---
OA_place: repository
OA_type: green
_id: '21933'
abstract:
- lang: eng
text: We consider the liquid drop model with a positive background density in the
thermodynamic limit. We prove a two-term asymptotics for the ground state energy
per unit volume in the dilute limit. Our proof justifies the expectation that
optimal configurations consist of droplets of unit size that arrange themselves
according to minimizers for the Jellium problem for point particles. In particular,
we provide the first rigorous derivation of what is known as the gnocchi phase
in astrophysics.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Rupert L.
full_name: Frank, Rupert L.
last_name: Frank
- first_name: Mathieu
full_name: Lewin, Mathieu
last_name: Lewin
- first_name: Robert
full_name: Seiringer, Robert
id: 4AFD0470-F248-11E8-B48F-1D18A9856A87
last_name: Seiringer
orcid: 0000-0002-6781-0521
citation:
ama: Frank RL, Lewin M, Seiringer R. Liquid drop model for nuclear matter in the
low density limit. Communications on Pure and Applied Mathematics. 2026.
doi:10.1002/cpa.70039
apa: Frank, R. L., Lewin, M., & Seiringer, R. (2026). Liquid drop model for
nuclear matter in the low density limit. Communications on Pure and Applied
Mathematics. Wiley. https://doi.org/10.1002/cpa.70039
chicago: Frank, Rupert L., Mathieu Lewin, and Robert Seiringer. “Liquid Drop Model
for Nuclear Matter in the Low Density Limit.” Communications on Pure and Applied
Mathematics. Wiley, 2026. https://doi.org/10.1002/cpa.70039.
ieee: R. L. Frank, M. Lewin, and R. Seiringer, “Liquid drop model for nuclear matter
in the low density limit,” Communications on Pure and Applied Mathematics.
Wiley, 2026.
ista: Frank RL, Lewin M, Seiringer R. 2026. Liquid drop model for nuclear matter
in the low density limit. Communications on Pure and Applied Mathematics.
mla: Frank, Rupert L., et al. “Liquid Drop Model for Nuclear Matter in the Low Density
Limit.” Communications on Pure and Applied Mathematics, Wiley, 2026, doi:10.1002/cpa.70039.
short: R.L. Frank, M. Lewin, R. Seiringer, Communications on Pure and Applied Mathematics
(2026).
date_created: 2026-05-31T22:02:13Z
date_published: 2026-01-01T00:00:00Z
date_updated: 2026-06-02T06:58:54Z
day: '01'
department:
- _id: RoSe
doi: 10.1002/cpa.70039
external_id:
arxiv:
- '2507.14012'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.48550/arXiv.2507.14012
month: '01'
oa: 1
oa_version: Preprint
publication: Communications on Pure and Applied Mathematics
publication_identifier:
eissn:
- 1097-0312
issn:
- 0010-3640
publication_status: epub_ahead
publisher: Wiley
scopus_import: '1'
status: public
title: Liquid drop model for nuclear matter in the low density limit
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: '21930'
abstract:
- lang: eng
text: "We present the discovery of extreme nitrogen enrichment by Wolf Rayet nitrogen
(WN) stars in the metal-poor (∼10%Z⊙), lensed, compact (Reff ∼ 20 pc) galaxy RXCJ2248
at z = 6.1, revealed by unprecedentedly deep\r\nJWST/NIRSpec medium-resolution
spectroscopy from the GLIMPSE-D Survey. The exquisite signal-to-noise\r\nratio
reveals multiple high-ionization nebular lines and broad Balmer and [O III] components
(FWHM\r\n∼700–3000 km s\r\n−1\r\n). We detect broadened He II λ1640 and λ4687
(FWHM ∼ 530 km s\r\n−1\r\n) and strong N III λ4642\r\nemission consistent with
a population of WN stars, making RXCJ2248 the most distant galaxy with confirmed\r\nWolf
Rayet (WR) features to date. We measure the multiphase nebular density across
five ions, the direct-method\r\nmetallicity (\r\n12 + log(O/H) = 7.753 ± 0.025\r\n),
and a nonuniform elemental enrichment pattern of extreme N/O\r\nenhancement (\r\nlog(N/O)
= 0.391 ± 0.037\r\nfrom N+, N+2\r\n, and N+3\r\n) but suppressed C/O relative
to empirical\r\nC/N trends. We show that this abundance pattern can be explained
by enrichment from a dual-burst with a low\r\nWR carbon/WN ratio, as expected
at low metallicities. Crucially, these signatures can only arise during a brief,\r\nrare
evolutionary window shortly after a burst (∼3–6 Myr), when WN stars dominate chemical
feedback but\r\nbefore dilution by later yields (e.g., supernovae). The observed
frequency of strong N emitters at high−z implies a\r\n∼50 Myr burst duty cycle,
suggesting that N/O outliers may represent a brief but ubiquitous phase in the\r\nevolution
of highly star-forming early galaxies. The WN detection in RXCJ2248, therefore,
provides the first\r\ndirect evidence of WR-driven nitrogen enrichment in the
first billion years of the Universe and a novel timing\r\nargument for the bursty
star formation cycles that shaped galaxies at cosmic dawn."
acknowledgement: "\r\nThe American Astronomical Society, find out more.\r\n\r\nThe
following article isOpen access\r\nA Fleeting GLIMPSE of N/O Enrichment at Cosmic
Dawn: Evidence for Wolf Rayet N Stars in a z = 6.1 Galaxy\r\nDanielle A. Berg, Rohan
P. Naidu, John Chisholm, Hakim Atek, Seiji Fujimoto, Vasily Kokorev, Lukas J. Furtak,
Chiaki Kobayashi, Daniel Schaerer, Angela Adamo, Qinyue Fei, Damien Korber, Jorryt
Matthee, Rui Marques-Chaves, Zorayda Martinez, Kristen. B. W. McQuinn, Julian B.
Muñoz, Pascal A. Oesch, Alberto Saldana-Lopez, Daniel P. Stark, Mabel G. Stephenson,
and Tiger Yu-Yang HsiaoHide full author list\r\n\r\nPublished 2026 May 20 • © 2026.
The Author(s). Published by the American Astronomical Society.\r\nThe Astrophysical
Journal, Volume 1003, Number 2\r\nCitation Danielle A. Berg et al 2026 ApJ 1003
112\r\nDOI 10.3847/1538-4357/ae5e4c\r\n\r\nDownloadArticle PDFDownloadArticle ePub\r\nAuthors\r\nFigures\r\nTables\r\nReferences\r\nArticle
data\r\nDownload PDFDownload ePub\r\nArticle metrics\r\n173 Total downloads\r\n\r\nShare
this article\r\nArticle information\r\nAbstract\r\nWe present the discovery of extreme
nitrogen enrichment by Wolf Rayet nitrogen (WN) stars in the metal-poor (∼10%Z⊙),
lensed, compact (Reff ∼ 20 pc) galaxy RXCJ2248 at z = 6.1, revealed by unprecedentedly
deep JWST/NIRSpec medium-resolution spectroscopy from the GLIMPSE-D Survey. The
exquisite signal-to-noise ratio reveals multiple high-ionization nebular lines and
broad Balmer and [O iii] components (FWHM ∼700–3000 km s−1). We detect broadened
He ii λ1640 and λ4687 (FWHM ∼ 530 km s−1) and strong N iii λ4642 emission consistent
with a population of WN stars, making RXCJ2248 the most distant galaxy with confirmed
Wolf Rayet (WR) features to date. We measure the multiphase nebular density across
five ions, the direct-method metallicity (\r\n), and a nonuniform elemental enrichment
pattern of extreme N/O enhancement (\r\n from N+, N+2, and N+3) but suppressed C/O
relative to empirical C/N trends. We show that this abundance pattern can be explained
by enrichment from a dual-burst with a low WR carbon/WN ratio, as expected at low
metallicities. Crucially, these signatures can only arise during a brief, rare evolutionary
window shortly after a burst (∼3–6 Myr), when WN stars dominate chemical feedback
but before dilution by later yields (e.g., supernovae). The observed frequency of
strong N emitters at high−z implies a ∼50 Myr burst duty cycle, suggesting that
N/O outliers may represent a brief but ubiquitous phase in the evolution of highly
star-forming early galaxies. The WN detection in RXCJ2248, therefore, provides the
first direct evidence of WR-driven nitrogen enrichment in the first billion years
of the Universe and a novel timing argument for the bursty star formation cycles
that shaped galaxies at cosmic dawn.\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\nA key
tracer of galaxy evolution is the change in their chemical composition over time.
The metallicity of a galaxy is a sensitive observational diagnostic of its past
star formation history and present-day evolutionary state given that metallicity
increases with each successive generation of massive star yields (e.g., M. Tosi
1988; J.-R. Roy & D. Kunth 1995; D. A. Berg et al. 2019; R. Maiolino & F. Mannucci
2019). Oxygen is an important tracer of metallicity because it is the most abundant
element in the Universe after H and He and is convenient to observe, with ubiquitous
emission lines from H ii regions in the rest-frame optical regime. While O emission
in dwarf and spiral galaxies has been widely observed in the rest-frame optical
and UV (e.g., R. C. Kennicutt 1992; Y. I. Izotov & T. X. Thuan 1999; L. van Zee
& M. Haynes2006; D. A. Berg et al. 2012, 2016, 2019; P. Senchyna et al. 2017; N.
S. J. Rogers et al. 2022), the N emission in these same galaxies has been predominantly
traced only in the optical through the low-ionization [N ii] λλ6550,6585 emission
lines. In general, there is a surprising dearth of detections of the high-ionization
N emission counterparts in local galaxies, totaling less than 10 galaxies with significant
detections of either N iv] λλ1483,1486 or N iii] λ1750 (e.g., M. Mingozzi et al.
2022; Z. Martinez et al. 2025). However, with the advent of JWST, there is a growing
prevalence of z ≳ 5 galaxies with extreme properties, including intense UV N emission
(e.g., A. J. Bunker et al. 2023; Y. Isobe et al. 2023; M. Castellano et al. 2024;
T. Y.-Y. Hsiao et al. 2024; X. Ji et al. 2024; R. Marques-Chaves et al. 2024; D.
Schaerer et al. 2024; M. Curti et al. 2025a; Y. Harikane et al. 2025a; R. P. Naidu
et al. 2026; M. W. Topping et al. 2025b).\r\n\r\nThe first noted, and one of the
most distant, examples of extreme rest-frame UV N emission comes from the spectroscopically
confirmed z = 10.6 galaxy, GN-z11. JWST spectra of GN-z11 revealed surprisingly
strong N iv] λλ1483,1486 and N iii] λ1750 emission (e.g., A. J. Bunker et al. 2023)
that corresponds to supersolar nitrogen-to-oxygen (N/O) enrichment (\r\n; e.g.,
A. J. Cameron et al. 2023). Subsequently, enhanced N/O has been reported in a number
of high−z galaxies, including GDS 3073 (z = 5.55; X. Ji et al. 2024), RXCJ2248-ID
(z = 6.10; M. W. Topping et al. 2024), A1703-zd6 (z = 7.04; M. W. Topping et al.
2025b), CEERS-1019 (z = 8.68; R. Marques-Chaves et al. 2024), GNz9p4 (z = 9.38;
D. Schaerer et al. 2024), GHZ9 (z = 10.15; L. Napolitano et al. 2025), GHZ2 (z =
12.34; M. Castellano et al. 2024), and MoM-z14 (z = 14.44; R. P. Naidu et al. 2026).
For a review of nitrogen line detections, see D. P. Stark et al. (2025). Such strong
nebular N+3 emission requires a relatively hard ionizing radiation field (≳47.4
eV), where models of massive stars predict few photons. On the other hand, N+2 has
a lower ionization potential (∼29.6 eV), but statistically significant detections
are strikingly rare in integrated galaxy spectra (e.g., D. A. Berg et al. 2018;
M. Mingozzi et al. 2022; A. J. Bunker et al. 2023; P. Senchyna et al. 2024) and
are only expected to be strong at the highest possible nebular temperatures (∼2.5
× 104 K). Furthermore, the timing of the incredibly high N/O abundances reported
for the high-redshift UV N emitters just a few 100 Myr after the Big Bang is unexpected.\r\n\r\nThe
discovery of significant, rapid nitrogen enhancement so early in the Universe was
surprising because it contradicts our longstanding understanding of N production.
In typical chemical evolution modeling, some nitrogen enrichment can occur early
on via core collapse supernova (CCSN), but substantial nitrogen enrichment only
occurs 100 s of megayears after the onset of star formation via asymptotic giant
branch (AGB) stars (e.g., F. Vincenzo et al. 2019; C. Kobayashi et al. 2020). Thus,
alternative, faster enrichment methods are needed to explain substantial nitrogen
enrichment in early galaxies. As a result, the necessary ionizing flux and conditions
to produce the unexpectedly strong N+3 and N+2 emission observed in galaxies beyond
z ∼ 5 have been attributed to more extreme sources, such as active galactic nuclei
(AGN; R. Maiolino et al. 2024), Wolf Rayet (WR) stars (e.g., P. Senchyna et al.
2024; K. Watanabe et al. 2024; M. L. P. Gunawardhana et al. 2025), globular cluster
precursors (e.g., C. Charbonnel et al. 2023; X. Ji et al. 2026), super star clusters
(e.g., M. Pascale et al. 2023), very massive stars (VMSs: M⋆ > 102 M⊙; e.g., J.
S. Vink 2023; Y. Shi et al. 2026), or supermassive stars (M⋆ > 103 M⊙; e.g., C.
Charbonnel et al. 2023; C. Nagele & H. Umeda 2023), tidal disruption events (e.g.,
A. J. Cameron et al. 2023; K. Watanabe et al. 2024), and more.\r\n\r\nMost of our
understanding of WR stars has been built from observations of individual resolved
stars in a handful of galaxies in the Local Group, with almost no direct spectroscopic
evidence for the prevalence of WR stars in more distant galaxies. To date, only
two systems at Cosmic Noon (z ≈ 2–3) have confirmed signatures of WR stars: MARTA-4327
at z = 2.224 (hereafter, M4327; M. Curti et al. 2025b) and the Sunburst Arc at z
= 2.37 (T. E. Rivera-Thorsen et al. 2024). Extending such detections to earlier
cosmic epochs is crucial for understanding the role of massive stars in shaping
the chemical evolution of galaxies in the first Gyr.\r\n\r\nHere, we investigate
the z = 6.1 lensed galaxy RXCJ2248-ID3. RXCJ2248-ID was first identified by F. Boone
et al. (2013), I. Balestra et al. (2013), and A. Monna et al. (2014) and discovered
to be a high-ionization, compact, metal-poor, N-enhanced galaxy by R. Mainali et
al. (2017), K. B. Schmidt et al. (2017), and M. W. Topping et al. (2024). We present
extremely deep JWST/NIRSpec observations of RXCJ2248-ID3 that provide the highest-redshift
spectroscopic evidence of WR nitrogen (WN) stars to date, which provide a physically
consistent mechanism driving its extreme nitrogen enrichment (M. W. Topping et al.
2024). The remainder of this paper is organized as follows. The observations and
data reduction are briefly described in Section 2.1, followed by a description of
the emission-line fits, including the broad lines related to the WR feedback, in
Section 2.2. We present the discovery of WN stars at z ∼ 6 via their spectral signatures
in Section 3. We determine new nebular properties and O, C, N, and Si abundances
in Section 4.3 and compare them to populations of both low- and high-redshift galaxies.
We discuss the source of N enrichment in the early Universe and subsequently estimate
mass production and timing arguments in Section 5. Finally, we present our conclusions
in Section 6. Throughout this work, we adopt cosmological parameters of H0 = 70
km s−1 Mpc−1, Ωm = 0.30, and ΩΛ = 0.7 and the solar abundance pattern from M. Asplund
et al. (2021).\r\n\r\n2. JWST/NIRSpec Spectra\r\nRXCJ2248 is a galaxy at z ∼ 6.1
that is lensed into multiple images by the Abell S1063 cluster (α = 22:48:44.13,
δ =−44:31:57.50) at a redshift of z = 0.348. We present an analysis of the brightest
image, RXCJ2248-ID3 (J = 25.0), which has a magnification of μ ∼ 7 (L. Furtak et
al. 2025). RXCJ2248-ID was discovered as a z ∼ 6 candidate (F. Boone et al. 2013;
A. Monna et al. 2014) using the 16-band HST photometry of the CLASH Survey and spectroscopically
confirmed via VIsible Multi-Object Spectrograph (VIMOS)/VLT observations by I. Balestra
et al. (2013). RXCJ2248-ID3 was soon found to be an exciting extreme emission-line
galaxy via ground-based spectroscopy (R. Mainali et al. 2017), with strong detections
of high-ionization emission such as O iii] λλ1661,1666 and C ivλλ1548,1550 but no
He ii, suggesting star formation as the ionizing source rather than an AGN.\r\n\r\nThe
early spectra of RXCJ2248-ID3 motivated further rest-UV+optical study with JWST/NIRSpec
by M. W. Topping et al. (2024). This work performed direct metallicity calculations
to show that RXCJ2248-ID3 is one of the most extreme N/O-enhanced (), metal-poor
() galaxies, with high-ionization ([O iii] λ5008/[O ii] λ3728 = 184) and high nebular
density (6.4 × 104 ≤ ne(cm−3) ≤3.1 × 105). They also used spectral energy distribution
(SED) fitting with a constant star formation history to characterize its low stellar
mass (M⋆ ∼ 108 M⊙) and the young-massive star population (∼2 Myr) of RXCJ2248. M.
W. Topping et al. (2024), therefore, suggest that the N/O enrichment may be due
to a short-lived phase that many z > 6 bursty galaxies experience. In this paper,
we build on the work of M. W. Topping et al. (2024) with new, extraordinarily deep
rest-optical JWST/NIRSpec observations of RXCJ2248-ID3 from the GLIMPSE-D Survey,
a Director’s Discretionary Time (DDT) follow-up program described below.\r\n\r\n2.1.
Observations and Reduction\r\nThe work presented here uses both the rest-UV JWST/NIRSpec
archival spectra from JWST PID 2478 (PI Stark) and new rest-optical JWST/NIRSpec
spectra from the GLIMPSE-D Survey, which is an extension of the GLIMPSE Survey.
Properties of RXCJ2248-ID and observation details are presented in Table 1.\r\n\r\nTable
1. Properties of RXCJ2248-ID3\r\n\r\nJWST/NIRSpec Observations\r\nGrating/Filter\t(s)\tPI/PID\r\nG140M/F100LP\t6215\tStark/2478\r\nG235M/F170LP\t1576\tStark/2478\r\nG395M/F290LP\t107,228\tFujimoto
& Naidu/9223\r\nMeasured Properties\r\nProperty\tValue\tReferences\r\nR.A.\t+22:48:45.81\tThis
work\r\nDecl.\t−44:32:14.95\tThis work\r\nz\t6.1025 ± 0.0013\tThis work\r\nμ\t6.8877\tL.
Furtak et al. (2025)\r\nReff (pc)\t\tA. Claeyssens (2025)\r\nM⋆ (M⊙)\t\tA. Claeyssens
(2025)\r\nΣ⋆ (M⊙ pc−2)\t\tA. Claeyssens (2025)\r\nSFRHα (M⊙ yr−1)\t3.2\tThis work,
Section 5.3\r\nSFRSED,1Myr\t4.7\tA. Claeyssens (2025)\r\nSFRSED,10Myr\t4.1\tA. Claeyssens
(2025)\r\nΣSFR (M⊙ yr−1 kpc−2)\t1.34 × 103\tThis work\r\ntage (Myr)\t\tA. Claeyssens
(2025)\r\n12+log(O/H)\t7.753 ± 0.025\tThis work, Section 4.3.1\r\nlog(N/O)\t−0.391
± 0.037\tThis work, Section 4.3.2\r\nNote. Top: JWST/NIRSpec observations of RXCJ2248-ID3,
including archival observations from PID 2478 (PI: Stark) and very deep GLIMPSE-D
observations from PID 9223 (PI: Fujimoto & Naidu). Columns (1)–(3) list the grating/filter,
exposure time, and principle investigator/PID. Bottom: Measured global properties
of RXCJ2248-ID3. The R.A. and decl. are the extraction coordinates for RXCJ2248-ID3.
The redshift was determined from the GLIMPSE-D spectrum emission lines. GLIMPSE
imaging was used to determine the lensing model magnification, μ. Effective radius
of the RXCJ2248-ID3 clump, stellar mass, and current massive star population age
are from the SED modeling of A. Claeyssens (2025), while the SFR was determined
from both the SED fitting and the narrow-component, collisions-corrected Hα flux
(see Section 5.3), all corrected for the lensing factor. The star formation rate
surface density was determined using the SFRHα. The metallicity and relative N/O
abundance were determined using the direct method.\r\n\r\nDownload table as: \r\nASCIITypeset
image\r\n\r\nThe GLIMPSE Survey is a large Cycle 2 JWST program (PID 3293; PIs Atek
& Chisholm) that performed ultradeep NIRCam imaging (∼30.8 mag at 5σ over 0.8–5
μm) in seven broadband and two medium-band filters of the lensing cluster Abell
S1063 (H. Atek et al. 2025). A. Claeyssens (2025) performed size and photometric
measurements of RXCJ2248-ID in the different multiple images. The SED fitting was
performed with the Bayesian Analysis of Galaxies for Physical Inference and Parameter
Estimation (BAGPIPES; A. C. Carnall et al. 2018) code with Binary Population and
Spectral Synthesis (BPASS v2.14, J. J. Eldridge et al. 2017) stellar population
synthesis burst models and cloudy v23.01 photoionization models (M. Chatzikos et
al. 2023; C. M. Gunasekera et al. 2023). Priors were used to be physically consistent
with the source, i.e., high-ionization parameter (), low extinction (Av < 0.5 mag),
low metallicity (Z < 0.4 Z⊙), and bursty star formation (τ = 1 Myr, i.e., close
to a single burst, or τ = 10 Myr). The resulting best fit has a young age ( Myr)
and low stellar mass of but within a compact size of pc such that the stellar mass
surface density is . This value is akin to the highest densities found in globular
clusters, similar to the ones reported for young star clusters and clumps at high
redshift (A. Claeyssens et al. 2025; M. Messa et al. 2026), and broadly consistent
with the conclusions presented in M. W. Topping et al. (2024).\r\n\r\nSubsequent
medium-resolution (R ∼ 1000) spectra of RXCJ2248-ID3 were obtained as part of the
follow-up GLIMPSE-D Survey: JWST DDT Program 9223 (PIs Fujimoto & Naidu) targeting
a Pop III candidate in S. Fujimoto et al. (2025) using NIRSpec Multi-Object Spectroscopy
(MOS) with the G395M grating and F290LP filter. As part of this program, RXCJ2248-ID3
was observed for a total of 13 exposures using a 3-point nod pattern and NRSIRS2
readout, totaling ∼30 hr of integration. The MSA slit positions covering RXCJ2248-ID3
of the three pointings are shown in Figure 1.\r\n\r\nZoom InZoom OutReset image
size\r\nFigure 1. JWST/NIRSpec MSA slits targeting RXCJ2248-ID3 for each of the
three exposures in the GLIMPSE-D program. The two pointings that are closely aligned
(solid purple regions) have the same wavelength coverage, while the pointing offset
to the lower left (dashed region) has somewhat reduced blue coverage. All three
pointings were used in the spectrum coaddition.\r\n\r\nDownload figure:\r\n\r\nStandard
imageHigh-resolution image\r\nWe augment the rest-optical GLIMPSE-D data with archival
rest-far-UV G140M/F100LP and rest-near-UV G235M/F170LP observations from PID 2478
(PI Stark), covering the rest-frame ∼1400–4000 Å range. This program also observed
the G395M/F290LP setting, but we only use the significantly deeper GLIMPSE-D G395M
observations here. Multiple images of RXCJ2248 were identified and observed in program
#2478. M. W. Topping et al. (2024) utilized these data by coadding the spectra of
the individual images. In contrast, only the brightest image (ID3) was observed
in the GLIMPSE-D Survey. To ensure consistency, we therefore restricted our analysis
to the G140M and G235M spectra of ID3 obtained in program #2478. As a result, our
G140M and G235M measurements are not directly comparable to those presented by M.
W. Topping et al. (2024).\r\n\r\nThe data were reduced using v0.9.8 of the msaexp
pipeline (G. Brammer 2022), following the standard routines described in A. de Graaff
et al. (2025), K. E. Heintz et al. (2025), and F. Valentino et al. (2025). Briefly,
level-2 calibrated products from MAST are subject to a series of custom corrections
that account for, e.g., 1/f noise, bar vignetting, and detector bias. We used the
“local” nodded background subtraction. The 2D spectra were drizzled onto a common
wavelength grid and 1D spectra were optimally extracted using a profile model that
accounts for, e.g., the wavelength-dependent PSF and offsets from the nominal position
expected from the catalog. Line centers were measured for the strongest emission
lines in the G395M spectrum (i.e., Hδ, Hγ, [O iii] λ4364, Hβ, [O iii] λλ4960,5008,
He iλ5877, Hα, He iλ7067) and used to determine a redshift of z = 6.1025 ± 0.0013.
Note that the bluest portion of the G395M tends to favor a slightly lower redshift
(i.e., z ∼ 6.1000), while the reddest portion favors a slightly higher redshift
(i.e., z ∼ 6.1034). The three individual 1D extracted spectra were then normalized
to the common continuum flux scale of the first spectrum at rest-wavelengths of
∼6000–62000 Å prior to coadding. Spectral coaddition was performed as a weighted
average using the inverse variance as the weight.\r\n\r\nThe resulting spectrum,
shown in Figure 2, covers an observed wavelength range ∼2.8–5.5 μm, which corresponds
to a rest-optical range of ∼3900–7740 Å. Note that the third pointing (dashed slits
in Figure 1) has reduced wavelength coverage such that the blue end begins at ∼4265.
The deep GLIMPSE-D spectra provide unparalleled signal-to-noise ratio (S/N; >5 at
5100 Å continuum) that enable rest-optical diagnostics typically reserved for nearby
galaxies.\r\n\r\nZoom InZoom OutReset image size\r\nFigure 2. JWST/NIRSpec rest-frame
UV and optical spectra of RXCJ2248-ID3 highlighting the first object known with
simultaneously detected emission from N+, N+2, and N+3 (see, also, M. W. Topping
et al. 2024) and WR features. The second row shows the main emission UV emission-line
detections from the archival G140M/F100LP spectrum, with significant detections
of several high-ionization emission lines, including N iv] λλ1483,1486, C iv λλ1548,1550,
He ii λ1640, O iii] λλ1661,1666, N iii] λ1750, and C iii] λλ1907,1909. The third
row shows the blue end of the optical spectrum, where the left-hand panel shows
the archival G235M/F170LP spectrum, which includes the low-ionization [O ii] λλ3727,3730
doublet. The right-hand panel of the third row and the fourth row shows the extremely
high S/N GLIMPSE-D optical spectrum, enabling detections of several weak features.
