorption, as well as the weak IR emission. To dissect
    the structure of LRDs, we analyzed new deep JWST/NIRSpec PRISM and G395H spectra
    of FRESCO-GN-9771, one of the most luminous known LRDs at z = 5.5. These spectra
    reveal a strong Balmer break, broad Balmer lines, and very narrow [O III] emission.
    We revealed a forest of optical [Fe II] lines, which we argue are emerging from
    a dense (nH = 109 − 10 cm−3) warm layer with electron temperature Te ≈ 7000 K.
    The broad wings of Hα and Hβ have an exponential profile due to electron scattering
    in this same layer. The high Hα : Hβ : Hγ flux ratio of ≈10.4 : 1 : 0.14 is an
    indicator of collisional excitation and resonant scattering dominating the Balmer
    line emission. A narrow Hγ component, unseen in the other two Balmer lines due
    to outshining by the broad components, could trace the ISM of a normal host galaxy
    with a star formation rate of ∼5 M⊙ yr−1. The warm layer is mostly opaque to Balmer
    transitions, producing a characteristic P Cygni profile in the line centers suggesting
    outflowing motions. This same layer is responsible for shaping the Balmer break.
    The broadband spectrum can be reasonably matched by a simple photoionized slab
    model that dominates the λ > 1500 Å continuum and a low-mass (∼108 M⊙) galaxy
    that could explain the narrow [O III], with only a subdominant contribution to
    the UV continuum. Our findings indicate that Balmer lines are not directly tracing
    the gas kinematics near the SMBH and that the BH mass scale is likely much lower
    than virial indicators suggest.
acknowledgement: 'We thank the scientific referee for useful and constructive comments.
  We thank Ylva Götberg and Zoltan Haiman for insightful discussions about the physics
  of gaseous envelopes and accretion into black holes. Funded by the European Union
  (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the
  author(s) 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. This 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 program #5664. This work has received funding from the Swiss State Secretariat
  for Education, Research and Innovation (SERI) under contract number MB22.00072,
  as well as from the Swiss National Science Foundation (SNSF) through project grant
  200020_207349.'
article_number: A75
article_processing_charge: No
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: Gabriele
  full_name: Pezzulli, Gabriele
  last_name: Pezzulli
- first_name: Rohan P.
  full_name: Naidu, Rohan P.
  last_name: Naidu
- first_name: Yuzo
  full_name: Ishikawa, Yuzo
  last_name: Ishikawa
- first_name: Gabriel B.
  full_name: Brammer, Gabriel B.
  last_name: Brammer
- first_name: Seok Jun
  full_name: Chang, Seok Jun
  last_name: Chang
- first_name: John
  full_name: Chisholm, John
  last_name: Chisholm
- first_name: Anna
  full_name: De Graaff, Anna
  last_name: De Graaff
- first_name: Francesco
  full_name: D’Eugenio, Francesco
  last_name: D’Eugenio
- first_name: Claudia
  full_name: Di Cesare, Claudia
  id: 2d002343-372f-11ef-98ec-a164d20427cb
  last_name: Di Cesare
- first_name: Anna Christina
  full_name: Eilers, Anna Christina
  last_name: Eilers
- first_name: Jenny E.
  full_name: Greene, Jenny E.
  last_name: Greene
- first_name: Max
  full_name: Gronke, Max
  last_name: Gronke
- first_name: Edoardo
  full_name: Iani, Edoardo
  id: 4053390a-6b68-11ef-9828-a3b8adef8d0a
  last_name: Iani
  orcid: 0000-0001-8386-3546
- first_name: Vasily
  full_name: Kokorev, Vasily
  last_name: Kokorev
- first_name: Gauri
  full_name: Kotiwale, Gauri
  id: 1438afc8-1ff6-11ee-9fa6-cd4a75d66875
  last_name: Kotiwale
- first_name: Ivan
  full_name: Kramarenko, Ivan
  id: 9a9394cb-3200-11ee-973b-f5ba2a8b16e4
  last_name: Kramarenko
  orcid: 0000-0001-5346-6048
- first_name: Yilun
  full_name: Ma, Yilun
  last_name: Ma
- first_name: Sara
  full_name: Mascia, Sara
  id: edaf889c-c7cd-11ef-ab1b-bb28c431bd29
  last_name: Mascia
- first_name: Benjamín
  full_name: Navarrete, Benjamín
  id: aa14a535-50c9-11ef-b52e-e0c373d10148
  last_name: Navarrete
- first_name: Erica
  full_name: Nelson, Erica
  last_name: Nelson
- first_name: Pascal
  full_name: Oesch, Pascal
  last_name: Oesch
- first_name: Robert A.
