Showing 1–50 of 188 results for author: Rafelski, M

COS2035: Extending COS/FUV Operations Through the 2030s

Authors: Marc Rafelski, David Sahnow, Christian I. Johnson, Bethan James, Svea Hernandez, John Debes, Beverly Serrano, Kate Davis, Serge Dieterich, Van Dixon, Leonardo Dos Santos, Travis Fischer, Elaine Frazer, David French, Mark Giuliano, Joshua Goldberg, Sten Hasselquist, Jacqueline Hernandez, Nick Indriolo, Mike Kelly, Olivia Lupie, Lauren Miller, Diego Mundo, Anna Payne, Karla Peterson , et al. (7 additional authors not shown)

Abstract: The far-ultraviolet (FUV) detector of the Cosmic Origins Spectrograph (COS) accumulates gain sag where photons land, and without continued mitigation this degradation would render the most used modes unusable. To extend COS FUV operations through the 2030s, the COS team developed the COS2035 strategy, which builds on the existing COS2025 rules with four technical breakthroughs and two new usage po… ▽ More The far-ultraviolet (FUV) detector of the Cosmic Origins Spectrograph (COS) accumulates gain sag where photons land, and without continued mitigation this degradation would render the most used modes unusable. To extend COS FUV operations through the 2030s, the COS team developed the COS2035 strategy, which builds on the existing COS2025 rules with four technical breakthroughs and two new usage policies. First, SPLIT-wavecals decouple wavelength calibration from science exposures and open detector real estate above the Pt-Ne lamp light leak. Second, a hybrid lifetime position (LP) architecture allows different gratings to operate at different LPs simultaneously. Third, the LP-infinity framework removes the dependence on the eight-LP limit in the COS flight software, supported by a new table-based APT and TRANS rules architecture. Fourth, a revised gain-sag flagging method evaluates integrated column count loss against the maximum achievable signal-to-noise (S/N) per mode. The two new usage policies cap per-target S/N at the maximum achievable value set by fixed-pattern noise, and limit any single program to 2\% of the lifetime at any single LP. With LP7 and LP10 enabled in Cycle 33 and LP11 and LP12 in active commissioning for Cycles 34 and 35, the COS2035 strategy positions the FUV channel for continued high productivity through the 2030s. △ Less

Submitted 15 July, 2026; originally announced July 2026.

Comments: 23 pages, 5 figures

Report number: Instrument Science Report COS 2026-04

Spatially Resolved Nebular-Stellar Reddening with JWST/NIRISS

Authors: Peter J. Watson, Benedetta Vulcani, Tommaso Treu, Ayan Acharyya, Marc Rafelski, Anahita Alavi, Matthew Hayes, Keunho Kim, Faezeh Manesh, Claudia Scarlata

Abstract: An accurate determination of the dust attenuation within galaxies is essential to derive key physical properties such as the star formation rate (SFR). We present an analysis using the JWST/NIRISS data from the GLASS-JWST ERS programme to investigate and characterise the stellar and nebular reddening of galaxies at $1.0<z<2.4$, down to the sub-kpc scale. We use a multiregion fitting method to extr… ▽ More An accurate determination of the dust attenuation within galaxies is essential to derive key physical properties such as the star formation rate (SFR). We present an analysis using the JWST/NIRISS data from the GLASS-JWST ERS programme to investigate and characterise the stellar and nebular reddening of galaxies at $1.0<z<2.4$, down to the sub-kpc scale. We use a multiregion fitting method to extract high-quality H$α$ and H$β$ emission line maps for 99 individual galaxies across a stellar mass range $7.0<\log_{10}(M_*/\mathrm{M}_{\odot})<10.5$. We find no evidence for ratios of the Balmer decrement (H$α$/H$β$) below the intrinsic limit for Case B recombination, beyond the expected variation from observational uncertainties. We reproduce the local correlation between the Balmer decrement and total stellar mass, and find no measurable difference when splitting the sample by redshift, with negligible attenuation below $\log_{10}(M_*/\mathrm{M}_{\odot})\lesssim8.5$. Similarly, the best-fit relation between the nebular and continuum reddening follows the same relation as in local starburst galaxies, $E(B-V)_{\mathrm{SED}} = (0.46\pm0.02)E(B-V)_{\mathrm{neb}}$, together indicating no significant evolution in the dust geometry within galaxies out to $z\lesssim2.4$. We derive best-fit linear relations between the differential nebular-stellar reddening and the SED-derived star formation rate (SFR) and stellar mass, finding statistically significant relations for both quantities. We use our spatially-resolved measurements to derive an empirical calibration between the resolved differential reddening, and the SFR surface density. These will enable crucial dust attenuation corrections for spatially-resolved science at higher redshifts where the Balmer lines are inaccessible, such as with future Roman grism observations. △ Less

Submitted 10 June, 2026; originally announced June 2026.