Note that some of the important features to this work are highlighted in the zoom
in panels in the top row. In particular, the last panel reveals the most distant
WR detection to date, with the λ4650 WR bump showing emission from N iii λ4642,
indicative of nitrogen enrichment from WN stars. Note that not all of the labeled
lines correspond to line detections.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\n2.2. Emission-line Measurements\r\nIn order to perform a consistent analysis
of our data, we measure emission-line fluxes for both the archival spectra and the
new GLIMPSE-D spectra presented here. We fit neighboring emission lines simultaneously
using Gaussian profiles with the lmfit package (M. Newville et al. 2015) in Python.
Purely nebular lines (i.e., lines without possible stellar contributions or resonant
effects) close in wavelengths were constrained to have the same full width at half-maximum
(FWHM) velocity widths. Additionally, the relative wavelength spacing between lines
was constrained to laboratory values and doublets with constant flux ratios set
by atomic physics were constrained to their theoretical values, with small uncertainty
allowances. The uncertainties on the line fluxes were estimated as the standard
error derived from the least-squares minimization in lmfit, which considers the
uncertainty on the Gaussian profile and linear continuum.\r\n\r\nBroad emission
components are clearly visible at the base of some of the emission lines in the
GLIMPSE-D spectrum of RXCJ2248-ID3. Such broad emission features can be produced
by stellar winds, shocks, or turbulence. Since He iiλ1640 and λ4687 emission lines
can be affected by stellar winds, we fit these features with an unconstrained Gaussian
width. Using the jwst-msa package (A. de Graaff et al. 2024), we deconvolved all
measured FWHMs with the modeled wavelength-dependent line spread function (LSF).
We found the He ii lines to be broadened compared to purely nebular lines. For the
He iiλ 4687 line, the velocity width is 528 ± 100 km s−1, which is more than two
times broader than the narrow nebular Hβ component with vFWHM = 243 ± 25 km s−1.\r\n\r\nThe
strongest rest-optical H (Hγ, Hβ, and Hα) and [O iii] (λ4364, λλ4960,5008) emission
lines have complex profiles with both narrow and broad emission components. Such
broad components may also be present in the rest-UV and fainter rest-optical emission
lines, but none are obvious given the lower S/N of these emission features and/or
underlying continuum. To fit these profiles, we tested three different multicomponent
profile combination fits for the Hα + [N ii] complex. For all three fits, the narrow
Hα and [N ii] λλ6550,6585 lines were fit by Gaussians with a single velocity width,
but the broad component was fit with either: (1) a single Gaussian profile, (2)
two Gaussian profiles, or (3) a single exponential profile. The single broad Gaussian
profile fit had strong residuals near the center of the broad component, so did
not provide a good fit to the observed emission profile. Both the double Gaussian
profile and the exponential profile provided relatively good visual fits, but the
double Gaussian fit had a lower reduced chi-squared ( vs ) and Bayesian inference
criteria (BIC2Gauss = 36 versus (BICexp. = 87), and so was adopted as the better
statistical fit.\r\n\r\nThe right panel of Figure 3 shows the best multicomponent
fit to the Hα + [N ii] complex. Since all kinematically similar lines in the Balmer
emission series arise from the same gas, we expect the Hβ and Hγ profiles to be
well fit by scaling the Hα best fit. Therefore, we constrained the velocity widths
of the Hβ and Hγ emission components to match the narrow + double broad Gaussian
Hα fit, accounting for the wavelength-dependent LSF. We found excellent fit results,
with similarly small reduced-χ2 and BIC values. This means that the H i lines are
well fit by a profile with (1) a strong, narrow (∼250 km s−1) nebular component,
(2) a moderate (∼20% of total flux), broad component (∼670 km s−1), and (3) a weak
(∼10% of total flux), very broad (∼2530 km s−1) component.\r\n\r\nZoom InZoom OutReset
image size\r\nFigure 3. Multicomponent emission-line fits to the GLIMPSE spectrum
of RXCJ2248-ID for Hα λ6565 + [N II] λλ6549,6585 (left panels), Hβ λ4863 + [O III]
λλ4960,5008 (middle panels), and Hγ λ4342 + [O III] λ4364 (right panels). When fit
with single, narrow Gaussian components (e.g., purple and yellow filled Gaussians),
all three line complexes show strong, broad component residual flux. The resulting
best fit to each line is comprised of a single narrow Gaussian plus two broad Gaussians,
where the relevant component velocity widths are tied together: The Hα λ6565 + [N
ii] λλ6549,6585 complex fit provided the velocity width constraints for the H Balmer
line narrow (purple Gaussians) and broad components (blue and green Gaussians) and,
subsequently, the Hβ λ4863 + [O iii] λλ4960,5008 fit constrained the [O iii] narrow
(yellow Gaussian) and broad (orange and red Gaussians) velocity widths that were
then used in the Hγ λ4342 + [O iii] λ4364 fit. Note that additional faint lines
(e.g., He i λ5017) were included in the fit in the middle panel. Careful accounting
for the residual broad flux has a significant impact on the derived nebular reddening,
temperature, metallicity, and N/O abundance.\r\n\r\nDownload figure:\r\n\r\nStandard
imageHigh-resolution image\r\nThe [O iii] λλ4960,5008 doublet lines are also well
fit by a narrow Gaussian plus double Gaussian broad component profile, with the
relative fluxes of each component constrained to the theoretical ratio. While the
narrow-component FWHM was set to the velocity width of the narrow Balmer lines,
convolved with the LSF, we allowed the FWHM of the two broad [O iii] components
to vary freely and found widths of ∼890 km s−1 and ∼2980 km s−1, respectively. The
similarity between the [O iii] and H i velocity widths of the broad components argues
against emission from an AGN directly (where high densities cause collisional de-excitation
of [O iii]) and is more consistent with stellar or AGN driven winds (e.g., Y. I.
Izotov & T. X. Thuan 2008; G. Gräfener & J. S. Vink2015; G. Gräfener et al. 2017;
C. J. Burke et al. 2021). Interestingly, the broad components of the H i lines compose
a larger fraction of their total flux (∼20% and 10%, respectively) than [O iii]
(∼10% and 5%, respectively).\r\n\r\nThe resulting fit to the Hβ + [O iii] λλ4960,5008
complex is shown in the middle panel of Figure 3 to be an excellent fit, with minimal
residuals. The exquisite S/N of the GLIMPSE spectrum also reveals broad wings on
the [O iii] λ4364 profile, as seen in the left panel of Figure 3. Therefore, we
also applied the narrow Gaussian plus double Gaussian broad component profile to
[O iii] λ4364, constraining the velocity widths to the values measured for [O iii]
λλ4960,5008.\r\n\r\nDouble broad components with similar velocity widths (750 and
2500 km s−1, respectively) are seen in the z ∼ 0 extreme emission-line galaxies,
J1044+0353 and J1418+2102, reported in D. A. Berg et al. (2021). However, each broad
component observed in these nearby analogs only accounts for 1%–3% of the total
H i flux. This sort of broad component emission from the Balmer H and [O iii] lines
with widths (1000–2000 km s−1) and fractional fluxes of 1%–2% is commonly found
in spectra of blue compact dwarf galaxies (BCDs; e.g., Y. I. Izotov et al. 2006,
2007). This suggests that bulk motion of the gas is typical in these metal-poor,
bursty environments, but for a larger mass of gas in RXCJ2248-ID3.\r\n\r\nThe sensitive
accounting of broad component emission afforded by the deep GLIMPSE-D spectra is
important because even a small fraction of broad emission around H emission line
can significantly affect the fit to weak lines such as [N ii] λλ6550,6585 (e.g.,
D. A. Berg et al. 2021). In RXCJ2248-ID, the broad components compose a significant
fraction of the total H and [O iii] fluxes, and so are critical to properly measure
not only the [N ii] λ6585 emission but also the [O iii] λ4364, Hβ, [O iii] λλ4960,5008,
and Hα narrow-line fluxes. For this reason, we adopt the narrow-line fluxes from
our best multicomponent fits for the remaining analysis; we reserve further investigation
of the the broad emission for a forthcoming paper.\r\n\r\nAs noted above, the UV
spectra do not have sufficient S/N to decompose narrow and possible broad components.
As a result, density diagnostics and relative abundance ratios determined from UV
line ratios may include contributions from multiple kinematic components. If the
broad components arise from gas with distinct physical conditions, this could introduce
systematic offsets. We test the level of bias possible due to broad component contamination
of narrow-line fluxes by adopting the relative narrow and broad component profiles
of [O iii] λ5008 as a template for collisionally excited lines. The broad component
areas overlap with the narrow profile such that the broad components are responsible
for 8.6% and 2.2% of the narrow-component flux, or 10.8% in total. We use this fraction
to set the upper contamination limit of potential broad components to the UV emission
lines and determine the impact on nebular density, temperature, and abundance calculations
in Section 4.4.\r\n\r\n2.3. Reddening Correction\r\nThe observed Balmer decrement
of the narrow Hα/Hβ lines is FHα/FHβ = 3.48, implying either a moderate amount of
dust is present or collisional enhancement of Hα. This value disagrees with the
results of M. W. Topping et al. (2024), who measured an observed decrement of 2.55
± 0.05 that they found to be consistent with no dust attenuation. Similarly, A.
Crespo Gómez et al. (2025) used high-resolution NIRSpec/G395H data to fit multiple
component Balmer decrements for RXCJ2248-ID3, finding a narrow-component FHα/FHβ
= 2.7 that is consistent with no attenuation, but broad- and very broad-component
decrements of 4.3 and 6.6, respectively, that imply differential extinction. We
too find higher FHα/FHβ ratios for the broad components, but the source of this
increase is not clear; it could indicate higher dust in the broad component gas,
as suggested by A. Crespo Gómez et al. (2025), or result from significant collisional
enhancement of Hα.\r\n\r\nFortunately, the GLIMPSE-D spectrum provides a significant
increase in S/N in the continuum, allowing for more robust fitting of broad components,
including in the Hγ and [O iii] λ4364 and λ5008 lines. Fitting the broad components
directly in the [O iii] lines offers the advantage over previous works that we do
not need to correct for broad component contamination with differential extinction
in our Te calculation. Furthermore, by fitting the broad components in Hγ we were
able to examine the narrow-component Hβ/Hγ ratio, finding a decrement of FHβ/FHγ
= 2.16 that is consistent with very little dust (see Table 2). Note that we do not
consider the Hβ/Hδ ratio here because the Hδ line is not strong enough to robustly
fit the broad components in a consistent manner with the profile fitting of the
Hγ, Hβ, and Hα lines.\r\n\r\nTable 2. Rest UV+Optical Emission-Line Fluxes\r\n\r\nIon+Wavelength\tI(λ)/I(C
iii])\tEW\r\n(Å)\t \t(Å)\r\nN iv] λ1483.33\t42.78 ± 1.61\t6.67\r\nN iv] λ1486.50\t102.0
± 0.82\t15.9\r\nHe iiλ1640.42\t22.46 ± 197\t4.88\r\nO iii] λ1666.15\t85.84 ± 0.59\t18.9\r\nN
iii] λ1750a\t38.59 ± 0.64\t9.18\r\nSi iii] λ1883.00\t5.01 ± 3.25\t1.32\r\nSi iii]
λ1892.03\t8.25 ± 1.98\t2.21\r\nC iii] λ1906.68\t35.11 ± 0.31\t9.65\r\n[C iii] λ1908.73\t64.89
± 0.25\t17.9\r\nIon+Wavelength\tI(λ)/I(Hβ)\tEW\r\n(Å)\t \t(Å)\r\n[O ii] λ3728a\t4.09
± 2.05\t6.22\r\nHγ λ4341.66b\t47.41 ± 3.07\t73.8\r\n[O iii] λ4364.44b\t42.45 ± 1.92\t66.5\r\nHe
i λ4472.73\t8.90 ± 0.39\t27.8\r\nN iii λ4641.94\t1.40 ± 0.20\t4.4\r\nHe ii λ4687.01\t1.33
± 0.29\t4.2\r\n[Ar iv] λ4712.69c\t2.30 ± 0.27\t10.3\r\nHe i λ4714.46c\t1.91 ± 0.19\t3.0\r\n[Ar
iv] λ4741.49\t4.10 ± 0.26\t13.0\r\nHβ λ4862.71b\t100.0 ± 4.4\t356\r\n[O iii] λ4960.29b\t230.5
± 9.0\t877\r\n[O iii] λ5008.24b\t708.9 ± 27.5\t2791\r\nHα λ6564.60b,d\t331.8 ± 14.4\t1755\r\nHα
λ6564.60b,e\t274.1 ± 11.9\t1457\r\n[N ii] λ6585.27\t7.08 ± 0.91\t12.8\r\n[S ii]
λ6718.29\t0.68 ± 0.29\t4.78\r\n[S ii] λ6732.67\t0.81 ± 0.30\t4.74\r\nE(B − V)\t\t⋯\r\nFC
III]\t11.58 ± 0.49\t⋯\r\nb\t6.94 ± 0.15\t⋯\r\nNotes. Reddening-corrected emission-line
intensities of lines used in this analysis from the archival rest-UV and GLIMPSE
rest-optical JWST/NIRSpec spectra for RXCJ2248-ID3. Note that no scaling was performed
between the archival UV and GLIMPSE-D optical pointings (not needed for this work).
Thus, UV fluxes are given relative to the FC III]λλ1907,09 × 100 and optical fluxes
are given relative to FHβ × 100. The last three rows list the dust attenuation derived
using the J. A. Cardelli et al. (1989) reddening law and the rest-frame C iii] λλ1907,09
and Hβ flux in units of 10−18 erg s−1 cm−2. Additionally, the fluxes reported here
are for a single image of RXCJ2248 (ID3), whereas M. W. Topping et al. (2024) report
fluxes for coadded spectra of multiple images. aNote that N iii] λ1750 and [O ii]
λ3728 fluxes are the integrated values for the N iii] λλ1746,1748,1749,1752,1754
quintuplet and [O ii] λλ3727,3730 doublet, respectively. bEmission-line profile
was best fitted with a narrow Gaussian and two broad Gaussian components; only the
corrected narrow-line flux is listed here (see Section 2.2 and Figure 3). c[Ar iv]
λ4713+He iλ4714 is a blended line profile at the observed resolution. Thus, the
[Ar iv] λ4713 is determined by subtracting the He iλ4714 flux, which is predicted
from the He i λ4473 flux. dUncorrected for collisional excitation. eCorrected for
collisional excitation.\r\n\r\nDownload table as: \r\nASCIITypeset image\r\n\r\nThe
reddening due to dust, characterized by E(B − V), was determined by comparing the
observed Balmer decrements with the theoretical Balmer ratios assuming case B and
an extinction law, for which we tested the parameterization from both J. A. Cardelli
et al. (1989) and D. Calzetti et al. (2000). The E(B − V) value for a given Balmer
ratio was determined iteratively until convergence, recomputing the H i theoretical
ratio using the updated electron temperature from the reddening-corrected [O iii]
λ4364/λ5008 flux ratio and density from the reddening-corrected N iv] λ1483/λ1487
flux ratio in each iteration. In this way, the reddening, electron temperature,
and electron density were solved for simultaneously and consistently.\r\n\r\nA greater
enhancement of the observed FHα/FHβ decrement than of the FHβ/FHγ decrement can
arise under high-density conditions, where collisional excitation selectively enhances
the lowest excited level (n = 2; requires lowest energy to excite), leading to higher
Hα flux relative to Hβ and Hγ. To assess whether such an enhancement is physically
plausible, we examined the Cloudy photoionization models (M. Chatzikos et al. 2023;
C. M. Gunasekera et al. 2023) presented in Z. Martinez et al. (2025), which span
a wide range of nebular densities (up to ne = 109 cm−3). For the nebular conditions
determined in this work (i.e., Te, , Z, N/O; see Section 4), densities of ne ∼ 106
cm−3 are needed to produce the observed Hα enhancement while minimally affecting
Hβ and Hγ. Although this density is roughly an order of magnitude higher than the
values measured in M. W. Topping et al. (2024) and in this study (see Section 4.1
and Table 3), it could indicate that the interstellar medium (ISM) contains unresolved
clumps of even higher density than the volume-weighted values probed by the density
diagnostics used in this work. We, therefore, attribute the observed Hα excess to
collisional enhancement.\r\n\r\nTable 3. Nebular Conditions and Abundances for RXCJ2248-ID3\r\n\r\nProperty\tIon.
E\tUsed\tValue\r\n \t(eV)\t \t \r\nTemperatures:\t \t \r\nTe,high meas. (K)\t35.11–54.93\tne(N+3)\t1.97
± 0.03 × 104\r\nTe,int. used (K)\t23.33–34.83\tD. R. Garnett (1992)\t1.81 ± 0.02
× 104\r\nTe,low used (K)\t13.62–35.11\tD. R. Garnett (1992)\t1.68 ± 0.02 × 104\r\nDensities:\t
\t \t \r\nne(N+3) (cm−3)\t47.45–77.47\tTe,high\t\r\nne(Ar+3) (cm−3)\t40.74–59.81\tTe,high\t\r\nne(C+2)
(cm−3)\t24.38–47.89\tTe,int.\t\r\nne(Si+2) (cm−3)\t16.35–33.49\tTe,int.\t\r\nne(S+)
(cm−3)\t10.36–23.33\tTe,low\t\r\nO Abundances:\r\nO+/H+ (×10−5)\t13.62–35.11\tTe,low;
ne(Si+2)\t0.186 ± 0.148\r\nO+2/H+ (×10−5)\t35.11–54.93\tTe,high; ne(Ar+2)\t5.473
± 0.261\r\n \t \t7.753 ± 0.023\r\nIonization Parameters:\r\nlogUint.(O32)\t13.62–54.93\tne
= 104 cm−3\t−1.24 ± 0.23\r\nlogUhigh(N43)\t29.60–77.47\tne = 105 cm−3\t−0.69 ± 0.10\r\nN
Abundances:\r\nN+3/O+2\t47.45–77.47\tTe,high; ne(N+3)\t0.277 ± 0.043\r\nN+2/O+2\t29.60–47.45\tTe,high;
ne(C+2)\t0.145 ± 0.070\r\nN+/O+\t14.53–29.60\tTe,low; ne(Si+2)\t0.367 ± 0.259\r\nICF(N+3/O+2)\t47.45–77.47\tTe,high;
ne(N+3)\t1.542\r\nICF(N+2/O+2)\t29.60–47.45\tTe,high; ne(C+2)\t2.547\r\nICF(N+/O+)\t14.53–29.60\tTe,low;
ne(Si+2)\t0.814\r\nlog(N/O)\t⋯\t⋯\t−0.368 ± 0.062\r\nlog(N/O)\t⋯\t⋯\t−0.434 ± 0.071\r\nlog(N/O)\t⋯\t⋯\t−0.525
± 0.257\r\nlog(N/O)all\t⋯\t⋯\t−0.375 ± 0.056\r\n⋯\t⋯\t−0.390 ± 0.035\r\nC Abundance:\r\nC+2/O+2\t24.38–47.89\tTe,int;
ne(C+2)\t0.107 ± 0.014\r\nICF(C+2/O+2)\t24.38–47.89\tTe,int; ne(C+2)\t1.498\r\nlog(C/O)\t
\t \t−0.795 ± 0.052\r\nSi Abundance:\r\nSi+2/O+2\t16.35–33.49\tTe,low; ne(Si+2)\t0.005
± 0.001\r\nICF(Si+2/O+2)\t16.35–33.49\tTe,low; ne(Si+2)\t3.507\r\nlog(Si/O)\t⋯\t⋯\t−1.781
± 0.157\r\nNote. Ionic and total abundances for RXCJ2248-ID3. Column (1) lists the
property, while Column (2) lists the associated ionization potential energy range
(eV), Column (3) lists the temperature and/or density used in the calculation, and
Column (4) provides the final values. All calculations reported here only used the
narrow components when multicomponent fits were performed. Note that the temperatures
for the intermediate- and low-ionization zones were inferred from Te,high using
the Te–Te relationships of D. R. Garnett (1992). Two ionization parameters are reported
for the O32 and N43 indicators from Z. Martinez et al. (2025). The oxygen abundance
was determined using the archival [O ii] λ3728 detection and the new [O iii] λ5008
fit. N/O was determined using four different ion+ICF (from Z. Martinez et al. 2025)
combinations: (1) optical N+/O+; (2) UV N+2/O+2; (3) UV N+3/O+2; and (4) combination
(N++N+2+N+3)/(O++O+2). C/O and Si/O were determined from the archival UV emission
lines only.\r\n\r\nDownload table as: \r\nASCIITypeset image\r\n\r\nAccordingly,
we adopted the reddening derived from Hγ/Hβ, mag using J. A. Cardelli et al. (1989)
(the D. Calzetti et al. (2000) value is similar at E(B − V) = 0.050 ± 0.1215 mag),
and corrected all emission lines for the resulting (minimal) dust attenuation. We
used the D. Calzetti et al. (2000) reddening law for the rest-UV emission lines
(λ < 3200 Å) and the J. A. Cardelli et al. (1989) reddening law for the rest-optical
emission lines (λ > 3200 Å). After applying the reddening correction, the Hα/Hβ
ratio still shows a collisional excess of 0.204 above the theoretical value; we
correct for this excess and report a final FHα = 1.985 × 10−17 erg s−1 cm−2.\r\n\r\nThe
adopted reddening and dereddened line intensities are listed in Table 2 for all
line fluxes used in this work. Note that rest-UV and rest-optical lines should not
be compared or combined in line ratios. Since the rest-UV and rest-optical spectra
were obtained during different observing runs with distinct pointings and strategies,
we report the UV lines relative to FCIII]λλ1907,1909 × 100 and the optical lines
relative to FHβ × 100, without applying any relative scalings between the two datasets.\r\n\r\n3.
Wolf Rayet Stars at z = 6.1\r\nThe WR stage of massive star evolution is an important,
short-lived phase that can have significant effects on the chemical composition
of the local ISM. We provide a brief overview here (see, e.g., P. A. Crowther 2007,
for a more thorough review). WR stars are massive stars that have entered the core
He-burning phase and have lost their outer envelope either via strong stellar winds
or due to binarity effects (i.e., stripping via Roche Lobe overflow or mergers).
The first phase of WR stars occurs when the outer H layer has been ejected, revealing
the H core-burning products such that their spectra are characteristically He and
N rich but are H-poor. Such stars are known as nitrogen-type WR, or WN, stars, and
are often identified by strong N iii, N iv, and N v emission lines, especially the
broad optical “blue bump” near λ4650. The blue bump is a complex of features, including
N iii λλ4634,4642, C iii λ4649,4667, Fe iii λ4660, and He ii λ4687. Subsequently,
stars that are massive enough for core He-burning and for their winds to remove
their outer He envelope and expose the produced C enter the WR carbon (WC) phase.
WC stars also have strong, broad He ii emission and strong C and O emission, such
that they are identified by the optical WR C iv λλ5803,5814 doublet (the “red bump”).
As a result, the typically very strong winds of the WR phase can produce significant
N enrichment during the WN phase and drive strong C ejection during the WC phase.
After the WC phase, a WR-oxygen phase may ensue, but we forgo discussion of this
phase here.\r\n\r\nThe rest-frame UV and optical spectra shown in Figure 2 can be
used to characterize the WR nature of the stellar population in RXCJ2248-ID3. Both
the UV and optical He ii emission features are kinematically broadened compared
to the narrow nebular emission features in RXCJ2248-ID3, indicative of WR or VMS
winds. F. Martins et al. (2023, 2025) have shown that young star-forming regions
dominated by VMSs can be distinguished from WR stars using the morphology of the
blue and red bumps. In particular, VMSs produce blue bumps with He ii λ4687 emission
but little to no N iii emission and red bumps with narrow C iv λλ5803,5814 emission.
Thus, strong detections of N iii in the blue bump favor a WN interpretation (e.g.,
F. Martins et al. 2023; D. A. Berg et al. 2024; T. E. Rivera-Thorsen et al. 2024).\r\n\r\nThe
upper right-hand panel of Figure 2 highlights the blue bump spectral regime, showing
weak, broad He ii and N iii λ4642 in RXCJ2248-ID3, both of which are characteristic
of metal-poor WN stars. Just redward of the N iii λ4642 line in the blue bump (but
blueward of [Fe iii]), a second less prominent emission feature is seen, but it
is difficult to determine whether this is due to C iii or O ii emission, or both.
Furthermore, the red C iv bump is not detected, suggesting little to no contributions
from WC stars or VMSs in the spectrum. Thus, we only significantly detect the blue
WR bump, suggesting that WN stars are likely present.\r\n\r\n4. Nebular Properties\r\nUsing
the updated narrow-component emission-line fits presented in Section 2.2, we determined
the nebular properties of RXCJ2248-ID3. Following D. A. Berg et al. (2021), we adopt
the four-zone ionization model to account for the high-ionization emission observed.
In this model, the ionization potential energy ranges of N+, S+2, O+2, and He+2
define the low-, intermediate-, high-, and very high-ionization zones, respectively.