  full_name: Simcoe, Robert A.
  last_name: Simcoe
- first_name: Stijn
  full_name: Wuyts, Stijn
  last_name: Wuyts
citation:
  ama: Torralba Torregrosa A, Matthee JJ, Pezzulli G, et al. The warm outer layer
    of a little red dot as the source of [Fe ii] and collisional Balmer lines with
    scattering wings. <i>Astronomy &#38; Astrophysics</i>. 2026;707. doi:<a href="https://doi.org/10.1051/0004-6361/202557537">10.1051/0004-6361/202557537</a>
  apa: Torralba Torregrosa, A., Matthee, J. J., Pezzulli, G., Naidu, R. P., Ishikawa,
    Y., Brammer, G. B., … Wuyts, S. (2026). The warm outer layer of a little red dot
    as the source of [Fe ii] and collisional Balmer lines with scattering wings. <i>Astronomy
    &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202557537">https://doi.org/10.1051/0004-6361/202557537</a>
  chicago: Torralba Torregrosa, Alberto, Jorryt J Matthee, Gabriele Pezzulli, Rohan
    P. Naidu, Yuzo Ishikawa, Gabriel B. Brammer, Seok Jun Chang, et al. “The Warm
    Outer Layer of a Little Red Dot as the Source of [Fe Ii] and Collisional Balmer
    Lines with Scattering Wings.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences,
    2026. <a href="https://doi.org/10.1051/0004-6361/202557537">https://doi.org/10.1051/0004-6361/202557537</a>.
  ieee: A. Torralba Torregrosa <i>et al.</i>, “The warm outer layer of a little red
    dot as the source of [Fe ii] and collisional Balmer lines with scattering wings,”
    <i>Astronomy &#38; Astrophysics</i>, vol. 707. EDP Sciences, 2026.
  ista: Torralba Torregrosa A, Matthee JJ, Pezzulli G, Naidu RP, Ishikawa Y, Brammer
    GB, Chang SJ, Chisholm J, De Graaff A, D’Eugenio F, Di Cesare C, Eilers AC, Greene
    JE, Gronke M, Iani E, Kokorev V, Kotiwale G, Kramarenko I, Ma Y, Mascia S, Navarrete
    B, Nelson E, Oesch P, Simcoe RA, Wuyts S. 2026. The warm outer layer of a little
    red dot as the source of [Fe ii] and collisional Balmer lines with scattering
    wings. Astronomy &#38; Astrophysics. 707, A75.
  mla: Torralba Torregrosa, Alberto, et al. “The Warm Outer Layer of a Little Red
    Dot as the Source of [Fe Ii] and Collisional Balmer Lines with Scattering Wings.”
    <i>Astronomy &#38; Astrophysics</i>, vol. 707, A75, EDP Sciences, 2026, doi:<a
    href="https://doi.org/10.1051/0004-6361/202557537">10.1051/0004-6361/202557537</a>.
  short: A. Torralba Torregrosa, J.J. Matthee, G. Pezzulli, R.P. Naidu, Y. Ishikawa,
    G.B. Brammer, S.J. Chang, J. Chisholm, A. De Graaff, F. D’Eugenio, C. Di Cesare,
    A.C. Eilers, J.E. Greene, M. Gronke, E. Iani, V. Kokorev, G. Kotiwale, I. Kramarenko,
    Y. Ma, S. Mascia, B. Navarrete, E. Nelson, P. Oesch, R.A. Simcoe, S. Wuyts, Astronomy
    &#38; Astrophysics 707 (2026).