For all calculations, we use the PyNeb package in Python with the atomic data adopted
in D. A. Berg et al. (2019), which includes a six-level atom model for oxygen in
order to utilize the UV O iii] λ1666 line. Below, we determine temperatures and
densities, although Te(O+2) and ne(N+3) were codetermined during the iterative reddening
calculation (see Section 2.3) in Section 4.1, ionization parameters in Section 4.2,
and abundances in Section 4.3.\r\n\r\nWe note that the UV spectra do not have sufficient
S/N to decompose narrow and broad components following the same method as the optical
lines. As a result, density diagnostics and abundances determined from UV lines
may include contributions from multiple kinematic components, while optical temperatures,
densities, and abundances are derived from narrow components alone. If the broad
component arises from gas with distinct physical conditions, this could introduce
systematic offsets. For this reason, we examine the potential impact of UV broad
components in Section 4.4.\r\n\r\n4.1. Temperature and Density\r\nOne of the unique
characteristics of RXCJ2248-ID3 is its large number of density-sensitive emission-line
ratios. M. W. Topping et al. (2024) previously reported densities from the three
UV line ratios of Si iii] λ1883/λ1892, characterizing the intermediate-ionization
zone, C iii] λ1907/λ1909, characterizing the intermediate- to high-ionization zone,
and N iv] λ1483/λ1486, characterizing the high- to very high-ionization zone. The
new high-S/N optical spectra enables us to measure, for the first time, densities
from the low-ionization [S ii] λ6717/6731 ratio and the high- to very high-ionization
[Ar iv] λ4713/λ4741 ratio.\r\n\r\nWe use our narrow-component dereddened flux measurements
to compute densities for all five line ratios and the high-ionization zone temperature
from the [O iii] λ4364/λ5008 ratio. The high-ionization zones Te(O+2) and ne(N+3)
were simultaneously determined during the iterative reddening calculation in Section
2.3 to account for the sensitivities of both diagnostics. If the low density limit
was assumed instead (ne ≲ 102 cm−3), as is common practice at low-redshift, the
observed [O iii] λ4364/λ5008 flux ratio would lead to unphysical temperatures (i.e.,
above the limit set by H cooling of ∼2.5 × 104 K). Thus, a physical and robust solution
requires high densities to properly account for the reduced λ5008 flux due to collisional
de-excitation. Furthermore, Z. Martinez et al. (2025) recently showed that densities
derived from both optical and UV diagnostics underpredict the true volume-averaged
density in multiphase, high-density systems, with more severe underprediction from
the optical diagnostics. Therefore, it is necessary to use UV density diagnostics
in high-density environments, though the true density will still be underestimated
in multiphase gas (see, e.g., Figure 11 of Z. Martinez et al. 2025).\r\n\r\nFor
the high-ionization zone, we found a Te(O+2) = 1.97 ±0.03 × 104 K and ne(N+3) cm−3,
which is consistent with the density of ne(N+3) cm−3 reported by M. W. Topping et
al. (2024), but lower than their temperature of 2.46 ± 0.26 × 104 K due to our broad
component fits of both [O iii] λ4364 and λ5008. Adopting our Te(O+2) as the high-ionization
temperature (Te,high), we then applied the Te–Te relations of D. R. Garnett (1992)
to estimate the intermediate-ionization temperature (Te,int.) and low-ionization
temperature (Te,low).\r\n\r\nThe determined temperatures were used for the subsequent
density calculations in their respective ionization zones. Note that the [Ar iv]
λ4713 and He i λ4714 lines are blended in the G395M grating. Therefore, we corrected
the [Ar iv] λ4713 flux for the He i λ4714 contribution, predicting the He i λ4714
flux from the measured He i λ4473 flux and the theoretical He i λ4714/λ4473 ratio
(∼0.21 for the conditions in RXCJ2248-ID). The resulting densities, all of which
fall within their respective diagnostic ranges, and temperatures are reported in
Table 2.\r\n\r\nRemarkably, RXCJ2248-ID3 is one of few galaxies, and the only galaxy
yet at high redshifts, to have significant (>3σ) electron density measurements from
five different ions that span a large ionization range (∼10–77 eV). Furthermore,
the densities in RXCJ2248-ID3 appear to be organized into an interesting nebular
stratification. The UV emission lines trace the densest gas, with ne(N+3) = 2.65
× 105 cm−3 in the highest-ionization gas, followed by ne(C+2) = 7.94 × 104 cm−3
and ne(Si+2) = 4.77 × 104 cm−3. In contrast, the optical high-ionization lines are
emitted from regions of lower densities: the optical [Ar iv] diagnostic has an overlapping
ionization energy range with the UV N iv] diagnostic but a density that is an order
of magnitude lower.\r\n\r\nThere are two possible interpretations of the measured
array of densities. First, since the UV lines also have higher excitation energies,
they could originate preferentially from hotter, denser clumps. This would imply
a strongly inhomogeneous ISM, in which compact, high-pressure structures dominate
the UV line emission while somewhat more diffuse gas produces much of the optical
emission. Alternatively, the multiphase ISM may span a smaller dynamic range of
densities than we measure due to the suppression of the optical diagnostics. Z.
Martinez et al. (2025) showed that for an ISM with a mix of low- (e.g., 103 cm−3)
and high-density gas (e.g., 105 cm−3) that has a true volumetric density that is
somewhere in between, the low-ionization optical diagnostics will always be significantly
biased low, close to the low-density gas value, until the fraction of high-density
gas is very high (e.g., >95%). This effect occurs when ne-diagnostic line ratios
have low critical densities (e.g., ne,crit([S ii])≈2 × 103–5 × 103 cm−3), such that
emission from the high-density gas is collisionally suppressed beyond detection.
The magnitude of this effect decreases with increasing critical density such that
[S ii] is significantly affected, [Ar iv] is moderately affected (ne,crit ≈ 2 ×
104–2 × 105 cm−3), and the UV Si iii], C iii], and N iv] (ne,crit ≈ 5 × 104–5 ×
1010 cm−3) are minimally affected, albeit still biased low. In this scenario, there
would still be density stratification, but with smaller differences.\r\n\r\nAll
together, the nebular diagnostics in RXCJ2248-ID3 support a picture of a multiphase
nebula with density and temperature stratification, likely reflecting a clumpy ISM
shaped by the feedback and local radiation field variations of bursty star formation
(see, also, N. Choustikov et al. 2025; Y. Harikane et al. 2025b; M. Usui et al.
2025). This picture is also consistent with the density stratification that has
been reported for dwarf galaxies both near and far (e.g., B. L. James et al. 2016;
D. A. Berg et al. 2021; M. Mingozzi et al. 2022; X. Ji et al. 2024; M. W. Topping
et al. 2024), but with typical densities increasing with redshift (e.g., Y. Isobe
et al. 2023; Abdurro’uf et al. 2024; Z. Martinez et al. 2025; M. W. Topping et al.
2025a).\r\n\r\n4.2. Ionization Parameter\r\nThe ionization parameter of RXCJ2248-ID3,
, determined using the typical O32 = Iλ5008/Iλ3728 diagnostic is reported in M.
W. Topping et al. (2024) to be in the high range of to −1. We recompute the ionization
parameter for RXCJ2248-ID3 using the O32 and N43 = Iλλ1483,1486/Iλ1750 diagnostics
from Z. Martinez et al. (2025) that are calibrated for densities in the 102 ≤ ne(cm−3)
≤ 106 range. We estimate a using O32, which is consistent with the value reported
by M. W. Topping et al. (2024), and using N43. Note, however, that the O32 diagnostic
is very sensitive to the assumed density (Z. Martinez et al. 2025), making this
value highly uncertain in dense gas. For example, densities of ne = 103–105 cm−3
would lead to a range of to −2.04, respectively.\r\n\r\n4.3. Abundances\r\nHere,
we present direct-method abundances of oxygen-to-hydrogen (O/H) (Section 4.3.1),
N/O (Section 4.3.2), carbon-to-oxygen (C/O) (Section 4.3.3), and silicon-to-oxygen
(Si/O) (Section 4.3.4) for RXCJ2248-ID3 using narrow-line flux ratios and the measured
temperatures and densities presented in Section 4.1. Nearly all of the optical lines
used in this work have sufficient S/N to simultaneously constrain broad and narrow
emission components, but there are a few exceptions, all of which are low-ionization
lines. The [O ii] λ3728 line was not covered by the GLIMPSE-D spectrum and so lacks
the S/N to fit broad components. Both [N ii] λ6585 and [S ii] λλ6718,6733 are covered
in the high-S/N GLIMPSE-D spectrum but are either blended with stronger features
or too weak to fit broad components. On the other hand, the [O ii] and [S ii] lines
have low critical densities around ne,crit ∼ 103 cm−3 such that any moderate to
high-density broad components are likely collisionally de-excited away. Their narrow-component
fluxes could also be significantly reduced by collisional de-excitation; however,
the missing [O ii] emission is likely small in the absolute sense for such a high-ionization
object. Emission from [N ii] is less likely to be collisionally de-excited (ne,crit
∼ 105 cm−3), so a hidden broad component could lead to an overestimate of the N/O
abundance, but this effect would be somewhat countered by the underestimated [O
ii] flux. In the end, the consistency of N/O derived independently from UV and optical
tracers in Section 4.3.2 below suggests that these effects do not significantly
impact our results.\r\n\r\nTo calculate the total or relative abundance of an element,
we determine and sum the individual observed ions and then apply an ionization correction
factor to account for unseen prominent ionization states. The abundance of an individual
ionic species, Xi, relative to hydrogen is determined as\r\n\r\nwhere jλ(i) is the
emissivity determined for the appropriate ionization zone temperature and density.
Given the tendency of the optical density diagnostics to severely underestimate
the density in high-density environments, we instead adopt the UV-derived densities.
Note that the abundances presented below have not been corrected for the fraction
of atoms embedded in dust. However, the level of depletion onto dust grains is expected
to be small for the low metallicity of RXCJ2248-ID3 (e.g., A. Rémy-Ruyer et al.
2014; F. Galliano et al. 2018; J. Roman-Duval et al. 2022). Y. Isobe et al. (2026)
also infer negligible dust depletion for RXCJ2248-ID3 based on the high value of
Si/O that that they determine, but this is inconsistent with the value we determine
below. Details of elemental abundance determinations are given below.\r\n\r\n4.3.1.
Oxygen Abundance\r\nWe determine the total O/H abundance as the sum of the O+/H+
and O+2/H+ ionic abundances, determined from the [O ii] λ3728 and [O iii] λλ4960,5008
optical emission lines. We observe no strong O0 or O+3 emission, indicating that
contributions from other ions are negligible. The resulting ionic and total oxygen
abundances are presented in Table 2. Similar to M. J. Hayes et al. (2025) and Z.
Martinez et al. (2025), we find that one of the most significant effects of accounting
for high densities is the resulting decrease in electron temperature and subsequent
increase in oxygen abundance (see, also, H. Katz et al. 2023). In our work, this
results both from accounting for the missing [O iii] λ5008 flux due to collisional
de-excitation and from correcting the narrow emission for broad emission components
at their base. M. W. Topping et al. (2024) also incorporated the high densities
seen in RXCJ2248-ID3 but did not have the S/N to fit the broad emission components
in both [O iii] λ5008 and λ4364. As a result, we measure an oxygen abundance of
. Note that if unresolved high-density clumps (ne ≳ 105 cm−3) are present (as suggested
in, e.g., Section 2.3), it could introduce additional uncertainty by biasing the
luminosity-weighted [O iii] λ4364/λ5008 ratio to higher densities, which would drive
the derived Te higher and O/H abundance lower. However, Z. Martinez et al. (2025,
see Figure 11), showed that the use of high-critical density UV density diagnostics
largely mitigate this effect in a density stratified medium.\r\n\r\n4.3.2. Relative
N/O Abundance\r\nThe extraordinary simultaneous detections of [N ii] λ6585, N iii]
λ1750, and N iv] λλ1483,1487 enable multiple determinations of the N/O abundance.
Therefore, we calculate N/O abundances using four different ionic methods\r\n\r\n\r\n\r\n\r\nwhere
[O ii] λ3728 is used for the N+/O+ determination, O iii] λ1666 is used for the N+2/O+2
and N+3/O+2 calculations, and X(N+i) and X(O+i) are the N and O ionization fractions,
respectively. We use the density-dependent ICFs from Z. Martinez et al. (2025),
who provide prescriptions for densities of ne = 102, 103, 104, 105, and 106 cm−3.
We, therefore, round our density measurements to the nearest order of magnitude
and use the intermediate-ionization for the N+/O+ ICF and the high-ionization for
the N+2/O+2 and N+3/O+2 ICFs. The resulting N ICFs and N/O abundances are reported
in Table 3.\r\n\r\nThe four N/O determinations of RXCJ2248-ID3 are in close agreement,
far above the expected value for its metallicity. Visually, this is shown in the
upper left-hand panel of Figure 4, which plots the relative N/O versus O/H abundance
with RXCJ2248-ID3 marked by purple diamonds. The traditional N/O–O/H trend has been
established by many z ∼ 0 studies of H ii regions and galaxies (gray points: C.
Esteban et al. 2002, 2009, 2014; L. S. Pilyugin & T. X. Thuan 2005; L. van Zee &
M. Haynes 2006; J. García-Rojas & C. Esteban 2007; Á. R. López-Sánchez et al. 2007;
D. A. Berg et al. 2012, 2016,2019, 2020). The empirical trend is a bimodal relationship,
with a flat trend due to primary (or metallicity-independent) N production at low
metallicities () and an increasing N/O trend with O/H as secondary (or metallicity-dependent)
N production becomes increasingly important at higher metallicities (). As a visual
guide, the primary N/O plateau from D. A. Berg et al. (2019, dashed purple line)
is shown and the empirical stellar curve from D. C. Nicholls et al. (2017, solid
green line) is shown as an example of the full primary and secondary curve.\r\n\r\nZoom
InZoom OutReset image size\r\nFigure 4. Relative C and N abundance trends versus
metallicity. Nitrogen to oxygen ratio versus oxygen abundance for star-forming galaxies
is plotted in the left panels, while C/O ratio versus oxygen abundance is plotted
in the middle panels, and carbon to nitrogen abundance versus oxygen abundance is
plotted in the right panels. Top row: RXCJ2248-ID3 is shown relative to the observed
z ∼ 0 trend and other high-z galaxies. The abundances for RXCJ2248-ID3 are shown
as purple diamonds, where multiple N/O points show the measurements for each ionic
N/O calculation method. For comparison, we also plot the abundances derived for
RXCJ2248-ID3 by M. W. Topping et al. (2024) as turquoise squares. The typical bimodal
N/O trend is characterized by local dwarf (gray diamonds; L. van Zee & M. Haynes
2006; D. A. Berg et al. 2012, 2016, 2019) and spiral galaxy (gray circles; C. Esteban
et al. 2002, 2009, 2014; L. S. Pilyugin & T. X. Thuan 2005; J. García-Rojas & C.
Esteban 2007; Á. R. López-Sánchez et al. 2007; D. A. Berg et al. 2020) H ii region
measurements. The primary N/O plateau from D. A. Berg et al. (2019) is shown as
a dashed purple line, while the solid green line is the empirical stellar curve
from D. C. Nicholls et al. (2017). Additional C/O literature measurements for dwarf
galaxies are from M. A. Peña-Guerrero et al. (2017) and P. Senchyna et al. (2017).
Abundances for z > 2 galaxies from Z. Martinez et al. (2025) are plotted as blue
plus signs for galaxies with UV N+2/O+2 derived abundances and pentagons for optical
N+/O+ derived abundances. Bottom row: The same observed samples are shown as the
top row, but with the z ∼ 0 sample represented by the shaded gray regions. The observed
abundances of RXCJ2248-ID3 are compared to updated dual-burst chemical evolution
models of C. Kobayashi & A. Ferrara (2024, string of circles), color coded by age
since onset of the second burst. The models have been modified to reproduce both
the enhanced N/O and relatively deficient C/O observed for RXCJ2248-ID3, which requires
enrichment from WN but very little WC enrichment, as expected at low metallicities.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\nFor comparison, we plot the
high-quality high-redshift N/O measurements that were calculated in a consistent
manner as the present work (with direct-method Te and ne determinations and ne-dependent
ICFs) by Z. Martinez et al. (2025). N/O abundances determined using N+2/O+2 are
plotted as blue + symbols, while N+/O+ determinations are plotted as blue pentagons.
Of these galaxies, the closest comparison to RXCJ2248-ID3 is CEERS-1019 (see, also,
R. Marques-Chaves et al. 2024), while only GDS 3073 and GN-z11 have higher relative
N/O abundances and only GDS 3073 is more enhanced in N/O for its O/H abundance.\r\n\r\nWe
find that all four ionic methods produce consistently high N/O values within their
uncertainties, with a weighted mean of . This is an important result because RXCJ2248-ID3
is the first galaxy to have consistently enhanced N/O abundances measured from both
the rest-frame UV high-ionization and the optical low-ionization emission lines.
Furthermore, measuring consistent N/O values from three different ionic methods
strengthens our confidence in the robustness of the N/O measurement, although uniform
N/O across the ionization structure of the nebula is not a given in a stratified
medium. While there is strong evidence for a stratified, or perhaps very clumpy,
density structure in RXCJ2248-ID, the N/O abundance appears to be well mixed.\r\n\r\n4.3.3.
Relative C/O Abundance\r\nMeasuring the C/O abundance provides a crucial comparative
baseline for interpreting the origin of elevated N/O in RXCJ2248-ID3. Similar to
N, C has a pseudosecondary17 production pathway, but the dominant nucleosynthetic
sources and timescales differ for C and N. Briefly, both C and O are primarily produced
in massive stars (>8 M⊙) on relatively short timescales such that the C/O ratio
is a relatively stable tracer of massive star yields, although some C is produced
via low- to intermediate-mass AGB stars (∼1.5–3 M⊙). In contrast, some N is produced
by massive stars (e.g., through rotational mixing and WR winds) but most N comes
from intermediate-mass AGB stars (∼4–8 M⊙), which release N on longer timescales
(∼200 Myr). Therefore, N/O and C/O together serve as diagnostics of the recent star
formation history, constraining the recent enrichment mechanisms of galaxies (e.g.,
D. R. Garnett 1990; R. B. C. Henry et al. 2000; C. Chiappini et al. 2003; E. Pérez-Montero
& T. Contini 2009; D. A. Berg et al. 2019; E. Pérez-Montero et al. 2021).\r\n\r\nRelative
C/O abundances are typically determined using the C iii] λλ1907,1909/O iii] λ1666
ratio to calculate C+2/O+2 and assuming that C/O ≈ C+2/O+2. This method is sometimes
used alone owing to the fact that (1) C+2 and O+2 have somewhat similar ionization
potentials (24.38 and 35.12 eV, respectively), (2) the upper levels of the λ1666
and λλ1907,1909 transitions have similar excitation potentials (∼6.5 and ∼7.5 eV,
respectively), and (3) the integrated fluxes of λ1666 and λλ1907,1909 are not sensitive
to collisional de-excitation for the densities measured here. However, for the high-ionization
nebulae in RXCJ2248-ID3, it is important to account for contributions from the C+3
species and any unseen species. We note that the C iv λλ1548,1550 doublet is clearly
observed in the rest-UV spectrum of RXCJ2248-ID3, but these lines are resonant and
can be affected by the C iv stellar wind feature and ISM absorption, and so determining
the intrinsic flux and subsequent C+3 abundance is challenging. Instead, we use
an ICF determined from the photoionization models presented in Z. Martinez et al.
(2025) such that\r\n\r\nWe used the and a density of ne(C+2) ∼ 105 cm−3 to determine
the C ICF. The resulting C ICF and C/O abundance are reported in Table 3.\r\n\r\nThe
C/O and C/N abundances for RXCJ2248-ID3 are plotted in the upper middle and right-hand
panels of Figure 4. Empirical trends of C/N at z ∼ 0 are found to be flat, albeit
with significant scatter (see shading in Figure 4), suggesting that the dominant
nucleosynthetic mechanisms of C are similar to those of N (e.g., D. R. Garnett et
al. 1999; C. Esteban et al. 2014; D. A. Berg et al. 2016, 2019). However, while
the production of both C and N appear to be metallicity-dependent, the scatter in
their trend is consistent with differing production timescales due to stars of different
masses. Thus, the variations observed in CNO abundance patterns of high-redshift
galaxies may be the result of taking a snapshot of many galaxies at different times
since their most recent onset of star formation.\r\n\r\nRXCJ2248-ID3 appears to
have a similar CNO abundance pattern to other high-redshift N emitters, characterized
by enhanced N/O but relatively deficient C/O such that their C/N is very deficient
compared to the expectations from low-redshift trends. This suggests that these
high-redshift N-emitting galaxies are enhanced in N relative to both O and C. If
massive stars in the WN phase are present, they will have recently produced 14N
at the expense of 12C through the CNO cycle, meaning C used as a catalyst in the
cycle initiation will have been consumed as N is removed during the bottleneck step
via dredged up, preventing the return of C at cycle completion. Thus, C/N-deficiency
is consistent with a recent, intense episode of N enrichment and C consumption from
WN stars. Conversely, if both N/O and C/O were elevated in tandem, it could point
to broader enrichment by massive stars, such as enrichment from both WN and WC stars,
whose contributions increase at higher metallicities.\r\n\r\n4.3.4. Relative Si/O
Abundance\r\nDetecting Si iii] λλ1883,1892 in RXCJ2248-ID3 enables the rare opportunity
to measure the silicon-to-oxygen (Si/O) abundance in a z > 5 galaxy (see, also,
Y. Isobe et al. 2026, for Si/O in GN-z11). Silicon abundances are important for
multiple reasons. Silicon is highly refractory, making the Si/O ratio a sensitive
probe of dust depletion. Additionally, Si probes different channels of chemical
enrichment than CNO elements, as it is primarily an α-element produced by CCSNe,
but Type Ia SNe, AGB stars, and even pair-instability SNe are all expected to contribute
to the total Si abundance. For RXCJ2248-ID3 we determine the Si/O abundance using
the observed Si iii] λλ1883,1892/O iii] λ1666 ratio to calculate Si+2/O+2. Because
Si+2 and O+2 have rather different ionization potentials (16.3 eV versus 35.1 eV,
respectively), a Si ICF is required to convert Si+2/O+2 to total Si/O via\r\n\r\nSi
ICFs have been reported previously (e.g., D. R. Garnett et al. 1995), but none account
for the high-density conditions observed in RXCJ2248-ID3. Therefore, we determined
a Si ICF = 3.507 using the photoionization models presented in Z. Martinez et al.
(2025) using the and a density of ne(Si+2) ∼ 104 cm−3. Reported in Table 3, the
resulting (Si/O) = −1.781 ± 0.157 abundance is typical of metal-poor dwarf galaxies
(e.g., D. R. Garnett et al. 1995; Y. I. Izotov & T. X. Thuan 1999), consistent with
normal massive star production and low dust depletion.\r\n\r\n4.4. Potential Impact
of UV Broad Components\r\nThe exceptionally high S/N of the rest-optical GLIMPSE-D
spectrum allows for broad emission component fits that the rest-UV spectrum does
not. In Section 2.2, we found the broad emission component contribution to the narrow
[O iii] λ5008 flux to be 10.8%. To examine the possible effects such contamination
has on calculations of nebular conditions and abundances, we adopt 10.8% as the
contamination upper limit to the UV emission lines. We first consider the impact
on the UV density determinations, where we allow the broad components of the UV
density-sensitive emission-line ratios to have densities ranging from 102–106 cm−3.
After subtracting the potential broad component contribution, the revised densities
change up to Δne(Si+2), Δne(C+2), and Δne(N+3) over the range of broad component
densities considered. These values are within the reported uncertainties in Table
3, with the exception of the ∼1.2σ deviation for Δne of C+2.\r\n\r\nNext, we tested
the subsequent impact of UV densities that have been revised for possible broad
components on the properties determined from rest-optical emission lines: Te(O+2),
O/H, and N/O. For the range of Δne(N+3) above, the resulting K, which is within
1σ–2σ of the reported value in Table 3. Similarly, the impact of the revised densities
and temperatures on the oxygen abundance, dex, is also within 1σ–2σ. The impact
is even smaller for the nitrogen abundance, with dex being much smaller than the
N/O uncertainty.\r\n\r\nRelative UV abundances are impacted by changes in both the
nebular conditions and the relevant abundance emission-line ratio. However, the
resulting abundance deviations are small and within the original uncertainties:
dex, dex, and dex. Thus, we conclude that while considering the impacts of hidden
broad component contributions to the measured UV fluxes is important, the potential
biases do not affect the main results or conclusions of this work.\r\n\r\n5. A Short
Window of Intense WR Nitrogen Enrichment\r\nWe have presented evidence for WN stars
in RXCJ2248-ID3 in two forms: first, the rest-frame optical WR blue bump discussed
in Section 3 and shown in Figure 2; and second, a qualitative comparison of the
CNO abundances to patterns expected for WR stars in Section 4.3 and Figure 4. Below,
we examine the plausibility and impact of these WN stars by comparing RXCJ2248-ID3
to expected trends for WR stars with metallicity (Section 5.1), testing whether
stellar yields can reproduce the observed CNO abundance pattern (Section 5.2) and
assessing whether RXCJ2248-ID3’s stellar population can produce its inferred mass
of ionized N (Section 5.3). Together, these lines of investigation suggest that
the enhanced N/O and suppressed C/O in RXCJ2248-ID3 represent a short-lived enrichment
phase, unique to metal-poor, highly star-forming galaxies in the early Universe
(Section 5.4).\r\n\r\n5.1. WN Stars: The Dominant WR Phase at Low Metallicity\r\nTo
date, no individual resolved WR stars have been directly observed at metallicities
as low as RXCJ2248-ID3 (Z ∼ 0.1Z⊙). This is due, in part, to the lack of sufficiently
close (D ≲ 1 Mpc for the young, crowded clusters hosting WR stars), metal-poor,
star-forming galaxies (see C. Kehrig et al. 2013 for the closest metal-poor WR galaxy),
but a scarcity of WR stars in metal-poor environments is also expected because mass
loss through stellar winds scales with metallicity. We show the trend of the number
of WC/WN stars as a function of metallicity in Figure 5. The observed number of
WC/WN stars in M31 (∼175% Z⊙), the Milky Way (MW; Z⊙), M33 (∼40%–110% Z⊙), the Large
Magellanic Cloud (LMC; ∼40% Z⊙), and the Small Magellanic Cloud (SMC; ∼20% Z⊙) suggest
that the number of the WN/WC number ratio increases with decreasing metallicity
(e.g., G. Meynet & A. Maeder 2005; P. A. Crowther 2007; P. Massey et al. 2015; K.
Neugent & P. Massey 2019). This is because weaker metal line-driven winds, rotation,
or binary effects in metal-poor stars may be able to expose their nitrogen-rich
layers and initiate the WN phase but be insufficient to strip the stellar He atmosphere
and reveal the carbon-rich core to initiate the WC phase. Thus, if WR stars form
at Z ∼ 10% Z⊙, they are expected to be overwhelmingly WN-type. Additionally, A.
A. C. Sander et al. (2026) recently discovered a new class of WN–WO stars that point
to a low-metallicity WR evolutionary channel in which stars pass directly from the
WN to WO phase, potentially explaining spectra that show evidence for WN-like enrichment
and hard ionizing radiation without clear WC signatures.\r\n\r\nZoom InZoom OutReset
image size\r\nFigure 5. Observed and theoretical ratios of WC/WN star numbers as
a function of metallicity. Observed values for the SMC, LMC, MW, and M31 were compiled
by K. Neugent & P. Massey (2019), while newer values for M33 come from K. F. Neugent
& P. Massey (2023). For comparison, we also plot the trend presented in P. Massey
et al. (2017) for BPASS v2.0 binary stellar population synthesis burst models for
12+log(O/H) > 8 (solid line green line), which we extrapolate to lower metallicities
(dashed line). Enrichment from WR stars was used to explain the CNO abundances in
GN-z11 by C. Kobayashi & A. Ferrara (2024). We note the metallicity for GN-z11 determined
by Z. Martinez et al. (2025) is consistent with a WC/WN ratio of ∼0.1–0.2 and the
metallicity for RXCJ2248-ID3 from the current work, which predicts a much lower
WC/WN ratio of ∼0.03–0.10. Therefore, very little carbon enrichment from WC stars
is expected for RXCJ2248-ID3.\r\n\r\nDownload figure:\r\n\r\nStandard imageHigh-resolution
image\r\nThe spectral features of RXCJ2248-ID3 support the picture of WN star feedback
at low metallicity. As shown in Figure 2, the He ii emission is moderately broadened,
the N iii λ4642 line in the blue bump is prominent, and there is no evidence for
the red bump C iv feature, all consistent with the presence of WN stars at low metallicity.
The weakness of the He ii emission in terms of both flux and velocity width is expected
for the low-metallicity environment of RXCJ2248-ID3 (∼10% Z⊙) due to reduced wind
velocities and mass-loss rates (e.g., A. A. C. Sander et al. 2020). Similarly weak
WN features have also been reported in the nearby metal-poor galaxy SBS 0335-052
(Y. I. Izotov et al. 2006) and, at cosmic noon, the z ∼ 2.37 lensed galaxy the Sunburst
Arc (T. E. Rivera-Thorsen et al. 2024) and the z ∼ 2.22 M4327 galaxy (M. Curti et
al. 2025b).\r\n\r\nWe plot the WR blue bump profile of RXCJ2248-ID3 relative to
the Sunburst Arc and M4327 in Figure 6. For ease of comparison, we convolve the
Sunburst Arc R ∼ 2700 JWST/NIRSpec G140H spectrum to the R ∼ 1000 resolution of
the RXCJ2248-ID3 spectrum. For M4327, we retrieved the G140M spectrum obtained as
part of the Measuring Abundance at High Redshift with the Te Approach Survey (MARTA;
E. Cataldi et al. 2025) from the Dawn JWST Archive (DJA; K. E. Heintz et al. 2024;
A. de Graaff et al. 2025). Both the Sunburst Arc and M4327 spectra were scaled to
similar He ii strengths as RXCJ2248-ID3. These spectra immediately reveal similar
profiles, but with three distinct differences: (1) RXCJ2248-ID3 exhibits higher
gas ionization, as evidenced by the strong [Ar iv] λλ4713,4741 emission; (2) the
He ii stellar wind feature is significantly broader in both the Sunburst Arc (FWHM
= 1370 km s−1) and M4327 (FWHM = 1460 km s−1) than RXCJ2248-ID3 (FWHM = 530 km s−1),
consistent with stronger stellar winds at the higher metallicities of the Sunburst
Arc: (or Z ∼ 0.7 Z⊙; Z. Martinez et al. 2025) and M4327: (or Z ∼ 0.3 Z⊙; M. Curti
et al. 2025b); and (3) the WR N iii λ4642 line is much stronger in RXCJ2248-ID3,
which lacks WR C iv λλ5803,5814 emission, while the Sunburst Arc and M4327 exhibit
both N iii and C iv emission. These differences support a scenario in which the
z ∼ 2 WR galaxies hosts both WC and WN stars, but the more metal-poor RXCJ2248-ID3
hosts a young population of WN stars with no or very little WC contribution.\r\n\r\nZoom
InZoom OutReset image size\r\nFigure 6. The blue WR region of the optical spectrum
of RXCJ2248-ID3 (purple) is shown in comparison to the z ∼ 2.37 Sunburst Arc spectrum
from T. E. Rivera-Thorsen et al. (2024, blue), which has been convolved to R ∼ 1000
to match RXCJ2248-ID3, and the z = 2.22 M4327 spectrum obtained from the DJA, but
originally presented in M. Curti et al. (2025b, turquoise). All three galaxies show
characteristic signs of hosting WN stars but RXCJ2248-ID3 shows striking N iii λ4642
emission that is much stronger than both the Sunburst Arc and M4327. On the other
hand, the Sunburst Arc and M4327 show broader He ii emission, which is expected
for more metal-rich galaxies as stellar winds scale with metallicity.\r\n\r\nDownload
figure:\r\n\r\nStandard imageHigh-resolution image\r\n5.2. Relative Chemical Enrichment
from WN Stars\r\nWith the highest redshift detection of WN stars to date, we now
explore their chemical yields as a source of the abundance pattern in RXCJ2248-ID3.
C. Charbonnel et al. (2023) performed a comparable analysis for the extreme N/O
ratio observed in GN-z11 and found that such rapid nitrogen enrichment could arise
from normal massive stars with M⋆ ∼ 20–120 M⊙ or from supermassive stars (M⋆ ≳ 1000
M⊙) in protoglobular cluster environments. Their results and those of R. Marques-Chaves
et al. (2024) further demonstrated that the short-lived WN-like phase can produce
large N/O ratios within a few megayears of the burst, consistent with the timescales
inferred here, but that the observed C/O ratios are only compatible over a very
short time interval. Building on this theoretical groundwork, C. Kobayashi & A.
Ferrara (2024) showed that a dual-burst chemical evolution model with a short WR-dominated
enrichment phase could also match GN-z11’s enrichment pattern. Similarly, R. Marques-Chaves
et al. (2024) used N yields from rotating massive stars to demonstrate that a young,
WR-dominated stellar population could reproduce the observed CNO enrichment pattern
in CEERS-1019.\r\n\r\nThe models above provide a valuable physical framework for
linking stellar yields to galaxy-scale abundance evolution at early times. To extend
the methodologies outlined by these works to RXCJ2248-ID3, we first examine the
dual-burst chemical evolution model of C. Kobayashi & A. Ferrara (2024), which was
fine-tuned to reproduce the enhanced N/O in GN-z11 (reported by R. Maiolino et al.
2024). This model invokes two bursts of star formation, where the second triggers
a narrow (≲1 Myr) phase of WR-dominated enrichment. While the model can easily reach
the N/O enrichment level of RXCJ2248-ID3, it was also designed to yield the higher
O/H and C/O abundances observed in GN-z11 than in RXCJ2248-ID3, which was achieved,
in part, by enrichment from WC stars. The updated O/H abundance for GN-z11 determined
by Z. Martinez et al. (2025) makes it consistent with some carbon enrichment from
WC stars, as shown in Figure 5. However, with a metallicity of only Z ∼ 0.10 Z⊙,
the WR population in RXCJ2248-ID3 is expected to consist of few WC stars, and so
an updated chemical evolution model is needed to match its unique CNO abundance
pattern.\r\n\r\nWe modify the C. Kobayashi & A. Ferrara (2024) dual-burst model
to be more appropriate for the metal-poor conditions in RXCJ2248-ID3. In particular,
the galactic chemical evolution (GCE) model uses the same star formation history
and the standard IMF (for 0.01–120 M⊙) as in the fiducial model in C. Kobayashi
& A. Ferrara (2024) but reduces the contribution from WC stars. C/O ratios of the
nucleosynthesis yields vary depending on the uncertain nuclear reaction rates (e.g.,
12C(α, γ)16O) and the treatment of convection and mass loss (C. Kobayashi et al.
2006). In the updated model, 12C and 16O yields are taken from C. Kobayashi et al.
(2020) for all mass ranges of stars but the contributions from the WC wind phase
is scaled to ∼15% in order to match the empirical trends and theoretical expectations
that most massive stars will have insufficient winds to remove their He envelopes
at such low metallicities.\r\n\r\nWe plot the updated metal-poor dual-burst model
in the bottom row of Figure 4 as a time-series of points that are color coded by
the age since the onset of the second burst. In this model, the observed N/O, O/H,
and C/O abundances of RXCJ2248-ID3 are reached simultaneously ∼4.2 Myr after the
onset of the second burst. This young age is consistent with enrichment from WN
stars and with the derived clump age of Myr (A. Claeyssens 2025). Thus, the N/O-enhanced
and relatively C/O-deficient conditions in RXCJ2248-ID3 are produced by a short-lived
evolutionary phase following intense, bursty star formation.\r\n\r\nWe note that
the duration and impact of the WN phase may be significantly extended if the stars
evolve in binary systems. In the M. Limongi & A. Chieffi (2018) single-star models,
the WN phase typically lasts ∼0.03–0.3 Myr and, due to the metallicity-dependent
winds, require high initial masses (∼40 M⊙) to expose the He- and N-rich layers.
However, in close binaries, envelope stripping via mass transfer or common-envelope
evolution can induce WR phases in lower-mass stars (20–30 M⊙), largely independent
of the stellar metallicity. This channel can significantly prolong the WN lifetime
(up to ∼1 Myr) depending on the binary mass ratio and separation (e.g., J. J. Eldridge
et al. 2017; Y. Götberg et al. 2019; D. R. Aguilera-Dena et al. 2022). As a result,
binary evolution may enhance both the frequency and duration of the chemically selective
N/O enrichment phase, such as that observed in RXCJ2248-ID. On the other hand, L.
Boco et al. (2025) successfully modeled observations of single WR stars in the SMC,
suggesting that binary stripping may not be required to produce WR stars at low
metallicity. Clearly, the frequency, lifetimes, and formation channels of WR stars
in low-metallicity environments are not yet well understood. Future work incorporating
current binary and single star WR pathways into chemical evolution models may, therefore,
be essential for capturing the full range of nitrogen feedback in low-metallicity
starbursts at high redshift.\r\n\r\nTaken together, the massive star enrichment
scenario presented here, and explored in C. Charbonnel et al. (2023), R. Marques-Chaves
et al. (2024), and C. Kobayashi & A. Ferrara (2024), demonstrates that selective
enrichment of nitrogen by WN-dominated feedback can naturally reproduce the observed
CNO abundance pattern in compact, low-metallicity starbursts such as RXCJ2248-ID3.
We can now paint a full picture of the ISM in RXCJ2248-ID3. The consistency of N/O
across ions spanning a wide range of ionization potentials suggests that the WN-enriched
material has been efficiently mixed throughout the ionized gas. This apparent chemical
homogeneity does not contradict the strong density and temperature stratification
inferred from our diagnostics: a clumpy or multiphase ISM can remain compositionally
uniform if the enriched ejecta are well dispersed. Given the extreme compactness
of RXCJ2248-ID3 (Re ≈ 20 pc), the characteristic dynamical and sound-crossing times
are only a few ×105 yr, comparable to or shorter than the duration of the WN phase
itself. Under such conditions, turbulent and radiative mixing can rapidly homogenize
the heavy-element yields, producing a chemically uniform yet physically structured
nebula.\r\n\r\n5.3. The N Mass Budget\r\nA crucial point of validation is whether
an intense burst of star formation so early in the Universe could have produced
the amount of N present in RXCJ2248-ID3. Similar to the analysis in R. Marques-Chaves
et al. (2024), we test this by first estimating the ionized nitrogen mass using\r\n\r\nwhere
the atomic mass ratio is mN/mH = 14 and N/H is the nitrogen abundance of the ionized
gas. The hydrogen gas mass MH is derived from the Hα luminosity as\r\n\r\nwhere
mH = 1.67 × 10−27 kg, h = 6.626 × 10−27 erg s−1, νHα is the frequency of the Hα
emission line, and cm3 s−1 is the Case B effective recombination coefficient for
Hα assuming a Te = 1.97 × 104 K. We estimate the Hα luminosity using a luminosity
distance of dL(z = 6.1025) =1.817 × 1029 cm, the collision-corrected narrow-component
Hα flux, and a magnification of μ = 6.8877 (L. Furtak et al. 2025) to be LHα = 1.20
× 1042 erg s−1. Combining this LHα with the equivalent width (EW)(Hα) = 1457 Å,
we derive the star formation rate (SFR) using the simulation-based SFR(Hα) calibration
from I. G. Kramarenko et al. (2026). This method was developed to be more appropriate
for the bursty conditions at high redshift than traditional calibrations and gives
SFR = 3.2 M⊙ yr−1, similar to the SED-derived SFRs assuming a constant SFH for 1
Myr () and 10 Myr (; see Table 1). Adopting a filling factor of ε = 0.01-0.10, assuming
a compact starburst (e.g., R. C. Kennicutt 1984; G. Stasińska & D. Schaerer 1997),
a density of 104 cm−3, and the measured N/H value, we calculate the ionized nitrogen
mass to be .\r\n\r\nWe then compute the total nitrogen mass that can be produced
by the recent burst of star formation using the integrated nitrogen yield produced
by the modified C. Kobayashi & A. Ferrara (2024) model for the SED-derived stellar
mass of assuming a continuous SFH over the duration of the second burst (∼4.2 Myr).
This results in a total N mass of 435 M⊙, implying that ∼% of the gas is retained
from the WN winds and ionized when matched to the expected ionized N mass (∼) from
the crudely calculated observed value. Thus, WN stars formed in a recent burst within
a compact, high-density, and very clumpy/inhomogeneous (low-filling-factor) environment
can plausibly explain the N mass in RXCJ2248-ID3, even at low metallicity (∼10%
Z⊙), without invoking a top-heavy IMF or exotic enrichment channels.\r\n\r\n5.4.
The Ephemeral Imprint of WN Star on High−z Galaxies\r\nThe prominence of N/O enhancement
at z ≳ 5 but relative rarity in local star-forming galaxies likely reflects a combination
of environmental conditions and evolutionary factors that are unique to the early
Universe. To examine the likely environments, we plot the SFR surface density (ΣSFR)
versus EW of Hβ in Figure 7 for both z ≳ 6 N emitters (RXCJ2248-ID3: M. W. Topping
et al. 2024, this work; GNz9p4: D. Schaerer et al. 2024; GN-z11, EW(Hβ) inferred
from Hγ: A. J. Bunker et al. 2023; S. Tacchella et al. 2023; GDS 3073: E. Vanzella
et al. 2010; H. Übler et al. 2023; X. Ji et al. 2024; CEERS-1019: R. L. Larson et
al. 2023; R. Marques-Chaves et al. 2024; A1703-zd6: M. W. Topping et al. 2025b)
and local star-forming galaxies with enhanced SFRs from the COS Legacy Archive Spectroscopic
SurveY (CLASSY; B. L. James et al. 2021; D. A. Berg et al. 2022; N/O from K. Z.
Arellano-Córdova et al. 2025). The high-redshift galaxies, such as RXCJ2248-ID3,
exhibit compact morphologies (Re ≲ 102 pc) that lead to much higher SFR surface
densities than seen at z ∼ 0, as well as bursty star formation histories that favor
the rapid buildup of massive stars capable of entering the short-lived WN phases
(M⋆ > 20 M⊙). The high-redshift N emitters also have high Hβ EWs (>200 Å) that are
indicative of young current bursts of star formation (<5 Myr). This suggests that
compactness alone is not enough to observe enhanced N/O; we must also observe these
galaxies at the fleeting moments of very young bursts when WR stars are most active.\r\n\r\nZoom
InZoom OutReset image size\r\nFigure 7. SFR surface density versus Hβ EW for high-redshift
(z > 5) N emitters versus z ∼ 0 galaxies from the CLASSY survey (SFR: D. A. Berg
et al. 2022; N/O: K. Z. Arellano-Córdova et al. 2025), which have enhanced SFRs
similar to z ∼ 2–3 galaxies. High-redshift N emitters are only observed at young
ages (≲5 Myr), as indicated by the high Hβ EWs (EW> 200 Å), and in compact, dense
environments (ΣSFR > 10 M⊙ yr−1 kpc−1). Note that RXCJ2248-ID3 is plotted here using
the properties derived from M. W. Topping et al. (2024) for continuous star formation
to be consistent with the other N-emitter measurements.\r\n\r\nDownload figure:\r\n\r\nStandard
imageHigh-resolution image\r\nFigure 7 suggests a scenario of elevated N/O at low
metallicity being preferentially seen in galaxies with high SFR surface densities
and young stellar ages (e.g., D. Schaerer et al. 2024; M. W. Topping et al. 2024;
Z. Martinez et al. 2025). R. Marques-Chaves et al. (2024) also suggest that the
elevated N/O and high-ionization spectrum of CEERS-1019 trace a short evolutionary
window of a ≲5 Myr burst dominated by WN-like feedback. Furthermore, the theoretical
models of C. Charbonnel et al. (2023) predict that such phases are characteristic
of young, dense stellar systems, potentially analogous to protoglobular clusters,
reinforcing that our observed WN-driven enrichment is a natural outcome of clustered,
bursty star formation at early times.\r\n\r\nAt low metallicity, weaker stellar
winds require higher initial masses for stars to reach the WR phase, so a larger
total stellar mass must form in a burst to produce a detectable population of WN
stars. In compact galaxies beyond cosmic noon, this condition is naturally met in
systems with high SFR surface densities, which statistically sample the upper IMF
more fully and produce a detectable population of WN stars (e.g., J. Brinchmann
et al. 2008; M. Shirazi & J. Brinchmann 2012). Furthermore, the WR enrichment signature
is short-lived: it must be captured during the brief WN-dominated phase (tburst
≲ 5 Myr and ΔtWN ≲ 0.3 Myr), before dilution from WC stars, CCSNe, or delayed AGB
enrichment. These timing constraints imply that only a small fraction of the star-forming
galaxies in the distant Universe will be caught in this phase. The detection of
WR-driven N/O enhancement at high redshift thus reflects a brief evolutionary stage
where intense, rapid feedback from a large number of WN stars briefly imprints nonuniform
elemental enrichment patterns (i.e., elevated N/O), which are expected to be quickly
washed away. As soon as the system evolves beyond the WN phase, subsequent WC or
CCSN yields will rapidly dilute the N excess and alter the overall abundance patter
(e.g., increasing C/O, lowering N/C).\r\n\r\nRecently, M. W. Topping et al. (2025b)
showed that galaxies with significant N iv] emission (corresponding to extreme N/O
enhancement), are found exclusively among galaxies with extreme [O iii]+Hβ EWs of
2600–4200 Å. Galaxies with such high [O iii]+Hβ EWs are in the upper 2% tail of
the EW distribution at z ≳ 4 and are outliers at z ∼ 0. This strongly suggests that
high N/O outliers are confined to the youngest stellar populations undergoing their
most intense bursts of star formation in the early Universe (e.g., R. Endsley et
al. 2023, 2025; J. Matthee et al. 2023; M. W. Topping et al. 2025b).\r\n\r\nIn this
context, M. W. Topping et al. (2025b) found that 30% of galaxies with EW[O III]
+ Hβ > 2000 Å show strong nitrogen emission, corresponding to ∼0.6% of their UV-selected
parent population. If this 0.6% population corresponds to enhanced N/O during the
ΔtWN ∼ 0.3 Myr WN phase, it would imply a characteristic burst timescale of ∼50
Myr. A practical consequence is that young bursts substantially increase the light-to-mass
ratios and, thus, the likelihood of detection in flux-limited samples (e.g., C.
A. Mason et al. 2023; J. B. Muñoz et al. 2023; G. Sun et al. 2023). Therefore, the
observed frequency of strong nitrogen emitters at fixed MUV is likely biased high
relative to their intrinsic abundance (e.g., at fixed stellar mass). Given the detectability
bias toward burst phases, this tburst may represent a lower limit, with the true
interval plausibly longer. This timescale is supported by recent analyses of the
scatter in the star-forming main sequence and time-resolved SFR indicators at z
∼ 3–9 that suggest burst cycles of tens-of-megayear timescales (albeit with broad
distributions, e.g., C. Simmonds et al. 2025). Thus, the combination of extreme-EW
selection and N iv] frequency provides a novel timing argument that WN-driven enrichment
is tightly coupled to very young, transient starburst phases beyond cosmic noon.\r\n\r\nTaken
together, the arguments presented in this work suggest that nitrogen outliers are
not exotic exceptions, but rather a brief, WN-enriched phase that any high-redshift
galaxy with sufficiently high SFR surface density can pass through. In contrast,
numerous low-redshift WR galaxies exhibit young populations that include WN and
WC stars but show little or no N/O enhancement (e.g., Y. I. Izotov et al. 2006;
C. Kehrig et al. 2013). This difference underscores that similar stellar populations
do not guarantee the same chemical signatures; instead, the extreme densities, compactness,
and rapid mixing timescales of high-redshift starbursts likely make WN-driven enrichment
both more pronounced and more transient. In this view, N/O outliers in the early
Universe are not anomalies, but rather are the chemical fingerprints of galaxies
caught midburst, showing fleeting yet inevitable markers of early galaxy evolution.\r\n\r\n6.
Conclusions\r\nWe have presented a detailed enrichment scenario by WN stars that
explains the extreme nitrogen enrichment in the metal-poor (∼10% Z⊙), high surface-density
(1.34 × 103 M⊙ pc−2), high-redshift (z = 6.1025), lensed galaxy RXCJ2248-ID3. These
measurements were made possible by exceptionally deep JWST/NIRSpec medium-resolution
spectroscopy of RXCJ2248-ID3, obtained as part of the GLIMPSE-D survey. The unprecedented
depth and S/N of the GLIMPSE-D spectrum allow spectral measurements typically limited
to the nearby Universe, including consistent broad components in the Balmer series
and [O iii] λ4364 and λλ4960,5008 lines, faint [Ar iv] λλ4713,4741 emission, and
signatures of WR stars. Specifically, we detected the emission characteristic of
WN-type stars, including strong N iii λ4642 and broadened He ii λ1640 and λ4687
emission, marking RXCJ2248-ID3 as the most distant galaxy to date with spectroscopic
detections of WR stars.\r\n\r\nWe performed a detailed nebular analysis, self-consistently
measuring the reddening, high-ionization temperature (Te(O+2)), and densities from
five different diagnostics across a wide ionization range. We measure a low reddening
value of from the Hγ/Hβ ratio but find an excess in the Hα/Hβ ratio of 0.204 due
to collisional excitation of Hα. The measured densities span the range of 1.15 ×
103 cm−3 ≤ ne ≤ 2.65 × 105 cm−3 and show strong evidence for nebular density stratification,
with systematically higher densities in the highest-ionization gas and UV emission
tracing gas at higher densities than those traced by optical diagnostics. This structure
implies a highly clumpy, multiphase ISM. We note that such high-density, multiphase
gas leads to densities from optical diagnostics that are biased to the low end of
the density range due to their low critical densities. Therefore, we recommend using
UV density diagnostics because they are more robust in high-density environments:
ne(Si+2), ne(C+2), and ne(N+3) trace the densities in the low-, intermediate-, and
high-ionization gas, respectively. As a result, we measure a direct-method metallicity
of .\r\n\r\nUsing the full rest-UV+optical spectra, we present the first robust,
consistent measurements of N/O abundance in any galaxy using three ionization stages
of nitrogen (N+/O+, N+2/O+2, N+3/O+2). The uniformity of our N/O measurements suggests
that the N/O enrichment is spatially extended and well mixed throughout the ionized
ISM. Empirical trends suggest C/O should follow a similar trend as N/O, and thus
also be enhanced. In contrast, we find C/O to be significantly depleted relative
to N/O, suggesting nonuniform elemental enrichment likely driven by WN stars with
little to no contribution from WC stars.\r\n\r\nThe CNO abundance pattern is best
reproduced by a modified version of the dual-burst chemical evolution model from
C. Kobayashi & A. Ferrara (2024) that reduces the contribution from WC stars relative
to WN stars, as expected in metal-poor environments. The resulting short-lived WN
phase ejects N-rich, C-poor material. We use this chemical evolution model to assess
whether the observed N mass can plausibly arise from the recent star formation in
RXCJ2248-ID3 and estimate an ionized N mass of 435 M⊙. This value is consistent
with the N mass estimated from the observed emission lines of M⊙ if % of the N gas
is ionized.\r\n\r\nThese results demonstrate that standard stellar evolution models
can reproduce both the CNO pattern and the total nitrogen mass observed without
invoking an exotic IMF or enrichment channel. The uniform N/O ratios across multiple
ionization zones further suggest that the WN yields were rapidly mixed into a relatively
pristine ambient ISM, preserving the global enhancement observed in RXCJ2248-ID3.
Although RXCJ2248-ID3 exhibits strong density and temperature stratification, this
structural complexity does not necessarily imply chemical inhomogeneity. The consistent
N/O ratios across ions tracing vastly different physical conditions indicate that
the enriched material was efficiently dispersed throughout the multiphase ISM. In
such a compact (Re ≈ 20 pc), high-pressure environment, turbulent and radiative
mixing can homogenize the chemical composition on timescales comparable to, or shorter
than, the brief WN phase itself, yielding a chemically uniform yet physically clumpy
nebula.\r\n\r\nImportantly, the abundance pattern and physical conditions observed
in RXCJ2248-ID3 can only be explained if the galaxy is caught during a narrow evolutionary
window within a few megayears of a massive, compact starburst when WN stars dominate
chemical feedback. At low metallicity, stars require higher initial masses to reach
the WR phase, making such enrichment episodes rare and dependent on sufficiently
high SFRs to fully populate the upper IMF. Furthermore, the WN phase itself is extremely
short-lived (∼0.03–0.3 Myr) and easily masked by subsequent WC winds, CCSNe, or
AGB stars contributions. These timing and SFR constraints make WR-driven N/O enhancement
a rare phenomenon associated with extreme starburst conditions that are more common
in the early Universe, and which are scarce in the local Universe.\r\n\r\nOur results
suggest that the WN-driven N/O enrichment we observe is not a peculiar property
of a single system, but rather a brief phase that essentially all high-redshift
galaxies (z > 5) with sufficiently high SFR surface densities to produce significant
numbers of WN stars likely undergo. In particular, the work of M. W. Topping et
al. (2025b) can be used to link N/O outliers to the most extreme [O iii]+Hβ EWs.
The observed frequency of such EWs combined with the short lifetime of the WN phase
implies a burst cycle of order ∼50 Myr, consistent with galaxies repeatedly cycling
through short, bursty episodes of enrichment. Thus, the GLIMPSE-D spectrum of RXCJ2248-ID3
provides not only the first direct evidence of WN stars shaping the chemical evolution
of z > 5 galaxies but also a timing argument that situates N/O outliers as a natural,
fleeting, phase of high-redshift star formation.\r\n\r\nTaken together, our findings
are a glimpse into a short-lived phase of chemically selective enrichment from WN
stars at cosmic dawn, providing a physically self-consistent solution to the extreme
N/O enhancement and relative C/O depletion observed in RXCJ2248-ID3 and galaxies
like it. Thus, RXCJ2248-ID3 serves as a benchmark case for interpreting chemically
enriched, stratified, multiphase starbursts in the early Universe.\r\n\r\nAcknowledgments\r\nWe
thank the referee for their thorough review of our calculations and analysis and
for their helpful suggestions, which greatly improved the robustness of our results
and the clarity of the text. 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 #9223. This
work has received funding from the Swiss State Secretariat for Education, Research
and Innovation (SERI) under contract No. MB22.00072, as well as from the Swiss National
Science Foundation (SNSF) through project grant 200020_207349. The Cosmic Dawn Center
(DAWN) is funded by the Danish National Research Foundation under grant DNRF140.