corr_author: '1'
date_created: 2026-03-15T23:01:36Z
date_published: 2026-03-01T00:00:00Z
date_updated: 2026-03-16T10:59:16Z
day: '01'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.1051/0004-6361/202557537
external_id:
  arxiv:
  - '2510.00103'
file:
- access_level: open_access
  checksum: fcab9cb3dcf1d68612e1fdc8191643c1
  content_type: application/pdf
  creator: dernst
  date_created: 2026-03-16T10:57:49Z
  date_updated: 2026-03-16T10:57:49Z
  file_id: '21460'
  file_name: 2026_AstronomyAstrophysics_Torralba2.pdf
  file_size: 2510157
  relation: main_file
  success: 1
file_date_updated: 2026-03-16T10:57:49Z
has_accepted_license: '1'
intvolume: '       707'
language:
- iso: eng
month: '03'
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: 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: The warm outer layer of a little red dot as the source of [Fe ii] and collisional
  Balmer lines with scattering wings
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'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21846'
abstract:
- lang: eng
  text: 'We compile a sample of 83 little red dots (LRDs) with JWST imaging and find
    that a substantial fraction (∼43%, rising to ≳80% for the most luminous LRDs)
    host one or more spatially offset, UV-bright companions at projected separations
    of 0.5 kpc ≲ d ≲ 5 kpc, with median 〈d〉 = 1.0 kpc. This fraction is even higher
    when smaller spatial scales are probed at high signal-to-noise ratio: the two
    most strongly lensed LRDs, A383-LRD1 and the newly discovered A68-LRD1, both have
    UV-bright companions at separations of only d ∼ 0.3 kpc, below the resolution
    limit of most unlensed JWST samples. We explore whether these ubiquitous red/blue
    configurations may be physically linked to the formation of LRDs, in analogy with
    the “synchronized pair” scenario originally proposed for direct-collapse black
    hole formation. In this picture, UV radiation from the companions, with typically
    modest stellar masses (M∗ ∼ 108−109 M⊙), suppresses molecular hydrogen cooling
    in nearby gas, allowing nearly isothermal collapse and the formation of extremely
    compact objects, such as massive black holes, supermassive stars, or quasi-stars.
    Using component-resolved photometry and spectral energy distribution modeling,
    we infer Lyman–Werner radiation fields of J21,LW ∼ 102.5–105 at the locations
    of the red components, comparable to those required in direct-collapse models,
    suggesting that the necessary photodissociation conditions are realized in many
    LRD systems. This framework provides a simple and self-consistent explanation
    for the extreme compactness and distinctive spectral properties of LRDs and links
    long-standing theoretical models for early compact object formation directly to
    a population now observed with JWST in the early Universe.'
acknowledgement: 'We thank Earl Bellinger, Fabio Pacucci, Andrea Ferrara, and Dale
  Kocevski for useful discussions. 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 imaging observations are associated with
  programs 1345, 1180, 1181, 1243, 6882, 2561, 1324, 4111, and 1895. The compiled
  dataset can be accessed at doi:10.17909/1m8f-9c47. The Cosmic Dawn Center (DAWN)
  is funded by the Danish National Research Foundation under grant DNRF140. J.M. and
  A.T. acknowledge funding by the European Union (ERC, AGENTS, 101076224). This work
  was performed in part at Aspen Center for Physics, which is supported by National
  Science Foundation grant PHY-2210452. This work used the following Python packages:
  Matplotlib (J. D. Hunter 2007), SciPy (P. Virtanen et al. 2020), NumPy (S. van der
  Walt et al. 2011), AstroPy (Astropy Collaboration et al. 2022), colossus (B. Diemer
  2018), and photutils (L. Bradley et al. 2025).'
article_number: L4
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Josephine F.W.
  full_name: Baggen, Josephine F.W.
  last_name: Baggen
- first_name: Matthew T.
  full_name: Scoggins, Matthew T.