The Dunlap Institute is funded through an endowment established by the David Dunlap
family and the University of Toronto. We acknowledge the support of the Canadian
Space Agency (CSA) [25JWGO4A06]. HA acknowledges support from CNES, focused on the
JWST mission, and the Programme National Cosmology and Galaxies (PNCG) of CNRS/INSU
with INP and IN2P3, co-funded by CEA and CNES and support by the French National
Research Agency (ANR) under grant ANR-21-CE31-0838. The JWST data presented in this
article from program #9223 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: 10.17909/8642-1k68."
article_number: '112'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Danielle A.
full_name: Berg, Danielle A.
last_name: Berg
- first_name: Rohan P.
full_name: Naidu, Rohan P.
last_name: Naidu
- first_name: John
full_name: Chisholm, John
last_name: Chisholm
- first_name: Hakim
full_name: Atek, Hakim
last_name: Atek
- first_name: Seiji
full_name: Fujimoto, Seiji
last_name: Fujimoto
- first_name: Vasily
full_name: Kokorev, Vasily
last_name: Kokorev
- first_name: Lukas J.
full_name: Furtak, Lukas J.
last_name: Furtak
- first_name: Chiaki
full_name: Kobayashi, Chiaki
last_name: Kobayashi
- first_name: Daniel
full_name: Schaerer, Daniel
last_name: Schaerer
- first_name: Angela
full_name: Adamo, Angela
last_name: Adamo
- first_name: Qinyue
full_name: Fei, Qinyue
last_name: Fei
- first_name: Damien
full_name: Korber, Damien
last_name: Korber
- 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: Rui
full_name: Marques-Chaves, Rui
last_name: Marques-Chaves
- first_name: Zorayda
full_name: Martinez, Zorayda
last_name: Martinez
- first_name: Kristen B.W.
full_name: Mcquinn, Kristen B.W.
last_name: Mcquinn
- 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: Alberto
full_name: Saldana-Lopez, Alberto
last_name: Saldana-Lopez
- first_name: Daniel P.
full_name: Stark, Daniel P.
last_name: Stark
- first_name: Mabel G.
full_name: Stephenson, Mabel G.
last_name: Stephenson
- first_name: Tiger Yu Yang
full_name: Hsiao, Tiger Yu Yang
last_name: Hsiao
citation:
ama: 'Berg DA, Naidu RP, Chisholm J, et al. A fleeting GLIMPSE of N/O enrichment
at cosmic dawn: Evidence for Wolf Rayet N stars in a z = 6.1 galaxy. The Astrophysical
Journal. 2026;1003(2). doi:10.3847/1538-4357/ae5e4c'
apa: 'Berg, D. A., Naidu, R. P., Chisholm, J., Atek, H., Fujimoto, S., Kokorev,
V., … Hsiao, T. Y. Y. (2026). A fleeting GLIMPSE of N/O enrichment at cosmic dawn:
Evidence for Wolf Rayet N stars in a z = 6.1 galaxy. The Astrophysical Journal.
IOP Publishing. https://doi.org/10.3847/1538-4357/ae5e4c'
chicago: 'Berg, Danielle A., Rohan P. Naidu, John Chisholm, Hakim Atek, Seiji Fujimoto,
Vasily Kokorev, Lukas J. Furtak, et al. “A Fleeting GLIMPSE of N/O Enrichment
at Cosmic Dawn: Evidence for Wolf Rayet N Stars in a z = 6.1 Galaxy.” The Astrophysical
Journal. IOP Publishing, 2026. https://doi.org/10.3847/1538-4357/ae5e4c.'
ieee: 'D. A. Berg et al., “A fleeting GLIMPSE of N/O enrichment at cosmic
dawn: Evidence for Wolf Rayet N stars in a z = 6.1 galaxy,” The Astrophysical
Journal, vol. 1003, no. 2. IOP Publishing, 2026.'
ista: 'Berg DA, Naidu RP, Chisholm J, Atek H, Fujimoto S, Kokorev V, Furtak LJ,
Kobayashi C, Schaerer D, Adamo A, Fei Q, Korber D, Matthee JJ, Marques-Chaves
R, Martinez Z, Mcquinn KBW, Muñoz JB, Oesch PA, Saldana-Lopez A, Stark DP, Stephenson
MG, Hsiao TYY. 2026. A fleeting GLIMPSE of N/O enrichment at cosmic dawn: Evidence
for Wolf Rayet N stars in a z = 6.1 galaxy. The Astrophysical Journal. 1003(2),
112.'
mla: 'Berg, Danielle A., et al. “A Fleeting GLIMPSE of N/O Enrichment at Cosmic
Dawn: Evidence for Wolf Rayet N Stars in a z = 6.1 Galaxy.” The Astrophysical
Journal, vol. 1003, no. 2, 112, IOP Publishing, 2026, doi:10.3847/1538-4357/ae5e4c.'
short: D.A. Berg, R.P. Naidu, J. Chisholm, H. Atek, S. Fujimoto, V. Kokorev, L.J.
Furtak, C. Kobayashi, D. Schaerer, A. Adamo, Q. Fei, D. Korber, J.J. Matthee,
R. Marques-Chaves, Z. Martinez, K.B.W. Mcquinn, J.B. Muñoz, P.A. Oesch, A. Saldana-Lopez,
D.P. Stark, M.G. Stephenson, T.Y.Y. Hsiao, The Astrophysical Journal 1003 (2026).
date_created: 2026-05-31T22:02:12Z
date_published: 2026-05-20T00:00:00Z
date_updated: 2026-06-02T08:46:20Z
day: '20'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.3847/1538-4357/ae5e4c
external_id:
arxiv:
- '2511.13591'
file:
- access_level: open_access
checksum: 1058555fdede45e10fca25d74e7977bc
content_type: application/pdf
creator: dernst
date_created: 2026-06-02T08:46:08Z
date_updated: 2026-06-02T08:46:08Z
file_id: '21938'
file_name: 2026_AstrophysicalJour_Berg.pdf
file_size: 21249354
relation: main_file
success: 1
file_date_updated: 2026-06-02T08:46:08Z
has_accepted_license: '1'
intvolume: ' 1003'
issue: '2'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '05'
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'
scopus_import: '1'
status: public
title: 'A fleeting GLIMPSE of N/O enrichment at cosmic dawn: Evidence for Wolf Rayet
N stars in a z = 6.1 galaxy'
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: 1003
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
_id: '21923'
abstract:
- lang: eng
text: "The appearance of simulated natural phenomena heavily depends on the way
surfaces are textured. However, applying texture maps to dynamic deformable surfaces
presents a significant challenge, due to ever-shifting differences in length scales
involved. When these surfaces move and advect the texture along with them, their
final appearance degrades as deformed regions dramatically distort their texture
map. Modifications to the texture directly at the pixel level in response to the
deformation may introduce ghosting artifacts and look unnatural. In the real world,
the appearance of surface details on a deforming material changes through the
interplay of physical processes such as rupturing, exposure of internal structure,
or wrinkling. Motivated by these behaviors, in this work we explore how physical
principles can guide the texturing methods based on the measure of surface deformation.\r\nWe
present two novel wave-based procedural texturing algorithms which reproduce common
physical properties like advection and self-similarity, enabling the plausible
animation of deforming objects with extreme texture map distortions. Our algorithms
are fully procedural, require no actual physics simulation, and store no state
or history of deformation besides the input UV map, making them highly parallelizable
on the GPU and efficient enough for real-time applications. We show the versatility
of the method by animating physical phenomena with extreme deformations such as
flowing lava, stretching putty and outpouring sludge."
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "We thank the anonymous reviewers for their helpful comments, the
members of the Visual Computing Group at ISTA for their feedback. We also thank
Jonathan Gagnon for their help with running the Lapped Textures codes and SideFX
for the Houdini Education software licenses.\r\nImages in Fig. 2 by Kisoulou and
Vultured on Unsplash, Michal Jarmoluk and Public Domain Pictures from Pixabay and
Hawai‘i Volcanoes NPS on flickr. This research was supported by the Scientific Service
Units (SSU) of ISTA through resources provided by Scientific Computing and was funded
in part by the European Union (ERC-2021-COG 101045083 CoDiNA)."
article_number: '154'
article_processing_charge: Yes
article_type: original
author:
- first_name: Aleksei
full_name: Kalinov, Aleksei
id: 44b7120e-eb97-11eb-a6c2-e1557aa81d02
last_name: Kalinov
orcid: 0000-0003-2189-3904
- first_name: Mickaël
full_name: Ly, Mickaël
id: 6340d7f0-b48d-11eb-b10d-b7487e71d9f1
last_name: Ly
- first_name: Christian
full_name: Hafner, Christian
id: 400429CC-F248-11E8-B48F-1D18A9856A87
last_name: Hafner
- first_name: Christopher J
full_name: Wojtan, Christopher J
id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87
last_name: Wojtan
orcid: 0000-0001-6646-5546
citation:
ama: Kalinov A, Ly M, Hafner C, Wojtan C. Physics-inspired procedural texturing
of extremely deformable surfaces. ACM Transactions on Graphics. 45(4).
doi:10.1145/3811353
apa: 'Kalinov, A., Ly, M., Hafner, C., & Wojtan, C. (n.d.). Physics-inspired
procedural texturing of extremely deformable surfaces. ACM Transactions on
Graphics. Los Angeles, CA, United States: ACM. https://doi.org/10.1145/3811353'
chicago: Kalinov, Aleksei, Mickaël Ly, Christian Hafner, and Chris Wojtan. “Physics-Inspired
Procedural Texturing of Extremely Deformable Surfaces.” ACM Transactions on
Graphics. ACM, n.d. https://doi.org/10.1145/3811353.
ieee: A. Kalinov, M. Ly, C. Hafner, and C. Wojtan, “Physics-inspired procedural
texturing of extremely deformable surfaces,” ACM Transactions on Graphics,
vol. 45, no. 4. ACM.
ista: Kalinov A, Ly M, Hafner C, Wojtan C. Physics-inspired procedural texturing
of extremely deformable surfaces. ACM Transactions on Graphics. 45(4), 154.
mla: Kalinov, Aleksei, et al. “Physics-Inspired Procedural Texturing of Extremely
Deformable Surfaces.” ACM Transactions on Graphics, vol. 45, no. 4, 154,
ACM, doi:10.1145/3811353.
short: A. Kalinov, M. Ly, C. Hafner, C. Wojtan, ACM Transactions on Graphics 45
(n.d.).
conference:
end_date: 2026-07-23
location: Los Angeles, CA, United States
name: 'SIGGRAPH: International Conference and Exhibition on Computer Graphics and
Interactive Techniques'
start_date: 2026-07-19
corr_author: '1'
date_created: 2026-05-29T13:25:16Z
date_published: 2026-07-01T00:00:00Z
date_updated: 2026-06-02T08:56:50Z
day: '01'
ddc:
- '006'
department:
- _id: GradSch
- _id: ChWo
doi: 10.1145/3811353
file:
- access_level: open_access
checksum: ea165bf731ddd3045f83878dcb833672
content_type: video/mp4
creator: akalinov
date_created: 2026-05-29T13:19:33Z
date_updated: 2026-05-29T13:19:33Z
file_id: '21924'
file_name: tog454-article154-supplemental.mp4
file_size: 77337231
relation: main_file
success: 1
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content_type: video/mp4
creator: akalinov
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date_updated: 2026-05-29T13:19:37Z
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file_size: 226633977
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creator: akalinov
date_created: 2026-05-29T13:19:33Z
date_updated: 2026-05-29T13:19:33Z
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file_name: tog454-article154-supplemental.pdf
file_size: 6793867
relation: main_file
success: 1
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content_type: application/pdf
creator: akalinov
date_created: 2026-05-29T13:19:36Z
date_updated: 2026-05-29T13:19:36Z
file_id: '21927'
file_name: tog454-article154-main-1.pdf
file_size: 84173392
relation: main_file
success: 1
file_date_updated: 2026-05-29T13:19:37Z
has_accepted_license: '1'
intvolume: ' 45'
issue: '4'
keyword:
- Procedural animation
language:
- iso: eng
month: '07'
oa: 1
oa_version: Accepted Version
project:
- _id: 34bc2376-11ca-11ed-8bc3-9a3b3961a088
grant_number: '101045083'
name: Computational Discovery of Numerical Algorithms for Animation and Simulation
of Natural Phenomena
publication: ACM Transactions on Graphics
publication_identifier:
issn:
- 0730-0301
publication_status: inpress
publisher: ACM
quality_controlled: '1'
status: public
title: Physics-inspired procedural texturing of extremely deformable surfaces
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: 45
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21915'
abstract:
- lang: eng
text: Hydrological models commonly use very simple snow accumulation and melt models
based on air temperature information, namely, a temperature threshold for snow
accumulation as well as for snowmelt, and a melt factor. This utility emerges
due to the simplicity, efficiency, and generally good performance of such models
if sufficient calibration information is available. At scales beyond single gauged
catchments, the estimation and evaluation of the temperature thresholds and the
melt factor has been difficult due to a lack of observations on snow accumulation
and melt. Using a recently published Northern Hemisphere snow water equivalent
dataset (NH-SWE) and co-located climate station observations of temperature and
precipitation (4736 stations across the Northern Hemisphere), this work estimates
melt factors and temperature thresholds for snow modelling based on station observations
and provides the first large-scale and long-term (1950–2023) evaluation of a simple
temperature-index snow model and its parameters across a diverse range of snow
climates. Our study reveals that the 0 °C as precipitation-phase threshold captures
most snowfall days (89 %) and the 0 °C as snowmelt initiation threshold captures
most snowmelt days (76 %). Adjusting large-scale uniform threshold values does
not consistently improve performance across all snow accumulation and melt metrics.
Estimated melt factors based on observations converge towards 3–5 mm (°C d)−1
for deeper snowpack climates (peak snow water equivalent >300 mm), but their estimation
may be more challenging for colder climates with shallower snowpacks (<300 mm),
conditions where the derived melt factors cover a wider range (1 to 12 mm (°C d)−1)
and a much higher interannual and spatial variability. The temperature-index snow
model performs consistently well, on average, across the available Northern Hemisphere
data set for estimating long-term mean values of seasonal snow cover onset, snowmelt
season onset, mean snow accumulation and snowmelt rates, but challenges may arise
due to biases in temperature records or solid precipitation undercatch. Peak snow
water equivalent is likely underestimated for deep or alpine snowpacks, while
it is likely overestimated for shallow snowpacks in the coldest and continental
climates. The best median performance of the temperature-index approach lies on
relatively shallow snowpacks in temperate climates. This study provides valuable
insights into temperature-threshold snowfall modelling and temperature-index melt
modelling for applications across diverse climates and environments, and the results
should help refine regional modelling approaches to enhance our understanding
of snowpack responses to global warming.
acknowledgement: 'AFB acknowledges funding from the UK''s Natural Environment Research
Council (NERC) CENTA2 doctoral training program, grant number NE/S007350/1. AFB
acknowledges support from the School of Geography, Earth and Environmental Science
research fund. The computations described in this paper were performed using the
University of Birmingham''s BlueBEAR HPC service, which provides a High Performance
Computing service to the University''s research community. See http://www.birmingham.ac.uk/bear
(last access: 15 December 2025) for more details. This research has been supported
by the Natural Environment Research Council (grant no. CENTA2 NE/S007350/1).'
article_processing_charge: Yes
article_type: original
author:
- first_name: Adrià
full_name: Fontrodona-Bach, Adrià
id: f06891fd-9f42-11ee-8632-a20971c43046
last_name: Fontrodona-Bach
- first_name: Bettina
full_name: Schaefli, Bettina
last_name: Schaefli
- first_name: Ross
full_name: Woods, Ross
last_name: Woods
- first_name: Joshua R.
full_name: Larsen, Joshua R.
last_name: Larsen
citation:
ama: Fontrodona-Bach A, Schaefli B, Woods R, Larsen JR. Estimating robust melt factors
and temperature thresholds for snow modelling across the Northern Hemisphere.
Hydrology and Earth System Sciences. 2026;30(9):2613-2636. doi:10.5194/hess-30-2613-2026
apa: Fontrodona-Bach, A., Schaefli, B., Woods, R., & Larsen, J. R. (2026). Estimating
robust melt factors and temperature thresholds for snow modelling across the Northern
Hemisphere. Hydrology and Earth System Sciences. Copernicus Publications.
https://doi.org/10.5194/hess-30-2613-2026
chicago: Fontrodona-Bach, Adrià, Bettina Schaefli, Ross Woods, and Joshua R. Larsen.
“Estimating Robust Melt Factors and Temperature Thresholds for Snow Modelling
across the Northern Hemisphere.” Hydrology and Earth System Sciences. Copernicus
Publications, 2026. https://doi.org/10.5194/hess-30-2613-2026.
ieee: A. Fontrodona-Bach, B. Schaefli, R. Woods, and J. R. Larsen, “Estimating robust
melt factors and temperature thresholds for snow modelling across the Northern
Hemisphere,” Hydrology and Earth System Sciences, vol. 30, no. 9. Copernicus
Publications, pp. 2613–2636, 2026.
ista: Fontrodona-Bach A, Schaefli B, Woods R, Larsen JR. 2026. Estimating robust
melt factors and temperature thresholds for snow modelling across the Northern
Hemisphere. Hydrology and Earth System Sciences. 30(9), 2613–2636.
mla: Fontrodona-Bach, Adrià, et al. “Estimating Robust Melt Factors and Temperature
Thresholds for Snow Modelling across the Northern Hemisphere.” Hydrology and
Earth System Sciences, vol. 30, no. 9, Copernicus Publications, 2026, pp.
2613–36, doi:10.5194/hess-30-2613-2026.
short: A. Fontrodona-Bach, B. Schaefli, R. Woods, J.R. Larsen, Hydrology and Earth
System Sciences 30 (2026) 2613–2636.
corr_author: '1'
date_created: 2026-05-24T22:01:32Z
date_published: 2026-05-04T00:00:00Z
date_updated: 2026-06-02T09:24:00Z
day: '04'
ddc:
- '550'
department:
- _id: FrPe
doi: 10.5194/hess-30-2613-2026
file:
- access_level: open_access
checksum: 8bde4775545f9e049ea3806144b0d5f1
content_type: application/pdf
creator: dernst
date_created: 2026-06-02T09:22:26Z
date_updated: 2026-06-02T09:22:26Z
file_id: '21940'
file_name: 2026_HydrologyEarthSystemSciences_FontrodonaBach.pdf
file_size: 11250378
relation: main_file
success: 1
file_date_updated: 2026-06-02T09:22:26Z
has_accepted_license: '1'
intvolume: ' 30'
issue: '9'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: 2613-2636
publication: Hydrology and Earth System Sciences
publication_identifier:
eissn:
- 1607-7938
issn:
- 1027-5606
publication_status: published
publisher: Copernicus Publications
quality_controlled: '1'
scopus_import: '1'
status: public
title: Estimating robust melt factors and temperature thresholds for snow modelling
across the Northern Hemisphere
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: 30
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21917'
abstract:
- lang: eng
text: A defining feature of quantum many-body systems is the exponential scaling
of the Hilbert space with the number of degrees of freedom. This exponential complexity
naïvely renders a complete state characterization, for instance via the complete
set of bipartite Renyi entropies for all disjoint regions, a challenging task.
Recently, a compact way of storing subregions' purities by encoding them as amplitudes
of a fictitious quantum wave function, known as entanglement feature, was proposed.
Notably, the entanglement feature can be a simple object even for highly entangled
quantum states. However the complexity and practical usage of the entanglement
feature for general quantum states has not been explored. In this work, we demonstrate
that the entanglement feature can be efficiently learned using only a polynomial
amount of samples in the number of degrees of freedom through the so-called tensor
cross interpolation (TCI) algorithm, assuming it is expressible as a finite bond
dimension MPS. We benchmark this learning process on Haar and random MPS states,
confirming analytic expectations. Applying the TCI algorithm to quantum eigenstates
of various one dimensional quantum systems, we identify cases where eigenstates
have entanglement feature learnable with TCI. We conclude with possible applications
of the learned entanglement feature, such as quantifying the distance between
different entanglement patterns and finding the optimal one-dimensional ordering
of physical indices in a given state, highlighting the potential utility of the
proposed purity interpolation method.
acknowledgement: "We acknowledge useful discussions with Richard Küng\r\non the interpolation
methods and error spreading, Ilia\r\nA. Luchnikov, Margarita Davydova, and, in particular,
Hiroshi Shinaoka, Marc Ritter, Yuriel Nuñez\r\nfor useful discussions about TCI
and the various\r\nworkarounds within the TensorCrossInterpolation.jl\r\nlibrary.
We also acknowledge the comments of anonymous Referee B, that encouraged us to expand
the\r\nmanuscript with discussion of additional applications\r\nof entanglement
feature in Section 4.3. M.S. acknowledges discussions with D. V. Savostyanov at
the 2nd\r\nInternational Quantum Tensor Networks (IQTN) plenary meeting at Flatiron
Institute’s Center for Computational Quantum Physics (CCQ) for introduction\r\nto
the TCI approach. D.K and M.S. acknowledge support by the European Research Council
(ERC) under We acknowledge useful discussions with Richard Küng\r\non the interpolation
methods and error spreading, Ilia\r\nA. Luchnikov, Margarita Davydova, and, in particular,
Hiroshi Shinaoka, Marc Ritter, Yuriel Nuñez\r\nfor useful discussions about TCI
and the various\r\nworkarounds within the TensorCrossInterpolation.jl\r\nlibrary.
We also acknowledge the comments of anonymous Referee B, that encouraged us to expand
the\r\nmanuscript with discussion of additional applications\r\nof entanglement
feature in Section 4.3. M.S. acknowledges discussions with D. V. Savostyanov at
the 2nd\r\nInternational Quantum Tensor Networks (IQTN) plenary meeting at Flatiron
Institute’s Center for Computational Quantum Physics (CCQ) for introduction\r\nto
the TCI approach. D.K and M.S. acknowledge support by the European Research Council
(ERC) under We acknowledge useful discussions with Richard Küng\r\non the interpolation
methods and error spreading, Ilia\r\nA. Luchnikov, Margarita Davydova, and, in particular,
Hiroshi Shinaoka, Marc Ritter, Yuriel Nuñez\r\nfor useful discussions about TCI
and the various\r\nworkarounds within the TensorCrossInterpolation.jl\r\nlibrary.
We also acknowledge the comments of anonymous Referee B, that encouraged us to expand
the\r\nmanuscript with discussion of additional applications\r\nof entanglement
feature in Section 4.3. M.S. acknowledges discussions with D. V. Savostyanov at
the 2nd\r\nInternational Quantum Tensor Networks (IQTN) plenary meeting at Flatiron
Institute’s Center for Computational Quantum Physics (CCQ) for introduction\r\nto
the TCI approach. D.K and M.S. acknowledge support by the European Research Council
(ERC) under the European Union’s Horizon 2020 research and innovation program (Grant
Agreement No. 850899).\r\nR.V. acknowledges partial support from the US Department
of Energy, Office of Science, Basic Energy\r\nSciences, under award No. DE-SC0023999,
and the\r\nSwiss National Science Foundation (grant 10008234).\r\nThis research
was supported in part by grant NSF\r\nPHY-2309135 to the Kavli Institute for Theoretical\r\nPhysics
(KITP)"
article_number: '2114'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Dmytro
full_name: Kolisnyk, Dmytro
id: 530a7320-5355-11ee-ae5a-82a46997aaa7
last_name: Kolisnyk
orcid: 0000-0002-8612-8202
- first_name: Raimel A
full_name: Medina Ramos, Raimel A
id: CE680B90-D85A-11E9-B684-C920E6697425
last_name: Medina Ramos
orcid: 0000-0002-5383-2869
- first_name: Romain
full_name: Vasseur, Romain
last_name: Vasseur
- first_name: Maksym
full_name: Serbyn, Maksym
id: 47809E7E-F248-11E8-B48F-1D18A9856A87
last_name: Serbyn
orcid: 0000-0002-2399-5827
citation:
ama: Kolisnyk D, Medina Ramos RA, Vasseur R, Serbyn M. Tensor cross interpolation
of purities in quantum many-body systems. Quantum. 2026;10. doi:10.22331/q-2026-05-22-2114
apa: Kolisnyk, D., Medina Ramos, R. A., Vasseur, R., & Serbyn, M. (2026). Tensor
cross interpolation of purities in quantum many-body systems. Quantum.
Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften.
https://doi.org/10.22331/q-2026-05-22-2114
chicago: Kolisnyk, Dmytro, Raimel A Medina Ramos, Romain Vasseur, and Maksym Serbyn.
“Tensor Cross Interpolation of Purities in Quantum Many-Body Systems.” Quantum.
Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften,
2026. https://doi.org/10.22331/q-2026-05-22-2114.
ieee: D. Kolisnyk, R. A. Medina Ramos, R. Vasseur, and M. Serbyn, “Tensor cross
interpolation of purities in quantum many-body systems,” Quantum, vol.
10. Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften,
2026.
ista: Kolisnyk D, Medina Ramos RA, Vasseur R, Serbyn M. 2026. Tensor cross interpolation
of purities in quantum many-body systems. Quantum. 10, 2114.
mla: Kolisnyk, Dmytro, et al. “Tensor Cross Interpolation of Purities in Quantum
Many-Body Systems.” Quantum, vol. 10, 2114, Verein zur Förderung des Open
Access Publizierens in den Quantenwissenschaften, 2026, doi:10.22331/q-2026-05-22-2114.
short: D. Kolisnyk, R.A. Medina Ramos, R. Vasseur, M. Serbyn, Quantum 10 (2026).
corr_author: '1'
date_created: 2026-05-26T19:39:12Z
date_published: 2026-05-22T00:00:00Z
date_updated: 2026-06-02T09:15:13Z
day: '22'
ddc:
- '530'
department:
- _id: MaSe
- _id: GradSch
doi: 10.22331/q-2026-05-22-2114
ec_funded: 1
external_id:
arxiv:
- '2503.17230'
file:
- access_level: open_access
checksum: f8ce78607ad06120cdf894dc8cef55da
content_type: application/pdf
creator: dernst
date_created: 2026-06-02T09:12:11Z
date_updated: 2026-06-02T09:12:11Z
file_id: '21939'
file_name: 2026_Quantum_Kolisnyk.pdf
file_size: 3284798
relation: main_file
success: 1
file_date_updated: 2026-06-02T09:12:11Z
has_accepted_license: '1'
intvolume: ' 10'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
call_identifier: H2020
grant_number: '850899'
name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: Quantum
publication_identifier:
eissn:
- 2521-327X
publication_status: published
publisher: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
quality_controlled: '1'
status: public
title: Tensor cross interpolation of purities in quantum many-body systems
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: 10
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21929'
abstract:
- lang: eng
text: 'The import of proteins into mitochondria poses fundamental mechanistic challenges:
aggregation-prone precursor proteins must be maintained in aqueous compartments
and threaded through narrow pores without becoming stuck or mislocalized. Recent
evidence from mitochondrial protein import studies and other chaperone systems
underscores the critical role of dynamics in balancing sufficiently tight binding,
promiscuity, specificity, and release. Dynamic binding of client precursor proteins
to import machinery components arises naturally from the avidity of their interactions.
Conformational entropy enhances their stability, while the multivalent nature
of these interactions ensures that client transfer to downstream insertases occurs
without a substantial energy barrier. Here, we discuss this emerging paradigm
of dynamic protein handling, using examples where dynamic structures have been
resolved and highlight outstanding questions.'
acknowledgement: We gratefully acknowledge research funding by the Austrian Science
Fund (FWF), projects 10.55776/PAT1647625 and 10.55776/I6223. We thank Prof. Long
Li (Peking University) for providing structural models and EM density for the TOM
and TIM23 complexes, used to generate part of Figure 3. Open Access funding provided
by Institute of Science and Technology Austria.
article_number: e70630
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Jakob
full_name: Schneider, Jakob
id: 64368429-eb97-11eb-a6c2-c980b1f44415
last_name: Schneider
- first_name: Undina
full_name: Guillerm, Undina
id: bb74f472-ae54-11eb-9835-bc9c22fb1183
last_name: Guillerm
- first_name: Caroline
full_name: Simoes Pereira, Caroline
id: 87266c4a-96d2-11ef-be2c-fe5633233ec3
last_name: Simoes Pereira
- first_name: Paul
full_name: Schanda, Paul
id: 7B541462-FAF6-11E9-A490-E8DFE5697425
last_name: Schanda
orcid: 0000-0002-9350-7606
citation:
ama: Schneider J, Guillerm U, Simoes Pereira C, Schanda P. Dynamic disorder is crucial
for mitochondrial protein import. Protein Science. 2026;35(6). doi:10.1002/pro.70630
apa: Schneider, J., Guillerm, U., Simoes Pereira, C., & Schanda, P. (2026).