  last_name: Scoggins
- first_name: Pieter
  full_name: Van Dokkum, Pieter
  last_name: Van Dokkum
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
  orcid: 0000-0003-3633-5403
- 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
citation:
  ama: 'Baggen JFW, Scoggins MT, Van Dokkum P, Haiman Z, Torralba Torregrosa A, Matthee
    JJ. Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner
    sources enabling direct-collapse Black Hole formation. <i>The Astrophysical Journal
    Letters</i>. 2026;1002(1). doi:<a href="https://doi.org/10.3847/2041-8213/ae58a5">10.3847/2041-8213/ae58a5</a>'
  apa: 'Baggen, J. F. W., Scoggins, M. T., Van Dokkum, P., Haiman, Z., Torralba Torregrosa,
    A., &#38; Matthee, J. J. (2026). Connecting the dots: UV-bright companions of
    Little Red Dots as Lyman–Werner sources enabling direct-collapse Black Hole formation.
    <i>The Astrophysical Journal Letters</i>. IOP Publishing. <a href="https://doi.org/10.3847/2041-8213/ae58a5">https://doi.org/10.3847/2041-8213/ae58a5</a>'
  chicago: 'Baggen, Josephine F.W., Matthew T. Scoggins, Pieter Van Dokkum, Zoltán
    Haiman, Alberto Torralba Torregrosa, and Jorryt J Matthee. “Connecting the Dots:
    UV-Bright Companions of Little Red Dots as Lyman–Werner Sources Enabling Direct-Collapse
    Black Hole Formation.” <i>The Astrophysical Journal Letters</i>. IOP Publishing,
    2026. <a href="https://doi.org/10.3847/2041-8213/ae58a5">https://doi.org/10.3847/2041-8213/ae58a5</a>.'
  ieee: 'J. F. W. Baggen, M. T. Scoggins, P. Van Dokkum, Z. Haiman, A. Torralba Torregrosa,
    and J. J. Matthee, “Connecting the dots: UV-bright companions of Little Red Dots
    as Lyman–Werner sources enabling direct-collapse Black Hole formation,” <i>The
    Astrophysical Journal Letters</i>, vol. 1002, no. 1. IOP Publishing, 2026.'
  ista: 'Baggen JFW, Scoggins MT, Van Dokkum P, Haiman Z, Torralba Torregrosa A, Matthee
    JJ. 2026. Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner
    sources enabling direct-collapse Black Hole formation. The Astrophysical Journal
    Letters. 1002(1), L4.'
  mla: 'Baggen, Josephine F. W., et al. “Connecting the Dots: UV-Bright Companions
    of Little Red Dots as Lyman–Werner Sources Enabling Direct-Collapse Black Hole
    Formation.” <i>The Astrophysical Journal Letters</i>, vol. 1002, no. 1, L4, IOP
    Publishing, 2026, doi:<a href="https://doi.org/10.3847/2041-8213/ae58a5">10.3847/2041-8213/ae58a5</a>.'
  short: J.F.W. Baggen, M.T. Scoggins, P. Van Dokkum, Z. Haiman, A. Torralba Torregrosa,
    J.J. Matthee, The Astrophysical Journal Letters 1002 (2026).
date_created: 2026-05-10T22:02:15Z
date_published: 2026-04-10T00:00:00Z
date_updated: 2026-05-11T06:48:33Z
day: '10'
ddc:
- '520'
department:
- _id: ZoHa
- _id: JoMa
doi: 10.3847/2041-8213/ae58a5
external_id:
  arxiv:
  - '2602.02702'
file:
- access_level: open_access
  checksum: 8c31d8603cd6ad39c772a72d136dc3f8
  content_type: application/pdf
  creator: dernst
  date_created: 2026-05-11T06:44:37Z
  date_updated: 2026-05-11T06:44:37Z
  file_id: '21851'
  file_name: 2026_AstrophysicalJourLetters_Baggen.pdf
  file_size: 13359642
  relation: main_file
  success: 1
file_date_updated: 2026-05-11T06:44:37Z
has_accepted_license: '1'
intvolume: '      1002'
issue: '1'
language:
- iso: eng
month: '04'
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'
scopus_import: '1'
status: public
title: 'Connecting the dots: UV-bright companions of Little Red Dots as Lyman–Werner
  sources enabling direct-collapse Black Hole formation'
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: 1002
year: '2026'
...
---
OA_place: publisher
OA_type: diamond
_id: '19929'
abstract:
- lang: eng
  text: "Context. The observed Lyman-alpha (Lyα) line profile is a convolution of
    the complex Lyα radiative transfer taking place in the interstellar, circumgalactic,
    and intergalactic media (ISM, CGM, and IGM, respectively). Discerning the different
    components of the Lyα line is crucial in order to use it as a probe of galaxy
    formation or the evolution of the IGM.\r\n\r\nAims. We aim to present the second
    version of zELDA (redshift Estimator for Line profiles of Distant Lyman-Alpha
    emitters), an open-source Python module focused on modelling and fitting observed
    Lyα line profiles. This new version of zELDA focuses on disentangling the galactic
    from the IGM effects.\r\n\r\nMethods. We built realistic Lyα line profiles that
    include the ISM and IGM contributions by combining the Monte Carlo radiative-transfer
    simulations for the so-called shell model (ISM) and IGM transmission curves generated
    from TNG100. We used these mock line profiles to train different artificial neural
    networks. These use the observed spectrum as input and the outflow parameters
    of the best fitting ‘shell model’ as output along with the redshift and Lyα emission
    IGM escape fraction of the source.\r\n\r\nResults. We measured the accuracy of
    zELDA on mock Lyα line profiles. We find that zELDA is capable of reconstructing
    the ISM emerging Lyα line profile with high levels of accuracy (Kolmogórov-Smirnov<0.1)
    for 95% of the cases for HST/COS-like observations and 80% for MUSE-WIDE-like
    observations. zELDA is able to measure the IGM transmission with typical uncertainties
    below 10% for HST/COS and MUSE-WIDE data.\r\n\r\nConclusions. This work represents
    a step forward in the high-precision reconstruction of IGM-attenuated Lyα line
    profiles. zELDA allows the disentanglement of the galactic and IGM contribution
    shaping the Lyα line shape and thus allows us to use Lyα as a tool to study galaxy
    and ISM evolution."
acknowledgement: The authors acknowledge the financial support from the MICIU with
  funding from the European Union NextGenerationEU and Generalitat Valenciana in the
  call Programa de Planes Complementarios de I+D+i (PRTR 2022) Project (VAL-JPAS),
  reference ASFAE/2022/025. This work is part of the research Project PID2023-149420NB-I00
  funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU. This work is also supported
  by the project of excellence PROMETEO CIPROM/2023/21 of the Conselleria de Educación,
  Universidades y Empleo (Generalitat Valenciana). MG thanks the Max Planck Society
  for support through the Max Planck Research Group. DS acknowledges the support by
  the Tsinghua Shui Mu Scholarship, funding of the National Key R&D Program of China
  (grant no. 2023YFA1605600), the science research grants from the China Manned Space
  Project with no. CMS-CSST2021-A05, and the Tsinghua University Initiative Scientific
  Research Program (no. 20223080023). This research made use of matplotlib, a Python
  library for publication quality graphics (Hunter 2007), NumPy (Harris et al. 2020)
  and SciPy (Virtanen et al. 2020).
article_number: A139
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Siddhartha
  full_name: Gurung-López, Siddhartha
  last_name: Gurung-López
- first_name: Chris
  full_name: Byrohl, Chris
  last_name: Byrohl
- first_name: Max
  full_name: Gronke, Max
  last_name: Gronke
- first_name: Daniele
  full_name: Spinoso, Daniele
  last_name: Spinoso
- 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: Alberto
  full_name: Fernández-Soto, Alberto
  last_name: Fernández-Soto
- first_name: Pablo
  full_name: Arnalte-Mur, Pablo
  last_name: Arnalte-Mur
- first_name: Vicent J.
  full_name: Martínez, Vicent J.
  last_name: Martínez
citation:
  ama: 'Gurung-López S, Byrohl C, Gronke M, et al. zELDA II: Reconstruction of galactic
    Lyman-alpha spectra attenuated by the intergalactic medium using neural networks.