Dynamic disorder is crucial for mitochondrial protein import. Protein Science.
Wiley. https://doi.org/10.1002/pro.70630
chicago: Schneider, Jakob, Undina Guillerm, Caroline Simoes Pereira, and Paul Schanda.
“Dynamic Disorder Is Crucial for Mitochondrial Protein Import.” Protein Science.
Wiley, 2026. https://doi.org/10.1002/pro.70630.
ieee: J. Schneider, U. Guillerm, C. Simoes Pereira, and P. Schanda, “Dynamic disorder
is crucial for mitochondrial protein import,” Protein Science, vol. 35,
no. 6. Wiley, 2026.
ista: Schneider J, Guillerm U, Simoes Pereira C, Schanda P. 2026. Dynamic disorder
is crucial for mitochondrial protein import. Protein Science. 35(6), e70630.
mla: Schneider, Jakob, et al. “Dynamic Disorder Is Crucial for Mitochondrial Protein
Import.” Protein Science, vol. 35, no. 6, e70630, Wiley, 2026, doi:10.1002/pro.70630.
short: J. Schneider, U. Guillerm, C. Simoes Pereira, P. Schanda, Protein Science
35 (2026).
corr_author: '1'
date_created: 2026-05-31T22:02:12Z
date_published: 2026-06-01T00:00:00Z
date_updated: 2026-06-02T07:26:34Z
day: '01'
ddc:
- '572'
department:
- _id: GradSch
- _id: PaSc
doi: 10.1002/pro.70630
external_id:
pmid:
- '42159315'
file:
- access_level: open_access
checksum: e0163459a7238fdcc3fc5e17bedcce9a
content_type: application/pdf
creator: dernst
date_created: 2026-06-02T07:23:12Z
date_updated: 2026-06-02T07:23:12Z
file_id: '21937'
file_name: 2026_ProteinScience_Schneider.pdf
file_size: 3897305
relation: main_file
success: 1
file_date_updated: 2026-06-02T07:23:12Z
has_accepted_license: '1'
intvolume: ' 35'
issue: '6'
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: bdb9578d-d553-11ed-ba76-ed5d39fce6f0
grant_number: I06223
name: Structure and mechanism of the mitochondrial MIM insertase
publication: Protein Science
publication_identifier:
eissn:
- 1469-896X
issn:
- 0961-8368
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
title: Dynamic disorder is crucial for mitochondrial protein import
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: 35
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21914'
abstract:
- lang: eng
text: 'Cyclic adenosine monophosphate (cAMP) is a fundamental second messenger involved
in diverse signaling pathways across both animals and plants. While the role of
3′,5′-cAMP has been extensively characterized, the biological significance of
its structural isomer, 2′,3′-cAMP, remains largely unexplored, particularly in
plants. Here, we show that 2′,3′-cAMP and 3′,5′-cAMP represent parallel signaling
systems in Arabidopsis thaliana, with different enzymatic origins and largely
distinct downstream effects. In vitro enzymatic assays show that plant adenylate
cyclases (ACs), including AFB5 and HpAC1, produce specifically 3′,5′-cAMP from
ATP, whereas the TIR domain of protein L7 also catalyzes the formation of 2′,3′-cAMP
from RNA. Comprehensive multiomics analyses reveal that two isomers elicit distinct
yet partially overlapping metabolic, proteomic, and transcriptional response:
2′,3′-cAMP activates broad, stress-adaptive gene expression reprogramming, while
3′,5′-cAMP fine-tunes responses related to nutrient status and cellular homeostasis.
Our findings establish the existence of dual cAMP signaling systems in plants,
each with specialized functions and provide insights into the complex regulatory
networks governing plant physiology.'
acknowledged_ssus:
- _id: MassSpec
- _id: LifeSc
acknowledgement: " We thank J. Chai and D. Yu for providing the MBP-fused L7TIR plasmid
and K. Jaworski (Nicolaus Copernicus University) for the GST-HpAC1 plasmid. We
also thank M. Randuch and L. Fiedler for providing vectors for recombinant AFB5
and ADCY. We are also grateful to E. Dutkiewicz, L. Trübestein, N. Krasnici and
A. Michaelis for excellent technical\r\nassistance. We acknowledge the support of
the LSF Mass Spectrometry Service and the Lab\r\nSupport Facility at the Institute
of Science and Technology Austria for their contributions,\r\nincluding consultation
on size exclusion chromatography, LC/MS experimental design,\r\nmetabolomics sample
preparation, LC/MS method optimization, data acquisition, raw data\r\nanalysis,
and absolute quantification. This project is supported by the European\r\nResearch
Council (ERC) under the European Union’s Horizon 2020 research and innovation\r\nprogram
(101142681 CYNIPS) and Austrian Science Fund (FWF; P 37051-B), both to J.Friml.\r\nWe
acknowledge the generous support of the Taif University Researchers Supporting\r\nProject:
TURSP-HC2022/02 and Max-Planck-Society to A.S. "
article_number: aea7828
article_processing_charge: Yes
article_type: original
author:
- first_name: Mingyue
full_name: Li, Mingyue
id: 01f96916-0235-11eb-9379-a323192643b7
last_name: Li
- first_name: Monika
full_name: Chodasiewicz, Monika
last_name: Chodasiewicz
- first_name: Malavika
full_name: Muraleedharan, Malavika
last_name: Muraleedharan
- first_name: Israel M.
full_name: Lopez, Israel M.
last_name: Lopez
- first_name: Michal
full_name: Gorka, Michal
last_name: Gorka
- first_name: Olga
full_name: Kerber, Olga
last_name: Kerber
- first_name: Saqer S.
full_name: Alotaibi, Saqer S.
last_name: Alotaibi
- first_name: Andrew D.L.
full_name: Nelson, Andrew D.L.
last_name: Nelson
- first_name: Rene
full_name: Lenobel, Rene
last_name: Lenobel
- first_name: Jaroslava
full_name: Friedecká, Jaroslava
last_name: Friedecká
- first_name: Aleksandra
full_name: Skirycz, Aleksandra
last_name: Skirycz
- first_name: Jiří
full_name: Friml, Jiří
id: 4159519E-F248-11E8-B48F-1D18A9856A87
last_name: Friml
orcid: 0000-0002-8302-7596
citation:
ama: Li M, Chodasiewicz M, Muraleedharan M, et al. Biogenesis and downstream effects
of 3’,5’ and 2’,3’ cAMP isomers in plants. Science Advances. 2026;12(19).
doi:10.1126/sciadv.aea7828
apa: Li, M., Chodasiewicz, M., Muraleedharan, M., Lopez, I. M., Gorka, M., Kerber,
O., … Friml, J. (2026). Biogenesis and downstream effects of 3’,5’ and 2’,3’ cAMP
isomers in plants. Science Advances. AAAS. https://doi.org/10.1126/sciadv.aea7828
chicago: Li, Mingyue, Monika Chodasiewicz, Malavika Muraleedharan, Israel M. Lopez,
Michal Gorka, Olga Kerber, Saqer S. Alotaibi, et al. “Biogenesis and Downstream
Effects of 3’,5’ and 2’,3’ CAMP Isomers in Plants.” Science Advances. AAAS,
2026. https://doi.org/10.1126/sciadv.aea7828.
ieee: M. Li et al., “Biogenesis and downstream effects of 3’,5’ and 2’,3’
cAMP isomers in plants,” Science Advances, vol. 12, no. 19. AAAS, 2026.
ista: Li M, Chodasiewicz M, Muraleedharan M, Lopez IM, Gorka M, Kerber O, Alotaibi
SS, Nelson ADL, Lenobel R, Friedecká J, Skirycz A, Friml J. 2026. Biogenesis and
downstream effects of 3’,5’ and 2’,3’ cAMP isomers in plants. Science Advances.
12(19), aea7828.
mla: Li, Mingyue, et al. “Biogenesis and Downstream Effects of 3’,5’ and 2’,3’ CAMP
Isomers in Plants.” Science Advances, vol. 12, no. 19, aea7828, AAAS, 2026,
doi:10.1126/sciadv.aea7828.
short: M. Li, M. Chodasiewicz, M. Muraleedharan, I.M. Lopez, M. Gorka, O. Kerber,
S.S. Alotaibi, A.D.L. Nelson, R. Lenobel, J. Friedecká, A. Skirycz, J. Friml,
Science Advances 12 (2026).
corr_author: '1'
date_created: 2026-05-24T22:01:31Z
date_published: 2026-05-08T00:00:00Z
date_updated: 2026-06-02T14:36:41Z
day: '08'
ddc:
- '580'
department:
- _id: JiFr
doi: 10.1126/sciadv.aea7828
external_id:
pmid:
- '42102187'
file:
- access_level: open_access
checksum: 75b8ef2db078652c750e34e9cd98a808
content_type: application/pdf
creator: dernst
date_created: 2026-06-02T14:33:55Z
date_updated: 2026-06-02T14:33:55Z
file_id: '21941'
file_name: 2026_ScienceAdv_Li2.pdf
file_size: 2014452
relation: main_file
success: 1
file_date_updated: 2026-06-02T14:33:55Z
has_accepted_license: '1'
intvolume: ' 12'
issue: '19'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 8f347782-16d5-11f0-9cad-8c19706ee739
grant_number: '101142681'
name: Cyclic nucleotides as second messengers in plants
- _id: 7bcece63-9f16-11ee-852c-ae94e099eeb6
grant_number: P37051
name: Guanylate cyclase activity of TIR1/AFBs auxin receptors
publication: Science Advances
publication_identifier:
eissn:
- 2375-2548
publication_status: published
publisher: AAAS
quality_controlled: '1'
scopus_import: '1'
status: public
title: Biogenesis and downstream effects of 3',5' and 2',3' cAMP isomers in plants
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: 12
year: '2026'
...
---
OA_place: repository
OA_type: green
_id: '21931'
abstract:
- lang: eng
text: In 1873, James C. Maxwell conjectured that the electric field generated by
n point charges in generic position has at most (n-1)^2 isolated zeroes. The first
(nonoptimal) upper bound was only obtained in 2007 by Gabrielov, Novikov, and
Shapiro, who also posed two additional interesting conjectures. In this article,
we give the best upper bound known to date on the number of zeroes of the electric
field, and construct a counterexample to Conjecture 1.8 by Gabrielov, Novikov,
and Shapiro that the number of equilibria cannot exceed those of the distance
function defined by the unit point charges. Finally, we note that it is quite
possible that Maxwell's quadratic upper bound is not tight, so it is prudent to
find lower bounds. Hence, we also explore examples and construct configurations
of charges achieving the highest ratios of the number of electric field zeroes
by point charges found to this day.
article_number: e70163
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Herbert
full_name: Edelsbrunner, Herbert
id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
last_name: Edelsbrunner
orcid: 0000-0002-9823-6833
- first_name: Christopher D
full_name: Fillmore, Christopher D
id: 35638A5C-AAC7-11E9-B0BF-5503E6697425
last_name: Fillmore
- first_name: Goncalo
full_name: Oliveira, Goncalo
id: 58abbde8-f455-11eb-a497-98c8fd71b905
last_name: Oliveira
citation:
ama: Edelsbrunner H, Fillmore CD, Oliveira G. Counting equilibria of the electrostatic
potential. Proceedings of the London Mathematical Society. 2026;132(5).
doi:10.1112/plms.70163
apa: Edelsbrunner, H., Fillmore, C. D., & Oliveira, G. (2026). Counting equilibria
of the electrostatic potential. Proceedings of the London Mathematical Society.
Wiley. https://doi.org/10.1112/plms.70163
chicago: Edelsbrunner, Herbert, Christopher D Fillmore, and Goncalo Oliveira. “Counting
Equilibria of the Electrostatic Potential.” Proceedings of the London Mathematical
Society. Wiley, 2026. https://doi.org/10.1112/plms.70163.
ieee: H. Edelsbrunner, C. D. Fillmore, and G. Oliveira, “Counting equilibria of
the electrostatic potential,” Proceedings of the London Mathematical Society,
vol. 132, no. 5. Wiley, 2026.
ista: Edelsbrunner H, Fillmore CD, Oliveira G. 2026. Counting equilibria of the
electrostatic potential. Proceedings of the London Mathematical Society. 132(5),
e70163.
mla: Edelsbrunner, Herbert, et al. “Counting Equilibria of the Electrostatic Potential.”
Proceedings of the London Mathematical Society, vol. 132, no. 5, e70163,
Wiley, 2026, doi:10.1112/plms.70163.
short: H. Edelsbrunner, C.D. Fillmore, G. Oliveira, Proceedings of the London Mathematical
Society 132 (2026).
corr_author: '1'
date_created: 2026-05-31T22:02:13Z
date_published: 2026-05-01T00:00:00Z
date_updated: 2026-06-02T09:24:18Z
day: '01'
department:
- _id: HeEd
- _id: TaHa
doi: 10.1112/plms.70163
external_id:
arxiv:
- '2501.05315'
intvolume: ' 132'
issue: '5'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.48550/arXiv.2501.05315
month: '05'
oa: 1
oa_version: Preprint
publication: Proceedings of the London Mathematical Society
publication_identifier:
eissn:
- 1460-244X
issn:
- 0024-6115
publication_status: published
publisher: Wiley
quality_controlled: '1'
related_material:
record:
- id: '21050'
relation: earlier_version
status: public
scopus_import: '1'
status: public
title: Counting equilibria of the electrostatic potential
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 132
year: '2026'
...
---
OA_place: publisher
OA_type: diamond
_id: '21932'
abstract:
- lang: eng
text: We present LLMQ, an end-to-end CUDA/C++ implementation for medium-sized language-model
training, e.g. 3B to 32B parameters, on affordable, commodity GPUs. These devices
are characterized by low memory availability and slow communication compared to
datacentre-grade GPUs. Consequently, we showcase a range of optimizations that
target these bottlenecks, including activation checkpointing, offloading, and
copy-engine based collectives. LLMQ is able to train or fine-tune a 7B model on
a single 16GB mid-range gaming card, or a 32B model on a workstation equipped
with 4 RTX 4090s. This is achieved while executing a standard 8-bit training pipeline,
without additional algorithmic approximations, and maintaining FLOP utilization
of around 50%. The efficiency of LLMQ rivals that of production-scale systems
on much more expensive cloud-grade GPUs.
acknowledgement: "We would like to thank contacts at NVIDIA (Vartika Singh, Nina Carrejo,
Kyla Wilkes, and Tijmen\r\nBlankevoort), HP (Curtis Burkhalter), and Datacrunch/Verda
(Paul Chang and Antonio\r\nDominguez) for hardware support that was essential to
this project. ES was supported in part\r\nby ERC Proof-of-Concept grant FastML."
alternative_title:
- PMLR
article_processing_charge: No
author:
- first_name: Erik
full_name: Schultheis, Erik
id: 2786b299-e6b0-11f0-91da-9243fe3ef96b
last_name: Schultheis
- first_name: Dan-Adrian
full_name: Alistarh, Dan-Adrian
id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
last_name: Alistarh
orcid: 0000-0003-3650-940X
citation:
ama: 'Schultheis E, Alistarh D-A. LLMQ: Efficient lower-precision LLM training for
consumer GPUs. In: 2nd Conference on Parsimony and Learning. Vol 328. ML
Research Press; 2026:265-284.'
apa: 'Schultheis, E., & Alistarh, D.-A. (2026). LLMQ: Efficient lower-precision
LLM training for consumer GPUs. In 2nd Conference on Parsimony and Learning
(Vol. 328, pp. 265–284). Stanford, CA, United States: ML Research Press.'
chicago: 'Schultheis, Erik, and Dan-Adrian Alistarh. “LLMQ: Efficient Lower-Precision
LLM Training for Consumer GPUs.” In 2nd Conference on Parsimony and Learning,
328:265–84. ML Research Press, 2026.'
ieee: 'E. Schultheis and D.-A. Alistarh, “LLMQ: Efficient lower-precision LLM training
for consumer GPUs,” in 2nd Conference on Parsimony and Learning, Stanford,
CA, United States, 2026, vol. 328, pp. 265–284.'
ista: 'Schultheis E, Alistarh D-A. 2026. LLMQ: Efficient lower-precision LLM training
for consumer GPUs. 2nd Conference on Parsimony and Learning. CPAL: Conference
on Parsimony and Learning, PMLR, vol. 328, 265–284.'
mla: 'Schultheis, Erik, and Dan-Adrian Alistarh. “LLMQ: Efficient Lower-Precision
LLM Training for Consumer GPUs.” 2nd Conference on Parsimony and Learning,
vol. 328, ML Research Press, 2026, pp. 265–84.'
short: E. Schultheis, D.-A. Alistarh, in:, 2nd Conference on Parsimony and Learning,
ML Research Press, 2026, pp. 265–284.
conference:
end_date: 2025-03-27
location: Stanford, CA, United States
name: 'CPAL: Conference on Parsimony and Learning'
start_date: 2025-03-24
corr_author: '1'
date_created: 2026-05-31T22:02:13Z
date_published: 2026-04-06T00:00:00Z
date_updated: 2026-06-03T05:53:30Z
day: '06'
ddc:
- '000'
department:
- _id: DaAl
file:
- access_level: open_access
checksum: 72f9a87c70f1e2105ef64050ee5017e5
content_type: application/pdf
creator: dernst
date_created: 2026-06-03T05:51:19Z
date_updated: 2026-06-03T05:51:19Z
file_id: '21942'
file_name: 2026_CPAL_Schultheis.pdf
file_size: 2099944
relation: main_file
success: 1
file_date_updated: 2026-06-03T05:51:19Z
has_accepted_license: '1'
intvolume: ' 328'
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
page: 265-284
publication: 2nd Conference on Parsimony and Learning
publication_identifier:
eissn:
- 2640-3498
publication_status: published
publisher: ML Research Press
quality_controlled: '1'
related_material:
link:
- relation: software
url: https://github.com/IST-DASLab/llmq
scopus_import: '1'
status: public
title: 'LLMQ: Efficient lower-precision LLM training for consumer GPUs'
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: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 328
year: '2026'
...
---
_id: '21916'
abstract:
- lang: eng
text: 'Social network graphs are central to graph learning research, serving as
standard benchmarks for algorithm evaluation. However, existing datasets focus
mainly on mainstream social media platforms whose structures are shaped notably
by algorithmic recommendations. This raises an important question: would alternative,
decentralized social networks exhibit different properties? We address this by
studying the Fediverse; a collection of decentralized social networks (such as
Mastodon and Lemmy). These platforms differ fundamentally from for-profit social
media, notably in decentralization and absence of recommendation algorithms, which
may yield distinct graph structures. We introduce Fedivertex, a dataset of over
400 graphs from seven decentralized networks, collected weekly over six months.
The dataset, released with a companion Python package to facilitate its use, supports
research on temporal and structural aspects of decentralized social networks.
In particular, we benchmark applications to decentralized machine learning and
community detection.'
article_processing_charge: No
author:
- first_name: Marc
full_name: Damie, Marc
last_name: Damie
- first_name: Edwige Audrey Lucienne
full_name: Cyffers, Edwige Audrey Lucienne
id: 20d4c299-977a-11ef-ae55-98b15ac64a57
last_name: Cyffers
citation:
ama: 'Damie M, Cyffers EAL. Fedivertex: A graph dataset based on decentralized Social
Media. In: 2026 Proceedings of the ACM Web Conference 2026. ACM; :8393-8396.
doi:10.1145/3774904.3792868'
apa: 'Damie, M., & Cyffers, E. A. L. (n.d.). Fedivertex: A graph dataset based
on decentralized Social Media. In 2026 Proceedings of the ACM Web Conference
2026 (pp. 8393–8396). Dubai: ACM. https://doi.org/10.1145/3774904.3792868'
chicago: 'Damie, Marc, and Edwige Audrey Lucienne Cyffers. “Fedivertex: A Graph
Dataset Based on Decentralized Social Media.” In 2026 Proceedings of the ACM
Web Conference 2026, 8393–96. ACM, n.d. https://doi.org/10.1145/3774904.3792868.'
ieee: 'M. Damie and E. A. L. Cyffers, “Fedivertex: A graph dataset based on decentralized
Social Media,” in 2026 Proceedings of the ACM Web Conference 2026, Dubai,
pp. 8393–8396.'
ista: 'Damie M, Cyffers EAL. Fedivertex: A graph dataset based on decentralized
Social Media. 2026 Proceedings of the ACM Web Conference 2026. WWW: Web Conference,
8393–8396.'
mla: 'Damie, Marc, and Edwige Audrey Lucienne Cyffers. “Fedivertex: A Graph Dataset
Based on Decentralized Social Media.” 2026 Proceedings of the ACM Web Conference
2026, ACM, pp. 8393–96, doi:10.1145/3774904.3792868.'
short: M. Damie, E.A.L. Cyffers, in:, 2026 Proceedings of the ACM Web Conference
2026, ACM, n.d., pp. 8393–8396.
conference:
end_date: 2026-07-03
location: Dubai
name: 'WWW: Web Conference'
start_date: 2026-06-29
date_created: 2026-05-24T22:01:32Z
date_published: 2026-04-12T00:00:00Z
date_updated: 2026-06-03T05:40:18Z
day: '12'
department:
- _id: ChLa
doi: 10.1145/3774904.3792868
language:
- iso: eng
month: '04'
oa_version: None
page: 8393-8396
publication: 2026 Proceedings of the ACM Web Conference 2026
publication_identifier:
isbn:
- '9798400723070'
publication_status: accepted
publisher: ACM
scopus_import: '1'
status: public
title: 'Fedivertex: A graph dataset based on decentralized Social Media'
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '20328'
abstract:
- lang: eng
text: We consider the standard overlap (math formular) of any bi-orthogonal family
of left and right eigenvectors of a large random matrix X with centred i.i.d.
entries and we prove that it decays as an inverse second power of the distance
between the corresponding eigenvalues. This extends similar results for the complex
Gaussian ensemble from Bourgade and Dubach [15], as well as Benaych-Georges and
Zeitouni [13], to any i.i.d. matrix ensemble in both symmetry classes. As a main
tool, we prove a two-resolvent local law for the Hermitisation of X uniformly
in the spectrum with optimal decay rate and optimal dependence on the density
near the spectral edge.
acknowledgement: Partially supported by ERC Advanced Grant “RMTBeyond” No. 101020331.
Partially supported by National Key R&D Program of China No. 2024YFA1013503.
article_number: '111180'
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Giorgio
full_name: Cipolloni, Giorgio
id: 42198EFA-F248-11E8-B48F-1D18A9856A87
last_name: Cipolloni
orcid: 0000-0002-4901-7992
- first_name: László
full_name: Erdös, László
id: 4DBD5372-F248-11E8-B48F-1D18A9856A87
last_name: Erdös
orcid: 0000-0001-5366-9603
- first_name: Yuanyuan
full_name: Xu, Yuanyuan
id: 7902bdb1-a2a4-11eb-a164-c9216f71aea3
last_name: Xu
orcid: 0000-0003-1559-1205
citation:
ama: Cipolloni G, Erdös L, Xu Y. Optimal decay of eigenvector overlap for non-Hermitian
random matrices. Journal of Functional Analysis. 2026;290(1). doi:10.1016/j.jfa.2025.111180
apa: Cipolloni, G., Erdös, L., & Xu, Y. (2026). Optimal decay of eigenvector
overlap for non-Hermitian random matrices. Journal of Functional Analysis.
Elsevier. https://doi.org/10.1016/j.jfa.2025.111180
chicago: Cipolloni, Giorgio, László Erdös, and Yuanyuan Xu. “Optimal Decay of Eigenvector
Overlap for Non-Hermitian Random Matrices.” Journal of Functional Analysis.
Elsevier, 2026. https://doi.org/10.1016/j.jfa.2025.111180.
ieee: G. Cipolloni, L. Erdös, and Y. Xu, “Optimal decay of eigenvector overlap for
non-Hermitian random matrices,” Journal of Functional Analysis, vol. 290,
no. 1. Elsevier, 2026.
ista: Cipolloni G, Erdös L, Xu Y. 2026. Optimal decay of eigenvector overlap for
non-Hermitian random matrices. Journal of Functional Analysis. 290(1), 111180.
mla: Cipolloni, Giorgio, et al. “Optimal Decay of Eigenvector Overlap for Non-Hermitian
Random Matrices.” Journal of Functional Analysis, vol. 290, no. 1, 111180,
Elsevier, 2026, doi:10.1016/j.jfa.2025.111180.
short: G. Cipolloni, L. Erdös, Y. Xu, Journal of Functional Analysis 290 (2026).
corr_author: '1'
date_created: 2025-09-10T05:46:07Z
date_published: 2026-01-01T00:00:00Z
date_updated: 2026-06-03T13:12:14Z
day: '01'
ddc:
- '510'
department:
- _id: LaEr
doi: 10.1016/j.jfa.2025.111180
ec_funded: 1
external_id:
arxiv:
- '2411.16572'
isi:
- '001583178200001'
oaworkid:
- w4413883397
file:
- access_level: open_access
checksum: ee53d5e695f0df11e017c8c9242a2b04
content_type: application/pdf
creator: dernst
date_created: 2026-01-05T13:05:47Z
date_updated: 2026-01-05T13:05:47Z
file_id: '20947'
file_name: 2026_JourFuncAnalysis_Cipolloni.pdf
file_size: 2503887
relation: main_file
success: 1
file_date_updated: 2026-01-05T13:05:47Z
has_accepted_license: '1'
intvolume: ' 290'
isi: 1
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
oaworkid: 1
project:
- _id: 62796744-2b32-11ec-9570-940b20777f1d
call_identifier: H2020
grant_number: '101020331'
name: Random matrices beyond Wigner-Dyson-Mehta
publication: Journal of Functional Analysis
publication_identifier:
issn:
- 0022-1236
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: Optimal decay of eigenvector overlap for non-Hermitian random matrices
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: 290
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '21951'
abstract:
- lang: eng
text: "The central engines of Little Red Dots (LRDs) may be “black hole stars” (BH*s),
early stages of\r\nblack hole growth characterized by dense gas envelopes. So
far, the most direct evidence for BH*s\r\ncomes from a handful of sources where
the host galaxy is completely outshone as suggested by their\r\nremarkably steep
Balmer breaks. Here we present a novel scheme to disentangle BH*s from their\r\nhost
galaxies assuming that the [O III]5008˚A line arises exclusively from the host.