    <i>Astronomy &#38; Astrophysics</i>. 2025;698. doi:<a href="https://doi.org/10.1051/0004-6361/202453547">10.1051/0004-6361/202453547</a>'
  apa: 'Gurung-López, S., Byrohl, C., Gronke, M., Spinoso, D., Torralba Torregrosa,
    A., Fernández-Soto, A., … Martínez, V. J. (2025). zELDA II: Reconstruction of
    galactic Lyman-alpha spectra attenuated by the intergalactic medium using neural
    networks. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202453547">https://doi.org/10.1051/0004-6361/202453547</a>'
  chicago: 'Gurung-López, Siddhartha, Chris Byrohl, Max Gronke, Daniele Spinoso, Alberto
    Torralba Torregrosa, Alberto Fernández-Soto, Pablo Arnalte-Mur, and Vicent J.
    Martínez. “ZELDA II: Reconstruction of Galactic Lyman-Alpha Spectra Attenuated
    by the Intergalactic Medium Using Neural Networks.” <i>Astronomy &#38; Astrophysics</i>.
    EDP Sciences, 2025. <a href="https://doi.org/10.1051/0004-6361/202453547">https://doi.org/10.1051/0004-6361/202453547</a>.'
  ieee: 'S. Gurung-López <i>et al.</i>, “zELDA II: Reconstruction of galactic Lyman-alpha
    spectra attenuated by the intergalactic medium using neural networks,” <i>Astronomy
    &#38; Astrophysics</i>, vol. 698. EDP Sciences, 2025.'
  ista: 'Gurung-López S, Byrohl C, Gronke M, Spinoso D, Torralba Torregrosa A, Fernández-Soto
    A, Arnalte-Mur P, Martínez VJ. 2025. zELDA II: Reconstruction of galactic Lyman-alpha
    spectra attenuated by the intergalactic medium using neural networks. Astronomy
    &#38; Astrophysics. 698, A139.'
  mla: 'Gurung-López, Siddhartha, et al. “ZELDA II: Reconstruction of Galactic Lyman-Alpha
    Spectra Attenuated by the Intergalactic Medium Using Neural Networks.” <i>Astronomy
    &#38; Astrophysics</i>, vol. 698, A139, EDP Sciences, 2025, doi:<a href="https://doi.org/10.1051/0004-6361/202453547">10.1051/0004-6361/202453547</a>.'
  short: S. Gurung-López, C. Byrohl, M. Gronke, D. Spinoso, A. Torralba Torregrosa,
    A. Fernández-Soto, P. Arnalte-Mur, V.J. Martínez, Astronomy &#38; Astrophysics
    698 (2025).
date_created: 2025-06-29T22:01:15Z
date_published: 2025-06-01T00:00:00Z
date_updated: 2026-02-16T12:11:56Z
day: '01'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.1051/0004-6361/202453547
external_id:
  arxiv:
  - '2501.04077'
  isi:
  - '001507317300003'
file:
- access_level: open_access
  checksum: a50a817b72f03534c6a867035b51e433
  content_type: application/pdf
  creator: dernst
  date_created: 2025-06-30T08:28:40Z
  date_updated: 2025-06-30T08:28:40Z
  file_id: '19933'
  file_name: 2025_AstronomyAstrophysics_GurungLopez.pdf
  file_size: 5758102
  relation: main_file
  success: 1
file_date_updated: 2025-06-30T08:28:40Z
has_accepted_license: '1'
intvolume: '       698'
isi: 1
language:
- iso: eng
month: '06'
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: 'zELDA II: Reconstruction of galactic Lyman-alpha spectra attenuated by the
  intergalactic medium using neural networks'
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: 698
year: '2025'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21062'
abstract:
- lang: eng
  text: JWST observations have unveiled faint active galactic nuclei (AGNs) at high
    redshift that provide insights into the formation of supermassive black holes
    (SMBHs). However, disentangling their stellar from AGN light is challenging. Here,
    we use an empirical approach to infer the average stellar mass of five faint broad-line
    (BL) Hα emitters at z = 4–5 with BH masses ≈6 × 10^6 M⊙, with a method independent
    of their spectral energy distribution (SED). We use the deep JWST/NIRcam grism
    survey “All the Little Things” to measure the overdensities around BL-Hα emitters
    and around a spectroscopic reference sample of ∼300 galaxies. In our reference
    sample, we find that megaparsec-scale overdensity correlates with stellar mass.
    Their large-scale environments suggest that BL-Hα emitters are hosted by galaxies
    with stellar masses ≈5 × 10^7 M⊙, ≈40 times lower than those inferred from galaxy-only
    SED fits. Adding measurements around more luminous z ≈ 6 AGNs, we find tentative
    correlations between line width, BH mass, and the overdensity, suggestive of a
    steep BH to halo mass relation. The main implications are (1) when BH masses are
    taken at face value, we confirm extremely high BH to stellar mass ratios of ≈10%,
    (2) the galaxies of low stellar mass that host growing SMBHs are in tension with
    typical hydrodynamical simulations, except those without feedback, (3) a 1% duty
    cycle implied by the host mass hints at super-Eddington accretion, (4) the masses
    are at odds with an interpretation of the line broadening in terms of high stellar
    density, (5) our results imply a luminosity-dependent diversity of galaxy masses,
    environments, and SEDs among AGN samples.
acknowledgement: 'We thank the referee for their constructive comments that helped
  to improve the paper. We thank Junyao Li for sharing model output shown in Figure
  13, Rob Crain for sharing results from the ONLYAGN EAGLE model shown in Figure 15,
  and Adi Zitrin for comments. 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 programs # 3516. Funded
  by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are
  however those of the author(s) 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. We acknowledge funding
  from JWST program GO-3516. Support for this work was provided by NASA through the
  NASA Hubble Fellowship grant HST-HF2-51515.001-A awarded by the Space Telescope
  Science Institute, which is operated by the Association of Universities for Research
  in Astronomy, Incorporated, under NASA contract NAS 5-26555. A.A. acknowledges support
  by the Swedish research council Vetenskapsrådet (2021-05559).'
article_number: '246'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- 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: Rohan P.
  full_name: Naidu, Rohan P.
  last_name: Naidu
- first_name: Gauri
  full_name: Kotiwale, Gauri
  id: 1438afc8-1ff6-11ee-9fa6-cd4a75d66875
  last_name: Kotiwale
- first_name: Lukas J.
  full_name: Furtak, Lukas J.
  last_name: Furtak
- first_name: Ivan
  full_name: Kramarenko, Ivan
  id: 9a9394cb-3200-11ee-973b-f5ba2a8b16e4
  last_name: Kramarenko
  orcid: 0000-0001-5346-6048
- first_name: Ruari
  full_name: Mackenzie, Ruari
  last_name: Mackenzie
- first_name: Jenny
  full_name: Greene, Jenny
  last_name: Greene
- first_name: Angela
  full_name: Adamo, Angela
  last_name: Adamo
- first_name: Rychard J.
  full_name: Bouwens, Rychard J.
  last_name: Bouwens
- first_name: Claudia
  full_name: Di Cesare, Claudia
  id: 2d002343-372f-11ef-98ec-a164d20427cb
  last_name: Di Cesare
- first_name: Anna-Christina
  full_name: Eilers, Anna-Christina
  last_name: Eilers
- first_name: Anna
  full_name: de Graaff, Anna
  last_name: de Graaff
- first_name: Kasper E.
  full_name: Heintz, Kasper E.
  last_name: Heintz
- first_name: Daichi
  full_name: Kashino, Daichi
  last_name: Kashino
- first_name: Michael V.
  full_name: Maseda, Michael V.