Using a sample\r\nof 98 LRDs (z ≈ 2 − 9) with high quality NIRSpec/PRISM spectra,
we demonstrate that the hostsubtracted median stack displays a Balmer break >
2× stronger than massive quiescent galaxies,\r\nwith the rest-optical continuum
resembling a blackbody-like SED (Teff ≈ 4050 K, log(Lbol) ≈ 43.9\r\nerg s−1\r\n,
Reff ≈ 1300 au). We measure a steep Balmer decrement (Hα/Hβ > 10) and numerous\r\ndensity-sensitive
features (e.g., Fe II, He I, O I). These are hallmark signatures of dense gas
envelopes,\r\nproviding population-level evidence that BH*s indeed power LRDs.
In the median LRD, BH*s account\r\nfor ∼ 20% of the UV emission, ∼ 50% at the
Balmer break, and ∼ 90% at wavelengths longer\r\nthan Hα with the remainder arising
from the host. BH*s preferentially reside in low-mass galaxies\r\n(M⋆ ≈ 108 M⊙)
undergoing recent starbursts, as evidenced by extreme emission line EWs (e.g.,\r\n[O
III]5008˚A≈ 1100˚A, C III]≈ 12˚A), thereby favoring BH* origins linked to star-formation.
We show\r\nV-shaped LRD selections are biased to high BH*/host fractions (≳ 60%
at 5500˚A) – less dominant\r\nBH*s may be powering JWST’s blue broad-line AGN.
We find BH*s are so commonplace and transient\r\n(duty cycle ∼ 1%, lifetime ∼
10 Myrs) that every massive black hole may have once shone as a BH*.\r\n"
acknowledgement: "We thank the two anonymous referees for their insightful comments
that have strengthened this work.\r\nWQS and RPN acknowledge funding from JWST programs
GO-3516, GO-5224, and the MIT Undergraduate\r\nResearch Opportunities Program (UROP).
Support for\r\nthis work was provided by NASA through the NASA\r\nHubble Fellowship
grant HST-HF2-51515.001-A awarded\r\nby the Space Telescope Science Institute, which
is operated by the Association of Universities for Research in\r\nAstronomy, Incorporated,
under NASA contract NAS5-\r\n26555. RPN thanks Neil Pappalardo and Jane Pappalardo
for their generous support of the MIT Pappalardo Fellowships in Physics, and for
their enthusiasm\r\nand encouragement for pursuing the earliest galaxies and\r\nblack
holes. JM and AT acknowledge funding from the\r\nEuropean Union (ERC, AGENTS, 101076224).
KEH\r\nacknowledges support from the Independent Research Fund Denmark (DFF) under
grant 5251-00009B and cofunding by the European Union (ERC, HEAVYMETAL,\r\n101071865).
Views and opinions expressed are, however,\r\nthose of the authors only and do not
necessarily reflect\r\nthose of the European Union or the European Research\r\nCouncil.
Neither the European Union nor the granting\r\nauthority can be held responsible
for them. REH acknowledges support by the German Aerospace Center\r\n(DLR) and the
Federal Ministry for Economic Affairs\r\nand Energy (BMWi) through program 50OR2403
‘RUBIES’.\r\nThe data products presented herein were retrieved\r\nfrom the Dawn
JWST Archive (DJA). DJA is an initiative of the Cosmic Dawn Center (DAWN), which
is\r\nfunded by the Danish National Research Foundation under grant DNRF140. This
work is based on observations\r\nmade with the NASA/ESA/CSA James Webb Space\r\nTelescope.
The data were obtained from the Mikulski Archive for Space Telescopes at the Space
Telescope\r\nScience Institute, which is operated by the Association\r\nof Universities
for Research in Astronomy, Inc., under\r\nNASA contract NAS 5-03127 for JWST. Support
for\r\nprograms #3516, #5224, #5664 was provided by NASA\r\nthrough grants from
the Space Telescope Science Institute, which is operated by the Association of Universities\r\nfor
Research in Astronomy, Inc., under NASA contract\r\nNAS 5-03127.\r\nThe spectra
used in this paper are associated with programs 1180 (D’Eugenio et al. 2025d), 1181
(PI: D. Eisenstein), 1208 (Willott et al. 2022), 1210 (PI: N. Luetzgendorf), 1211
(Maseda et al. 2024), 1212 - 1215 (PI: N.\r\nLuetzgendorf), 1228 (Luhman et al.
2024b), 1229 (Luhman et al. 2024a), 1286 (PI: N. Luetzgendorf), 1287 (PI:\r\nK.
Isaak), 1345 (Finkelstein et al. 2023), 1433 (Hsiao\r\net al. 2024), 1747 (PI: G.
Roberts-Borsani), 2028 (Wang\r\net al. 2024c), 2073 (PI: J. Hennawi), 2198 (Barrufet\r\net
al. 2025), 2282 (Bradley et al. 2023), 2561 (Bezanson\r\net al. 2024), 2565 (Nanayakkara
et al. 2025), 2640 (PI:\r\nW. Best), 2750 (Arrabal Haro et al. 2023), 2756 (Mascia
et al. 2024), 2767 (Williams et al. 2023b), 2770 (PI:\r\nM. McCaughrean), 3073 (Castellano
et al. 2024), 3215\r\n(Eisenstein et al. 2025), 4106 (PI: E. Nelson), 4233 (de\r\nGraaff
et al. 2025c), 4446 (Frye et al. 2024), 4557 (PI: H.\r\nYan), 5105 (Shen et al.
2024), 5224 (PIs: P.A. Oesch &\r\nR.P. Naidu), 6368 (PI: M. Dickinson), 6541 (DeCoursey\r\net
al. 2025), 6585 (PI: D. Coulter), 6642 (PI: J. Muzerolle\r\nPage), and FRESCO IFU
(Matthee et al. 2024; Torralba\r\net al. 2025b).\r\nSoftware used in developing
this work includes:\r\nmatplotlib (Hunter 2007), jupyter (Kluyver et al.\r\n2016),
IPython (P´erez & Granger 2007), numpy\r\n(Oliphant 2015), scipy (Virtanen et al.
2020), TOPCAT\r\n(Taylor 2005), Astropy (Astropy Collaboration et al.\r\n2013),
msaexp (Brammer 2023)."
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Wendy Q.
full_name: Sun, Wendy Q.
last_name: Sun
- first_name: Rohan P.
full_name: Naidu, Rohan P.
last_name: Naidu
- 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: Anna
full_name: De Graaff, Anna
last_name: De Graaff
- first_name: John
full_name: Chisholm, John
last_name: Chisholm
- first_name: Jenny E.
full_name: Greene, Jenny E.
last_name: Greene
- first_name: Pascal A.
full_name: Oesch, Pascal A.
last_name: Oesch
- 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: Raphael E.
full_name: Hviding, Raphael E.
last_name: Hviding
- first_name: Gabriel
full_name: Brammer, Gabriel
last_name: Brammer
- first_name: Robert A.
full_name: Simcoe, Robert A.
last_name: Simcoe
- first_name: Sownak
full_name: Bose, Sownak
last_name: Bose
- first_name: Rychard
full_name: Bouwens, Rychard
last_name: Bouwens
- first_name: Pratika
full_name: Dayal, Pratika
last_name: Dayal
- first_name: Anna Christina
full_name: Eilers, Anna Christina
last_name: Eilers
- first_name: Qinyue
full_name: Fei, Qinyue
last_name: Fei
- first_name: Lukas J.
full_name: Furtak, Lukas J.
last_name: Furtak
- first_name: Rashmi
full_name: Gottumukkala, Rashmi
last_name: Gottumukkala
- first_name: Andy
full_name: Goulding, Andy
last_name: Goulding
- first_name: Kasper E.
full_name: Heintz, Kasper E.
last_name: Heintz
- first_name: Michaela
full_name: Hirschmann, Michaela
last_name: Hirschmann
- first_name: Vasily
full_name: Kokorev, Vasily
last_name: Kokorev
- first_name: Joel
full_name: Leja, Joel
last_name: Leja
- first_name: Zhaoran
full_name: Liu, Zhaoran
last_name: Liu
- first_name: Priyamvada
full_name: Natarajan, Priyamvada
last_name: Natarajan
- first_name: Andrew D.
full_name: Santarelli, Andrew D.
last_name: Santarelli
- first_name: David J.
full_name: Setton, David J.
last_name: Setton
- first_name: Aaron
full_name: Smith, Aaron
last_name: Smith
- first_name: Sandro
full_name: Tacchella, Sandro
last_name: Tacchella
- first_name: Marta
full_name: Volonteri, Marta
last_name: Volonteri
- first_name: Fabian
full_name: Walter, Fabian
last_name: Walter
- first_name: Andrea
full_name: Weibel, Andrea
last_name: Weibel
- first_name: Christina C.
full_name: Williams, Christina C.
last_name: Williams
citation:
ama: 'Sun WQ, Naidu RP, Matthee JJ, et al. Little Red Dot - Host Galaxy = Black
Hole Star: A gas-enshrouded heart at the center of every Little Red Dot. The
Open Journal of Astrophysics. 2026;9. doi:10.33232/001c.162505'
apa: 'Sun, W. Q., Naidu, R. P., Matthee, J. J., De Graaff, A., Chisholm, J., Greene,
J. E., … Williams, C. C. (2026). Little Red Dot - Host Galaxy = Black Hole Star:
A gas-enshrouded heart at the center of every Little Red Dot. The Open Journal
of Astrophysics. Maynooth Academic Publishing. https://doi.org/10.33232/001c.162505'
chicago: 'Sun, Wendy Q., Rohan P. Naidu, Jorryt J Matthee, Anna De Graaff, John
Chisholm, Jenny E. Greene, Pascal A. Oesch, et al. “Little Red Dot - Host Galaxy
= Black Hole Star: A Gas-Enshrouded Heart at the Center of Every Little Red Dot.”
The Open Journal of Astrophysics. Maynooth Academic Publishing, 2026. https://doi.org/10.33232/001c.162505.'
ieee: 'W. Q. Sun et al., “Little Red Dot - Host Galaxy = Black Hole Star:
A gas-enshrouded heart at the center of every Little Red Dot,” The Open Journal
of Astrophysics, vol. 9. Maynooth Academic Publishing, 2026.'
ista: 'Sun WQ, Naidu RP, Matthee JJ, De Graaff A, Chisholm J, Greene JE, Oesch PA,
Torralba Torregrosa A, Hviding RE, Brammer G, Simcoe RA, Bose S, Bouwens R, Dayal
P, Eilers AC, Fei Q, Furtak LJ, Gottumukkala R, Goulding A, Heintz KE, Hirschmann
M, Kokorev V, Leja J, Liu Z, Natarajan P, Santarelli AD, Setton DJ, Smith A, Tacchella
S, Volonteri M, Walter F, Weibel A, Williams CC. 2026. Little Red Dot - Host Galaxy
= Black Hole Star: A gas-enshrouded heart at the center of every Little Red Dot.
The Open Journal of Astrophysics. 9.'
mla: 'Sun, Wendy Q., et al. “Little Red Dot - Host Galaxy = Black Hole Star: A Gas-Enshrouded
Heart at the Center of Every Little Red Dot.” The Open Journal of Astrophysics,
vol. 9, Maynooth Academic Publishing, 2026, doi:10.33232/001c.162505.'
short: W.Q. Sun, R.P. Naidu, J.J. Matthee, A. De Graaff, J. Chisholm, J.E. Greene,
P.A. Oesch, A. Torralba Torregrosa, R.E. Hviding, G. Brammer, R.A. Simcoe, S.
Bose, R. Bouwens, P. Dayal, A.C. Eilers, Q. Fei, L.J. Furtak, R. Gottumukkala,
A. Goulding, K.E. Heintz, M. Hirschmann, V. Kokorev, J. Leja, Z. Liu, P. Natarajan,
A.D. Santarelli, D.J. Setton, A. Smith, S. Tacchella, M. Volonteri, F. Walter,
A. Weibel, C.C. Williams, The Open Journal of Astrophysics 9 (2026).
date_created: 2026-06-07T22:01:36Z
date_published: 2026-05-25T00:00:00Z
date_updated: 2026-06-08T08:25:40Z
day: '25'
ddc:
- '520'
department:
- _id: JoMa
doi: 10.33232/001c.162505
external_id:
arxiv:
- '2601.20929'
file:
- access_level: open_access
checksum: 33c4a444f7c37b3f47ecbd53eb187c1b
content_type: application/pdf
creator: dernst
date_created: 2026-06-08T08:23:37Z
date_updated: 2026-06-08T08:23:37Z
file_id: '21952'
file_name: 2026_OpenJourAstrophysics_Sun.pdf
file_size: 7591188
relation: main_file
success: 1
file_date_updated: 2026-06-08T08:23:37Z
has_accepted_license: '1'
intvolume: ' 9'
language:
- iso: eng
month: '05'
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 Open Journal of Astrophysics
publication_identifier:
eissn:
- 2565-6120
publication_status: published
publisher: Maynooth Academic Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Little Red Dot - Host Galaxy = Black Hole Star: A gas-enshrouded heart at
the center of every Little Red Dot'
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: gold
_id: '21949'
abstract:
- lang: eng
text: "Cardiac T1 mapping provides critical quantitative insights into myocardial
tissue composition, enabling the assessment of pathologies such as fibrosis, inflammation,
and edema.\r\nHowever, the inherently dynamic nature of the heart imposes strict
limits on acquisition\r\ntimes, making high-resolution T1 mapping a persistent
challenge. Compressed sensing (CS)\r\napproaches have reduced scan durations by
undersampling k-space and reconstructing images from partial data, and recent
studies show that jointly optimizing the undersampling\r\npatterns with the reconstruction
network can substantially improve performance. Still,\r\nmost current T1 mapping
pipelines rely on static, hand-crafted masks that do not exploit\r\nthe full acceleration
and accuracy potential. Furthermore, most existing methods do not\r\nlevarage
the physical T1 decay model in optimization. In this work, we introduce T1-\r\nPILOT:
an end-to-end method that explicitly incorporates the T1 signal relaxation model\r\ninto
the sampling–reconstruction framework to guide the learning of non-Cartesian trajectories,
cross-frame alignment, and T1 decay estimation. Through extensive experiments\r\non
the CMRxRecon dataset, T1-PILOT significantly outperforms several baseline strategies
(including learned single-mask and fixed radial or golden-angle sampling schemes),\r\nachieving
higher T1 map fidelity at greater acceleration factors. In particular, we observe
consistent gains in PSNR and VIF relative to existing methods, along with marked\r\nimprovements
in delineating finer myocardial structures. Our results highlight that optimizing
sampling trajectories in tandem with the physical relaxation model leads to both\r\nenhanced
quantitative accuracy and reduced acquisition times. Code for reproducing all\r\nexperiments
and results is available at https://github.com/tamirshor7/T1-PILOT"
alternative_title:
- PMLR
article_processing_charge: No
author:
- first_name: Tamir
full_name: Shor, Tamir
last_name: Shor
- first_name: Moti
full_name: Freiman, Moti
last_name: Freiman
- first_name: Chaim
full_name: Baskin, Chaim
last_name: Baskin
- first_name: Alexander
full_name: Bronstein, Alexander
id: 58f3726e-7cba-11ef-ad8b-e6e8cb3904e6
last_name: Bronstein
orcid: 0000-0001-9699-8730
citation:
ama: 'Shor T, Freiman M, Baskin C, Bronstein AM. T1-PILOT: Physics-informed learned
optimized trajectories for T1 mapping acceleration. In: Medical Imaging with
Deep Learning. Vol 315. ML Research Press; :1969-1982.'
apa: 'Shor, T., Freiman, M., Baskin, C., & Bronstein, A. M. (n.d.). T1-PILOT:
Physics-informed learned optimized trajectories for T1 mapping acceleration. In
Medical Imaging with Deep Learning (Vol. 315, pp. 1969–1982). Taipei, Taiwan:
ML Research Press.'
chicago: 'Shor, Tamir, Moti Freiman, Chaim Baskin, and Alex M. Bronstein. “T1-PILOT:
Physics-Informed Learned Optimized Trajectories for T1 Mapping Acceleration.”
In Medical Imaging with Deep Learning, 315:1969–82. ML Research Press,
n.d.'
ieee: 'T. Shor, M. Freiman, C. Baskin, and A. M. Bronstein, “T1-PILOT: Physics-informed
learned optimized trajectories for T1 mapping acceleration,” in Medical Imaging
with Deep Learning, Taipei, Taiwan, vol. 315, pp. 1969–1982.'
ista: 'Shor T, Freiman M, Baskin C, Bronstein AM. T1-PILOT: Physics-informed learned
optimized trajectories for T1 mapping acceleration. Medical Imaging with Deep
Learning. MIDL: Medical Imaging with Deep Learning, PMLR, vol. 315, 1969–1982.'
mla: 'Shor, Tamir, et al. “T1-PILOT: Physics-Informed Learned Optimized Trajectories
for T1 Mapping Acceleration.” Medical Imaging with Deep Learning, vol.
315, ML Research Press, pp. 1969–82.'
short: T. Shor, M. Freiman, C. Baskin, A.M. Bronstein, in:, Medical Imaging with
Deep Learning, ML Research Press, n.d., pp. 1969–1982.
conference:
end_date: 2026-07-10
location: Taipei, Taiwan
name: 'MIDL: Medical Imaging with Deep Learning'
start_date: 2026-07-08
corr_author: '1'
date_created: 2026-06-07T22:01:36Z
date_published: 2026-03-17T00:00:00Z
date_updated: 2026-06-08T08:05:24Z
day: '17'
ddc:
- '000'
department:
- _id: AlBr
has_accepted_license: '1'
intvolume: ' 315'
keyword:
- Cardiac T1 Mapping
- Trajectory Optimization and Reconstruction
- PhysicsInformed Deep-Learning
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://openreview.net/forum?id=nZaPtHbd6N#discussion
month: '03'
oa: 1
oa_version: Published Version
page: 1969-1982
publication: Medical Imaging with Deep Learning
publication_identifier:
eissn:
- 2640-3498
publication_status: accepted
publisher: ML Research Press
quality_controlled: '1'
related_material:
link:
- relation: software
url: https://github.com/tamirshor7/T1-PILOT
scopus_import: '1'
status: public
title: 'T1-PILOT: Physics-informed learned optimized trajectories for T1 mapping acceleration'
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: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 315
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21948'
abstract:
- lang: eng
text: The cerebral cortex comprises diverse neuron and glial cell types generated
by radial glial progenitors (RGPs) during development. Although RGPs broadly differentiate
according to temporally and spatially regulated molecular logics, the lineage
hierarchies linking individual progenitors to defined cell (sub)types are not
well understood. Clone-resolved transcriptomics, combining molecular barcoding
and single-cell RNA sequencing, allow high-resolution lineage tracing at the single-clone/cell
level across different species and models. In this mini-review, we synthesize
recent advances in this field, uncovering unexpected lineage relationships in
the developing brain, with a particular focus on the cerebral cortex. We further
highlight new insights into species-specific differences in the developmental
programs generating cell-type diversity, linking changes in clonal architecture
to lineage diversification during cortical evolution.
acknowledgement: We wish to thank all members of the Hippenmeyer laboratory at ISTA
for exciting discussions on the subject of this review. We apologize to colleagues
whose work we could not cite and/or discuss in the frame of the available space.
Work in the Hippenmeyer laboratory on the discussed topic is supported by ISTA institutional
funds, an EMBO LTF (ALTF 994–2023) to F.P., FWF SFB F78 (10.55776/F78) to S.H.,
and FWF Cluster of Excellence COE16 (10.55776/COE16) to S.H.
article_number: '102487'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Irene
full_name: Varela Martínez, Irene
id: a69b5985-8829-11f0-8fc2-d0af58f64471
last_name: Varela Martínez
- first_name: Fabrizia
full_name: Pipicelli, Fabrizia
id: 649134fd-d012-11ed-8f82-db1e5050f9ba
last_name: Pipicelli
- first_name: Simon
full_name: Hippenmeyer, Simon
id: 37B36620-F248-11E8-B48F-1D18A9856A87
last_name: Hippenmeyer
orcid: 0000-0003-2279-1061
citation:
ama: 'Varela Martínez I, Pipicelli F, Hippenmeyer S. Tracing cell lineages in the
developing brain: Insights from mosaic analysis and clone-resolved transcriptomics.
Current Opinion in Genetics and Development. 2026;99. doi:10.1016/j.gde.2026.102487'
apa: 'Varela Martínez, I., Pipicelli, F., & Hippenmeyer, S. (2026). Tracing
cell lineages in the developing brain: Insights from mosaic analysis and clone-resolved
transcriptomics. Current Opinion in Genetics and Development. Elsevier.
https://doi.org/10.1016/j.gde.2026.102487'
chicago: 'Varela Martínez, Irene, Fabrizia Pipicelli, and Simon Hippenmeyer. “Tracing
Cell Lineages in the Developing Brain: Insights from Mosaic Analysis and Clone-Resolved
Transcriptomics.” Current Opinion in Genetics and Development. Elsevier,
2026. https://doi.org/10.1016/j.gde.2026.102487.'
ieee: 'I. Varela Martínez, F. Pipicelli, and S. Hippenmeyer, “Tracing cell lineages
in the developing brain: Insights from mosaic analysis and clone-resolved transcriptomics,”
Current Opinion in Genetics and Development, vol. 99. Elsevier, 2026.'
ista: 'Varela Martínez I, Pipicelli F, Hippenmeyer S. 2026. Tracing cell lineages
in the developing brain: Insights from mosaic analysis and clone-resolved transcriptomics.
Current Opinion in Genetics and Development. 99, 102487.'
mla: 'Varela Martínez, Irene, et al. “Tracing Cell Lineages in the Developing Brain:
Insights from Mosaic Analysis and Clone-Resolved Transcriptomics.” Current
Opinion in Genetics and Development, vol. 99, 102487, Elsevier, 2026, doi:10.1016/j.gde.2026.102487.'
short: I. Varela Martínez, F. Pipicelli, S. Hippenmeyer, Current Opinion in Genetics
and Development 99 (2026).
corr_author: '1'
date_created: 2026-06-07T22:01:35Z
date_published: 2026-05-29T00:00:00Z
date_updated: 2026-06-08T07:42:16Z
day: '29'
ddc:
- '570'
department:
- _id: SiHi
doi: 10.1016/j.gde.2026.102487
external_id:
pmid:
- '42214837'
has_accepted_license: '1'
intvolume: ' 99'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1016/j.gde.2026.102487
month: '05'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 7c084566-9f16-11ee-852c-c88a1dbbf1cf
grant_number: ALTF 994-2023
name: Role of cell lineage in generating cell-type diversity in developing neocortex’
- _id: 059F6AB4-7A3F-11EA-A408-12923DDC885E
grant_number: F7805
name: Stem Cell Modulation in Neural Development and Regeneration/ P05-Molecular
Mechanisms of Neural Stem Cell Lineage Progression
publication: Current Opinion in Genetics and Development
publication_identifier:
eissn:
- 1879-0380
issn:
- 0959-437X
publication_status: epub_ahead
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Tracing cell lineages in the developing brain: Insights from mosaic analysis
and clone-resolved transcriptomics'
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: 99
year: '2026'
...
---
OA_type: closed access
_id: '21950'
abstract:
- lang: eng
text: One Health initiatives are modern paradigms for research and health care practices
in various fields. Concrete definitions of the One Health framework, however,
remain heterogeneous, leading to conceptual problems and uncertainties in the
application of the framework. This article discusses several approaches to the
One Health concept, and their associated consequences, with special focus on animal
experimentation. The first issue addressed is how One Health should be defined,
as well as what (and who) should be considered within a One Health approach. In
order to shed further light on this, we explore the history of animals in biomedical
science, highlighting historical milestones in the use of animal models, as well
as the development and current state of ethical considerations in the field of
animal experimentation. The second issue comes with the inclusion of animal experimentation
per se as part of the One Health concept. Therefore, particular attention is paid
to bioethical principles and the resulting problems that can arise when applying
them to the One Health concept. Arguments such as the idea of inequality between
humans and non-human animals, and the premise that all actions are done for the
benefit of humans, are raised and then used to explore the question of whether
the One Health concept is compatible with existing bioethical principles. Based
on the bioethical principles of protecting the environment, the biodiversity and
biosphere, this paper seeks an inclusive perspective of the One Health concept.
Successful solutions will be based on this concept, which embraces all living
beings. The authors conclude that a multispecies ethics approach could help create
a more ethical ecosystem that is aligned with the wellbeing of all life on a shared
planet.
article_processing_charge: No
article_type: original
author:
- first_name: Yesim Isil
full_name: Ulman, Yesim Isil
last_name: Ulman
- first_name: Nikos
full_name: Kostomitsopoulos, Nikos
last_name: Kostomitsopoulos
- first_name: Samuel
full_name: Camenzind, Samuel
last_name: Camenzind
- first_name: Maria
full_name: Kitsara, Maria
last_name: Kitsara
- first_name: Ilja Richard
full_name: Pavone, Ilja Richard
last_name: Pavone
- first_name: Sophie
full_name: Schober, Sophie
id: 80b0a0ef-4b9f-11ec-b119-8d9d94c4a1d8
last_name: Schober
citation:
ama: 'Ulman YI, Kostomitsopoulos N, Camenzind S, Kitsara M, Pavone IR, Schober S.
Emerging bioethical conflicts: One Health and animal experimentation. Alternatives
to Laboratory Animals. 2026. doi:10.1177/02611929261453330'
apa: 'Ulman, Y. I., Kostomitsopoulos, N., Camenzind, S., Kitsara, M., Pavone, I.
R., & Schober, S. (2026). Emerging bioethical conflicts: One Health and animal
experimentation. Alternatives to Laboratory Animals. SAGE Publications.
https://doi.org/10.1177/02611929261453330'
chicago: 'Ulman, Yesim Isil, Nikos Kostomitsopoulos, Samuel Camenzind, Maria Kitsara,
Ilja Richard Pavone, and Sophie Schober. “Emerging Bioethical Conflicts: One Health
and Animal Experimentation.” Alternatives to Laboratory Animals. SAGE Publications,
2026. https://doi.org/10.1177/02611929261453330.'
ieee: 'Y. I. Ulman, N. Kostomitsopoulos, S. Camenzind, M. Kitsara, I. R. Pavone,
and S. Schober, “Emerging bioethical conflicts: One Health and animal experimentation,”
Alternatives to Laboratory Animals. SAGE Publications, 2026.'
ista: 'Ulman YI, Kostomitsopoulos N, Camenzind S, Kitsara M, Pavone IR, Schober
S. 2026. Emerging bioethical conflicts: One Health and animal experimentation.
Alternatives to Laboratory Animals.'
mla: 'Ulman, Yesim Isil, et al. “Emerging Bioethical Conflicts: One Health and Animal
Experimentation.” Alternatives to Laboratory Animals, SAGE Publications,
2026, doi:10.1177/02611929261453330.'
short: Y.I. Ulman, N. Kostomitsopoulos, S. Camenzind, M. Kitsara, I.R. Pavone, S.