  last_name: Maseda
- first_name: Sandro
  full_name: Tacchella, Sandro
  last_name: Tacchella
- first_name: Alberto
  full_name: Torralba Torregrosa, Alberto
  id: 018f0249-0e87-11f0-b167-cbce08fbd541
  last_name: Torralba Torregrosa
  orcid: 0000-0001-5586-6950
citation:
  ama: Matthee JJ, Naidu RP, Kotiwale G, et al. Environmental evidence for overly
    massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at
    z ∼ 5. <i>The Astrophysical Journal</i>. 2025;988(2). doi:<a href="https://doi.org/10.3847/1538-4357/ade886">10.3847/1538-4357/ade886</a>
  apa: Matthee, J. J., Naidu, R. P., Kotiwale, G., Furtak, L. J., Kramarenko, I.,
    Mackenzie, R., … Torralba Torregrosa, A. (2025). Environmental evidence for overly
    massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at
    z ∼ 5. <i>The Astrophysical Journal</i>. IOP Publishing. <a href="https://doi.org/10.3847/1538-4357/ade886">https://doi.org/10.3847/1538-4357/ade886</a>
  chicago: Matthee, Jorryt J, Rohan P. Naidu, Gauri Kotiwale, Lukas J. Furtak, Ivan
    Kramarenko, Ruari Mackenzie, Jenny Greene, et al. “Environmental Evidence for
    Overly Massive Black Holes in Low-Mass Galaxies and a Black Hole–Halo Mass Relation
    at z ∼ 5.” <i>The Astrophysical Journal</i>. IOP Publishing, 2025. <a href="https://doi.org/10.3847/1538-4357/ade886">https://doi.org/10.3847/1538-4357/ade886</a>.
  ieee: J. J. Matthee <i>et al.</i>, “Environmental evidence for overly massive Black
    Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5,” <i>The
    Astrophysical Journal</i>, vol. 988, no. 2. IOP Publishing, 2025.
  ista: Matthee JJ, Naidu RP, Kotiwale G, Furtak LJ, Kramarenko I, Mackenzie R, Greene
    J, Adamo A, Bouwens RJ, Di Cesare C, Eilers A-C, de Graaff A, Heintz KE, Kashino
    D, Maseda MV, Tacchella S, Torralba Torregrosa A. 2025. Environmental evidence
    for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass
    relation at z ∼ 5. The Astrophysical Journal. 988(2), 246.
  mla: Matthee, Jorryt J., et al. “Environmental Evidence for Overly Massive Black
    Holes in Low-Mass Galaxies and a Black Hole–Halo Mass Relation at z ∼ 5.” <i>The
    Astrophysical Journal</i>, vol. 988, no. 2, 246, IOP Publishing, 2025, doi:<a
    href="https://doi.org/10.3847/1538-4357/ade886">10.3847/1538-4357/ade886</a>.
  short: J.J. Matthee, R.P. Naidu, G. Kotiwale, L.J. Furtak, I. Kramarenko, R. Mackenzie,
    J. Greene, A. Adamo, R.J. Bouwens, C. Di Cesare, A.-C. Eilers, A. de Graaff, K.E.
    Heintz, D. Kashino, M.V. Maseda, S. Tacchella, A. Torralba Torregrosa, The Astrophysical
    Journal 988 (2025).
corr_author: '1'
date_created: 2026-01-28T15:25:42Z
date_published: 2025-07-29T00:00:00Z
date_updated: 2026-02-09T08:22:01Z
day: '29'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.3847/1538-4357/ade886
external_id:
  arxiv:
  - '2412.02846'
file:
- access_level: open_access
  checksum: a49fbed72f2ff9c0b13129acb6f44f9d
  content_type: application/pdf
  creator: dernst
  date_created: 2026-02-09T08:20:14Z
  date_updated: 2026-02-09T08:20:14Z
  file_id: '21168'
  file_name: 2025_AstrophysicalJournal_Matthee.pdf
  file_size: 6237415
  relation: main_file
  success: 1
file_date_updated: 2026-02-09T08:20:14Z
has_accepted_license: '1'
intvolume: '       988'
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
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Environmental evidence for overly massive Black Holes in low-mass galaxies
  and a Black Hole–Halo mass relation at z ∼ 5
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: 988
year: '2025'
...