Schober, Alternatives to Laboratory Animals (2026).
corr_author: '1'
date_created: 2026-06-07T22:01:36Z
date_published: 2026-01-01T00:00:00Z
date_updated: 2026-06-08T08:13:29Z
day: '01'
department:
- _id: PreCl
doi: 10.1177/02611929261453330
language:
- iso: eng
month: '01'
oa_version: None
publication: Alternatives to Laboratory Animals
publication_identifier:
eissn:
- 2632-3559
issn:
- 0261-1929
publication_status: epub_ahead
publisher: SAGE Publications
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Emerging bioethical conflicts: One Health and animal experimentation'
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: '21953'
abstract:
- lang: eng
text: Several Streptomyces strains were isolated from freshwater sediments collected
in the Laxenburg ponds (Lower Austria). Genome sequencing and bioinformatics analyses
revealed biosynthetic gene clusters (BGCs) that may specify production of chemically
diverse secondary metabolites. Various culture conditions were employed to induce
metabolite production, and subsequent LC-MS analyses facilitated the identification
of the produced compounds and their correlation with the corresponding BGCs. These
analyses of sediment-derived Streptomyces spp. highlight their extensive biosynthetic
potential, revealing a diverse range of bioactive secondary metabolites, including
siderophores, antibiotics, and other compounds with potential therapeutic applications.
Genomes of two Streptomyces isolates, one of them representing a potentially new
species, harbored several uncharacterized BGCs that may specify biosynthesis of
novel secondary metabolites. Although targeted overexpression of pathway-specific
regulators from these BGCs did not yield additional metabolites, whereas knockout
experiments led to metabolic changes, presumably reflecting regulatory or compensatory
interactions between multiple biosynthetic pathways. Continued exploration of
these strains and their BGCs may lead to the discovery of new bioactive molecules
with pharmaceutical and biotechnological applications.
acknowledgement: "The computational results of this work have been achieved using
the Life Science Compute Cluster (LiSC) of the University of Vienna. We additionally
thank Julia Ramesmayer for assistance during DNA extraction and sample preparation
for long-read sequencing. Support from the Mass Spectrometry Centre of the Faculty
of Chemistry, University of Vienna, is thankfully acknowledged.\r\nThe author(s)
declared that financial support was received for this work and/or its publication.
This work was supported by the University of Vienna via the Research Platform Secondary
Metabolomes of Bacterial Communities (MetaBac). Open access funding provided by
University of Vienna. "
article_number: '1793713'
article_processing_charge: Yes
article_type: original
author:
- first_name: Inmaculada
full_name: Tocino-Márquez, Inmaculada
last_name: Tocino-Márquez
- first_name: Martin
full_name: Zehl, Martin
id: 8e016d5b-5d77-11f0-86d2-96cdb3922a55
last_name: Zehl
orcid: 0000-0001-9685-0373
- first_name: Jovana
full_name: Batajic, Jovana
last_name: Batajic
- first_name: Joana
full_name: Séneca, Joana
last_name: Séneca
- first_name: Petra
full_name: Pjevac, Petra
last_name: Pjevac
- first_name: José
full_name: Murillo-Alba, José
last_name: Murillo-Alba
- first_name: Jesús
full_name: Martín, Jesús
last_name: Martín
- first_name: Olga N.
full_name: Sekurova, Olga N.
last_name: Sekurova
- first_name: Sergey B.
full_name: Zotchev, Sergey B.
last_name: Zotchev
citation:
ama: Tocino-Márquez I, Zehl M, Batajic J, et al. Unveiling the genomes and secondary
metabolomes of Streptomyces spp. from freshwater sediments. Frontiers in Microbiology.
2026;17. doi:10.3389/fmicb.2026.1793713
apa: Tocino-Márquez, I., Zehl, M., Batajic, J., Séneca, J., Pjevac, P., Murillo-Alba,
J., … Zotchev, S. B. (2026). Unveiling the genomes and secondary metabolomes of
Streptomyces spp. from freshwater sediments. Frontiers in Microbiology.
Frontiers Media. https://doi.org/10.3389/fmicb.2026.1793713
chicago: Tocino-Márquez, Inmaculada, Martin Zehl, Jovana Batajic, Joana Séneca,
Petra Pjevac, José Murillo-Alba, Jesús Martín, Olga N. Sekurova, and Sergey B.
Zotchev. “Unveiling the Genomes and Secondary Metabolomes of Streptomyces Spp.
from Freshwater Sediments.” Frontiers in Microbiology. Frontiers Media,
2026. https://doi.org/10.3389/fmicb.2026.1793713.
ieee: I. Tocino-Márquez et al., “Unveiling the genomes and secondary metabolomes
of Streptomyces spp. from freshwater sediments,” Frontiers in Microbiology,
vol. 17. Frontiers Media, 2026.
ista: Tocino-Márquez I, Zehl M, Batajic J, Séneca J, Pjevac P, Murillo-Alba J, Martín
J, Sekurova ON, Zotchev SB. 2026. Unveiling the genomes and secondary metabolomes
of Streptomyces spp. from freshwater sediments. Frontiers in Microbiology. 17,
1793713.
mla: Tocino-Márquez, Inmaculada, et al. “Unveiling the Genomes and Secondary Metabolomes
of Streptomyces Spp. from Freshwater Sediments.” Frontiers in Microbiology,
vol. 17, 1793713, Frontiers Media, 2026, doi:10.3389/fmicb.2026.1793713.
short: I. Tocino-Márquez, M. Zehl, J. Batajic, J. Séneca, P. Pjevac, J. Murillo-Alba,
J. Martín, O.N. Sekurova, S.B. Zotchev, Frontiers in Microbiology 17 (2026).
date_created: 2026-06-08T08:34:10Z
date_published: 2026-04-20T00:00:00Z
date_updated: 2026-06-10T07:49:04Z
day: '20'
ddc:
- '572'
department:
- _id: MassSpec
doi: 10.3389/fmicb.2026.1793713
external_id:
pmid:
- '42088272'
file:
- access_level: open_access
checksum: 31fb6b98c8a6d4007cb21808c6d2d9e3
content_type: application/pdf
creator: dernst
date_created: 2026-06-10T07:46:30Z
date_updated: 2026-06-10T07:46:30Z
file_id: '21989'
file_name: 2026_FrontiersMicrobiology_TocinoMarquez.pdf
file_size: 3582644
relation: main_file
success: 1
file_date_updated: 2026-06-10T07:46:30Z
has_accepted_license: '1'
intvolume: ' 17'
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
pmid: 1
publication: Frontiers in Microbiology
publication_identifier:
issn:
- 1664-302X
publication_status: published
publisher: Frontiers Media
quality_controlled: '1'
status: public
title: Unveiling the genomes and secondary metabolomes of Streptomyces spp. from freshwater
sediments
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: 17
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21954'
abstract:
- lang: eng
text: We investigate a framework for train-free MRI segmentation based on Topological
Data Analysis. The pipeline proceeds in three steps, first identifying the whole
object to segment via automatic thresholding, then detecting a distinctive subset
whose topology is known in advance, and finally deducing the various components
of the segmentation. A key ingredient is the extraction of approximate representative
cycles from persistence diagrams, which provides an interpretable link between
persistent features and anatomical components. To clarify the method’s scope,
we make the underlying topological and intensity assumptions explicit, quantify
when they hold on real data, and analyze typical failure modes. We evaluate the
approach on glioblastoma and on fetal cortical plate segmentation, with comparisons
to unsupervised and deep-learning references. By operating without large annotated
datasets, the method is well suited to scarce-data settings and provides an interpretable
baseline and practical initialization for expert refinement or learning-based
pipelines.
acknowledgement: Open access funding provided by Institute of Science and Technology
(IST Austria).
article_number: '20'
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Anton
full_name: François, Anton
last_name: François
- first_name: Raphaël
full_name: Tinarrage, Raphaël
id: 40ebcc9d-905f-11ef-bf0a-dc475da8a04e
last_name: Tinarrage
orcid: 0000-0002-1404-1095
citation:
ama: François A, Tinarrage R. Train-free segmentation in MRI with cubical persistent
homology. Journal of Mathematical Imaging and Vision. 2026;68(3). doi:10.1007/s10851-026-01300-1
apa: François, A., & Tinarrage, R. (2026). Train-free segmentation in MRI with
cubical persistent homology. Journal of Mathematical Imaging and Vision.
Springer Nature. https://doi.org/10.1007/s10851-026-01300-1
chicago: François, Anton, and Raphaël Tinarrage. “Train-Free Segmentation in MRI
with Cubical Persistent Homology.” Journal of Mathematical Imaging and Vision.
Springer Nature, 2026. https://doi.org/10.1007/s10851-026-01300-1.
ieee: A. François and R. Tinarrage, “Train-free segmentation in MRI with cubical
persistent homology,” Journal of Mathematical Imaging and Vision, vol.
68, no. 3. Springer Nature, 2026.
ista: François A, Tinarrage R. 2026. Train-free segmentation in MRI with cubical
persistent homology. Journal of Mathematical Imaging and Vision. 68(3), 20.
mla: François, Anton, and Raphaël Tinarrage. “Train-Free Segmentation in MRI with
Cubical Persistent Homology.” Journal of Mathematical Imaging and Vision,
vol. 68, no. 3, 20, Springer Nature, 2026, doi:10.1007/s10851-026-01300-1.
short: A. François, R. Tinarrage, Journal of Mathematical Imaging and Vision 68
(2026).
corr_author: '1'
date_created: 2026-06-08T08:34:43Z
date_published: 2026-05-25T00:00:00Z
date_updated: 2026-06-10T08:00:52Z
day: '25'
ddc:
- '510'
department:
- _id: UlWa
doi: 10.1007/s10851-026-01300-1
external_id:
arxiv:
- '2401.01160'
file:
- access_level: open_access
checksum: 34080653e0f9c6160856a6bbca9b5248
content_type: application/pdf
creator: dernst
date_created: 2026-06-10T07:58:58Z
date_updated: 2026-06-10T07:58:58Z
file_id: '21990'
file_name: 2026_JourMathImaging_Francois.pdf
file_size: 6070434
relation: main_file
success: 1
file_date_updated: 2026-06-10T07:58:58Z
has_accepted_license: '1'
intvolume: ' 68'
issue: '3'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
publication: Journal of Mathematical Imaging and Vision
publication_identifier:
eissn:
- 1573-7683
issn:
- 0924-9907
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Train-free segmentation in MRI with cubical persistent homology
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: 68
year: '2026'
...
---
_id: '21145'
abstract:
- lang: eng
text: 'Protein conformational energy landscapes are shaped not only by intramolecular
interactions but also by their environment. In protein crystals and protein-protein
complexes, intermolecular contacts alter this energy landscape, but the exact
nature of this alteration is difficult to decipher. Understanding how the crystal
lattice affects protein dynamics is crucial for crystallography-based studies
of motion, yet its influence on collective motions remains unclear. Aromatic ring
flips in the hydrophobic core represent sensitive probes of such dynamics. Here,
we compare the kinetics of aromatic ring flips in the protein GB1 in crystals,
in complex with its binding partner IgG, and in solution, combining advanced isotope
labeling with quantitative NMR methods. We show that rings in the core flip nearly
a thousand times less frequently in crystals than in solution. Enhanced-sampling
molecular dynamics simulations, based on a new crystal structure, reproduce these
elevated barriers and reveal how the crystal restrains motions. '
acknowledged_ssus:
- _id: NMR
- _id: LifeSc
acknowledgement: "We thank Nikolai R. Skrynnikov and Olga O. Lebedenko (St. Petersburg)
for insightful discussions and for performing exploratory MD simulations. We are
grateful to Tobias Schubeis (Lyon) for advice with GB1 crystallization, and Rebecca
Schmid for initial crystallization trials.\r\nWe thank Sebastian Falkner for assistance
with constructing the structural model of the IgG:GB1 complex.\r\nThis research
was supported by the Scientific Service Units (SSU) of Institute of Science and
Technology Austria (ISTA) through resources provided by the Nuclear Magnetic Resonance
and the Lab Support Facilities. We thank Petra Rovó and Margarita Valhondo Falcón
for excellent support of the NMR facility.\r\nLea M. Becker is recipient of a DOC
fellowship of the Austrian Academy of Sciences at the Institute of Science and Technology
Austria (grant no. PR10660EAW01). Christophe Chipot acknowledges the European Research
Council (grant project 101097272 ``MilliInMicro'') and the Métropole du Grand Nancy
(grant project ``ARC''). BM07-FIP2 is supported by the French ANR PIA3 (France 2030)
EquipEx+ project MAGNIFIX under grant agreement ANR-21-ESRE-0011."
article_processing_charge: No
author:
- first_name: Lea Marie
full_name: Becker, Lea Marie
id: 36336939-eb97-11eb-a6c2-c83f1214ca79
last_name: Becker
orcid: 0000-0002-6401-5151
- first_name: Paul
full_name: Schanda, Paul
id: 7B541462-FAF6-11E9-A490-E8DFE5697425
last_name: Schanda
orcid: 0000-0002-9350-7606
- first_name: Christophe
full_name: Chipot, Christophe
last_name: Chipot
citation:
ama: Becker LM, Schanda P, Chipot C. Additional Data for “Aromatic Ring Flips Reveal
Reshaping of Protein Dynamics in Crystals and Complexes.” 2026. doi:10.15479/AT-ISTA-21145
apa: Becker, L. M., Schanda, P., & Chipot, C. (2026). Additional Data for “Aromatic
Ring Flips Reveal Reshaping of Protein Dynamics in Crystals and Complexes.” Institute
of Science and Technology Austria. https://doi.org/10.15479/AT-ISTA-21145
chicago: Becker, Lea Marie, Paul Schanda, and Christophe Chipot. “Additional Data
for ‘Aromatic Ring Flips Reveal Reshaping of Protein Dynamics in Crystals and
Complexes.’” Institute of Science and Technology Austria, 2026. https://doi.org/10.15479/AT-ISTA-21145.
ieee: L. M. Becker, P. Schanda, and C. Chipot, “Additional Data for ‘Aromatic Ring
Flips Reveal Reshaping of Protein Dynamics in Crystals and Complexes.’” Institute
of Science and Technology Austria, 2026.
ista: Becker LM, Schanda P, Chipot C. 2026. Additional Data for ‘Aromatic Ring Flips
Reveal Reshaping of Protein Dynamics in Crystals and Complexes’, Institute of
Science and Technology Austria, 10.15479/AT-ISTA-21145.
mla: Becker, Lea Marie, et al. Additional Data for “Aromatic Ring Flips Reveal
Reshaping of Protein Dynamics in Crystals and Complexes.” Institute of Science
and Technology Austria, 2026, doi:10.15479/AT-ISTA-21145.
short: L.M. Becker, P. Schanda, C. Chipot, (2026).
contributor:
- contributor_type: researcher
first_name: Haohao
last_name: Fu
- contributor_type: researcher
first_name: Benjamin
id: 71cda2f3-e604-11ee-a1df-da10587eda3f
last_name: Tatman
- contributor_type: researcher
first_name: Matthias
last_name: Dreydoppel
- contributor_type: researcher
first_name: Anna
id: 9fb2a840-89e1-11ee-a8b7-cc5c7ba62471
last_name: Kapitonova
- contributor_type: researcher
first_name: Daniel
id: 302BADF6-85FC-11EA-9E3B-B9493DDC885E
last_name: Balazs
orcid: 0000-0001-7597-043X
- contributor_type: researcher
first_name: Ulrich
last_name: Weininger
- contributor_type: researcher
first_name: Sylvain
last_name: Engilberge
corr_author: '1'
date_created: 2026-02-05T13:54:39Z
date_published: 2026-02-09T00:00:00Z
date_updated: 2026-06-10T08:25:16Z
day: '09'
ddc:
- '572'
department:
- _id: GradSch
- _id: PaSc
doi: 10.15479/AT-ISTA-21145
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date_updated: 2026-02-05T13:52:37Z
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date_created: 2026-02-05T13:52:41Z
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month: '02'
oa: 1
oa_version: Published Version
project:
- _id: 7be609c4-9f16-11ee-852c-85015ce2b9b0
grant_number: '26777'
name: Exploring protein dynamics by solid-state MAS NMR through specific labeling
approaches
publisher: Institute of Science and Technology Austria
related_material:
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relation: earlier_version
status: public
status: public
title: Additional Data for "Aromatic Ring Flips Reveal Reshaping of Protein Dynamics
in Crystals and Complexes"
tmp:
image: /images/cc_by_nc.png
legal_code_url: https://creativecommons.org/licenses/by-nc/4.0/legalcode
name: Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
short: CC BY-NC (4.0)
type: research_data
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '20840'
abstract:
- lang: eng
text: Probing the possibility of entanglement generation through gravity offers
a path to tackle the question of whether gravitational fields possess a quantum
mechanical nature. A potential realization necessitates systems with low-frequency
dynamics at an optimal mass scale, for which the microgram-to-milligram range
is a strong contender. Here, after refining a figure-of-merit for the problem,
we present a 1-milligram torsional pendulum operating at 18 Hz. We demonstrate
laser cooling its motion from room temperature to 240 microkelvins, surpassing
by over 20-fold the coldest motions attained for oscillators ranging from micrograms
to kilograms. We quantify and contrast the utility of the current approach with
other platforms. The achieved performance and large improvement potential highlight
milligram-scale torsional pendulums as a powerful platform for precision measurements
relevant to future studies at the quantum-gravity interface.
acknowledgement: We thank Gerard Higgins, Andrei Militaru, Nikolai Kiesel, and Markus
Aspelmeyer for useful discussions on the topic of the figure-of-merit. We thank
Teodor Strömberg for helping with the additional characterizations of the optical
lever noise. We thank Johannes Fink and Scott Waitukaitis for their helpful feedback
on the manuscript. This work was supported by Institute of Science and Technology
Austria and the European Research Council under Grant No. 101087907 (ERC CoG QuHAMP).
article_number: '80'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Sofya
full_name: Agafonova, Sofya
id: 09501ff6-dca7-11ea-a8ae-b3e0b9166e80
last_name: Agafonova
orcid: 0000-0003-0582-2946
- first_name: Pere
full_name: Rosello, Pere
last_name: Rosello
- first_name: Manuel
full_name: Mekonnen, Manuel
last_name: Mekonnen
- first_name: Onur
full_name: Hosten, Onur
id: 4C02D85E-F248-11E8-B48F-1D18A9856A87
last_name: Hosten
orcid: 0000-0002-2031-204X
citation:
ama: Agafonova S, Rosello P, Mekonnen M, Hosten O. One-milligram torsional pendulum
toward experiments at the quantum-gravity interface. Communications Physics.
2026;9. doi:10.1038/s42005-026-02514-w
apa: Agafonova, S., Rosello, P., Mekonnen, M., & Hosten, O. (2026). One-milligram
torsional pendulum toward experiments at the quantum-gravity interface. Communications
Physics. Springer Nature. https://doi.org/10.1038/s42005-026-02514-w
chicago: Agafonova, Sofia, Pere Rosello, Manuel Mekonnen, and Onur Hosten. “One-Milligram
Torsional Pendulum toward Experiments at the Quantum-Gravity Interface.” Communications
Physics. Springer Nature, 2026. https://doi.org/10.1038/s42005-026-02514-w.
ieee: S. Agafonova, P. Rosello, M. Mekonnen, and O. Hosten, “One-milligram torsional
pendulum toward experiments at the quantum-gravity interface,” Communications
Physics, vol. 9. Springer Nature, 2026.
ista: Agafonova S, Rosello P, Mekonnen M, Hosten O. 2026. One-milligram torsional
pendulum toward experiments at the quantum-gravity interface. Communications Physics.
9, 80.
mla: Agafonova, Sofia, et al. “One-Milligram Torsional Pendulum toward Experiments
at the Quantum-Gravity Interface.” Communications Physics, vol. 9, 80,
Springer Nature, 2026, doi:10.1038/s42005-026-02514-w.
short: S. Agafonova, P. Rosello, M. Mekonnen, O. Hosten, Communications Physics
9 (2026).
corr_author: '1'
date_created: 2025-12-21T11:39:04Z
date_published: 2026-03-04T00:00:00Z
date_updated: 2026-06-10T08:36:06Z
day: '04'
ddc:
- '530'
department:
- _id: GradSch
- _id: OnHo
doi: 10.1038/s42005-026-02514-w
external_id:
arxiv:
- '2408.09445'
file:
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checksum: 62e2175e7e3ad49260ae6a7b4e0860a2
content_type: application/pdf
creator: dernst
date_created: 2026-03-16T10:07:46Z
date_updated: 2026-03-16T10:07:46Z
file_id: '21457'
file_name: 2026_CommunicationsPhysics_Agafonova.pdf
file_size: 1901772
relation: main_file
success: 1
file_date_updated: 2026-03-16T10:07:46Z
has_accepted_license: '1'
intvolume: ' 9'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
project:
- _id: bdb2a702-d553-11ed-ba76-f12e3e5a3bc6
grant_number: '101087907'
name: 'A quantum hybrid of atoms and milligram-scale pendulums: towards gravitational
quantum mechanics'
publication: Communications Physics
publication_identifier:
eissn:
- 2399-3650
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
record:
- id: '20842'
relation: research_data
status: public
scopus_import: '1'
status: public
title: One-milligram torsional pendulum toward experiments at the quantum-gravity
interface
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: repository
OA_type: free access
_id: '21284'
abstract:
- lang: eng
text: The advantageous characteristics attributed to the 19F nucleus have made it
a popular target for NMR once again in recent years. Aside from solution NMR,
an increasing number of studies have been conducted applying solid-state magic-angle-spinning
NMR to fluorine-labeled samples. Here, the high chemical shift anisotropy and
strong dipolar couplings can be utilized to get structural insights into proteins
and measure long distances. Despite increasing popularity and promising benefits,
the sensitivity of biomolecular 19F MAS NMR often suffers from slow longitudinal
T1 relaxation and therefore long recycle delays. In this work, we expand paramagnetic
doping, an approach commonly used to reduce proton T1 relaxation times, to 19F-labeled
biological samples. We study the effect of Gd(DTPA) and Gd(DTPA-BMA) on 19F and
13C T1 and T2 relaxation in a [5-19F13C]-tryptophan-labeled protein via 19F-detected
MAS NMR experiments. The observed paramagnetic relaxation enhancement substantially
reduces measurement times of 19F MAS NMR experiments without compromising resolution.
Additionally, we report the chemical-shift assignments of all four fluorotryptophan
signals in the 12 × 39 kDa large protein using a mutagenesis approach.
acknowledged_ssus:
- _id: NMR
- _id: LifeSc
acknowledgement: We thank Ben P. Tatman for insightful discussions. This research
was supported by the Scientific Service Units (SSU) of Institute of Science and
Technology Austria (ISTA) through resources provided by the Nuclear Magnetic Resonance
Facility and the Lab Support Facility.
article_processing_charge: No
author:
- first_name: Lea Marie
full_name: Becker, Lea Marie
id: 36336939-eb97-11eb-a6c2-c83f1214ca79
last_name: Becker
orcid: 0000-0002-6401-5151
- first_name: Paul
full_name: Schanda, Paul
id: 7B541462-FAF6-11E9-A490-E8DFE5697425
last_name: Schanda
orcid: 0000-0002-9350-7606
citation:
ama: Becker LM, Schanda P. Research data for “Accelerated 19F biomolecular magic-angle
spinning NMR with paramagnetic dopants.” 2026. doi:10.15479/AT-ISTA-21284
apa: Becker, L. M., & Schanda, P. (2026). Research data for “Accelerated 19F
biomolecular magic-angle spinning NMR with paramagnetic dopants.” Institute of
Science and Technology Austria. https://doi.org/10.15479/AT-ISTA-21284
chicago: Becker, Lea Marie, and Paul Schanda. “Research Data for ‘Accelerated 19F
Biomolecular Magic-Angle Spinning NMR with Paramagnetic Dopants.’” Institute of
Science and Technology Austria, 2026. https://doi.org/10.15479/AT-ISTA-21284.
ieee: L. M. Becker and P. Schanda, “Research data for ‘Accelerated 19F biomolecular
magic-angle spinning NMR with paramagnetic dopants.’” Institute of Science and
Technology Austria, 2026.
ista: Becker LM, Schanda P. 2026. Research data for ‘Accelerated 19F biomolecular
magic-angle spinning NMR with paramagnetic dopants’, Institute of Science and
Technology Austria, 10.15479/AT-ISTA-21284.
mla: Becker, Lea Marie, and Paul Schanda. Research Data for “Accelerated 19F
Biomolecular Magic-Angle Spinning NMR with Paramagnetic Dopants.” Institute
of Science and Technology Austria, 2026, doi:10.15479/AT-ISTA-21284.
short: L.M. Becker, P. Schanda, (2026).
contributor:
- contributor_type: researcher
first_name: Giorgia
id: 334a5e40-8747-11f0-b671-ba1f5154b4b4
last_name: Toscano
- contributor_type: researcher
first_name: Anna
id: 9fb2a840-89e1-11ee-a8b7-cc5c7ba62471
last_name: Kapitonova
- contributor_type: researcher
first_name: Rajkumar
id: a3089acd-6806-11ee-bacc-f0c7d500ad20
last_name: Singh
- contributor_type: researcher
first_name: Undina
id: bb74f472-ae54-11eb-9835-bc9c22fb1183
last_name: Guillerm
- contributor_type: researcher
first_name: Roman
last_name: Lichtenecker
corr_author: '1'
date_created: 2026-02-17T10:17:14Z
date_published: 2026-02-18T00:00:00Z
date_updated: 2026-06-10T09:28:41Z
day: '18'
ddc:
- '541'
department:
- _id: GradSch
- _id: PaSc
doi: 10.15479/AT-ISTA-21284
file:
- access_level: open_access
checksum: 2d3105f26be578073b88ee1f2ea0bdb1
content_type: application/zip
creator: lbecker
date_created: 2026-02-17T10:11:14Z
date_updated: 2026-02-17T10:11:14Z
file_id: '21285'
file_name: Research_data.zip
file_size: 36996027
relation: main_file
success: 1
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checksum: e24aebcdb8856cb181cbaa02de020ddb
content_type: text/plain
creator: lbecker
date_created: 2026-02-17T10:11:14Z
date_updated: 2026-02-17T10:11:14Z
file_id: '21286'
file_name: README.txt
file_size: 1993
relation: table_of_contents
file_date_updated: 2026-02-17T10:11:14Z
has_accepted_license: '1'
month: '2'
oa: 1
oa_version: Published Version
publisher: Institute of Science and Technology Austria
status: public
title: Research data for "Accelerated 19F biomolecular magic-angle spinning NMR with
paramagnetic dopants"
tmp:
image: /images/cc_by_nc.png
legal_code_url: https://creativecommons.org/licenses/by-nc/4.0/legalcode
name: Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
short: CC BY-NC (4.0)
type: research_data
user_id: 68b8ca59-c5b3-11ee-8790-cd641c68093d
year: '2026'
...