Comments: 17 pages, 19 figures (including appendices), submitted to A&A

The Hubble Advanced Spectral Product (HASP) Program

Authors: John Debes, Ravi Sankrit, Travis Fischer, Elaine Frazer, Alec Hirschauer, Kate Rowlands, Matthew Burger, Robert Swaters, Robert Jedrzejewski, Sierra Gomez, Leonardo Dos Santos, Svea Hernandez, Lauren Miller, Anna Payne, Marc Rafelski, Thomas Wevers, Sara Anderson, Tom Bair, Kathryn Bello, Joleen Carlberg, Brian Charlow, Andrew Cortese, Nadia Dencheva, Tracy Ellis, Ben Falk , et al. (17 additional authors not shown)

Abstract: The Hubble Advanced Spectral Products (HASP) program is designed to robustly coadd Cosmic Origins Spectrograph (COS) and Space Telescope Imaging Spectrograph (STIS) spectra within the Mikulski Archive for Space Telescopes (MAST) in an automated fashion such that coadds are available for new data or archival data with updated calibrations. For each target within a visit or program, HASP employs a m… ▽ More The Hubble Advanced Spectral Products (HASP) program is designed to robustly coadd Cosmic Origins Spectrograph (COS) and Space Telescope Imaging Spectrograph (STIS) spectra within the Mikulski Archive for Space Telescopes (MAST) in an automated fashion such that coadds are available for new data or archival data with updated calibrations. For each target within a visit or program, HASP employs a meticulous multi-stage filtering process to ensure data quality and creates coadded products for all central wavelengths (CENWAVEs) within specific gratings, as well as combined products using different gratings and instruments. The project also emphasizes making the code accessible to the user community for custom coaddition. As calibrations improve and new data are added to the archive, HASP products are re-created automatically so that they represent the best reduction of a given visit or program. Automated coadditions like those achieved by HASP can significantly enhance the combination of different CENWAVES, increase signal-to-noise ratios, and increase wavelength coverage. These properties make HASP a vital resource for astronomers using archival spectroscopic data from HST. △ Less

Submitted 7 May, 2026; originally announced May 2026.

Comments: 30 pages, 8 figures

Report number: Instrument Science Report COS 2024-01

Overview of the New Hubble Spectroscopic Legacy Archive

Authors: Ravi Sankrit, John Debes, Matthew Burger, Van Dixon, Anna Payne, Leonardo Dos Santos, Thomas Wevers, Travis Fischer, Peter Forshay, Svea Hernandez, Robert Jedrzejewski, Rich Kidwell, Lauren Miller, Marc Rafelski, David Rodriguez, Robert Swaters, Dan Welty, Sara Anderson, Thomas Bair, Joleen Carlberg, Brian Charlow, Andrew Cortese, Tracy Ellis, Ben Falk, Scott Fleming , et al. (12 additional authors not shown)

Abstract: The new Hubble Spectroscopic Legacy Archive (HSLA) provides coadded spectra of individual targets that have been observed with the Cosmic Origins Spectrograph (COS) and the Space Telescope Imaging Spectrograph (STIS) over their operating lifetime. HSLA uses data available in the Mikulski Archive for Space Telescopes (MAST). It automatically produces coadds whenever new data become publicly availab… ▽ More The new Hubble Spectroscopic Legacy Archive (HSLA) provides coadded spectra of individual targets that have been observed with the Cosmic Origins Spectrograph (COS) and the Space Telescope Imaging Spectrograph (STIS) over their operating lifetime. HSLA uses data available in the Mikulski Archive for Space Telescopes (MAST). It automatically produces coadds whenever new data become publicly available or when there is newly recalibrated data. HSLA defines individual targets by their associated coordinates, accounting for proper motions, and uses SIMBAD, NED and the Phase II observing proposals to obtain astronomical classifications for each object. Coadded spectra are produced for each observing mode. In the case of COS far-ultraviolet observations there is one coadded spectrum for each lifetime position (LP). Additionally, a spectrum spanning the entire wavelength range covered by the observations is produced by abutting the spectra from a selection of individual modes. For each individual target, HSLA also provides a human-readable metadata file with key information that can be used in searches or for further exploration of the data. The HSLA project also makes the code used for coadding spectra publicly available along with several other tools (using Jupyter notebooks) for custom coaddition required in special cases. In this report we will describe the main components of HSLA and provide a brief description of how the data and metadata can be accessed. △ Less

Submitted 5 May, 2026; originally announced May 2026.

Comments: 35 pages, 10 figures

Report number: Instrument Science Report COS 2025-18

A Comprehensive Study of Morphology and Kinematics in Extended Nebulae Around UV Luminous Quasars at $z\approx1$

Authors: Zhuoqi Liu, Sean D. Johnson, Eric F. Bell, Zhijie Qu, Benoît Epinat, Hsiao-Wen Chen, Marc Rafelski, Jennifer I-Hsiu Li, Alexander Beckett, Mandy C. Chen, Sayak Dutta, David DePalma, Gwen C. Rudie, Joop Schaye, Patrick Petitjean, Sebastiano Cantalupo, Elise Fuller, Wolfram Kollatschny, Sebastián López, Nishant Mishra, Sowgat Muzahid, Andrea Travascio, Fakhri S. Zahedy

Abstract: Gas flows between galaxies and the circumgalactic medium (CGM) play a central role in galaxy evolution and can become observable as giant nebulae when illuminated by the quasars. We present an ensemble study of nebulae around 30 UV-luminous quasars at z=0.4-1.4 from the CUBS and MUSEQuBES surveys, 27 of which are detected in extended [O II] and/or [O III] emission. Based on a joint analysis of neb… ▽ More Gas flows between galaxies and the circumgalactic medium (CGM) play a central role in galaxy evolution and can become observable as giant nebulae when illuminated by the quasars. We present an ensemble study of nebulae around 30 UV-luminous quasars at z=0.4-1.4 from the CUBS and MUSEQuBES surveys, 27 of which are detected in extended [O II] and/or [O III] emission. Based on a joint analysis of nebular morphology and surrounding galaxy environments, we introduce three morpho-kinematic classifications. We identify eleven irregular, large-scale (>50 kpc) systems, many of which are likely interaction-related; twelve compact host-galaxy-scale nebula, likely tracing CGM/ISM gas; and four systems with complex morphologies of uncertain origin. We introduce a quantitative measure of the spatial and kinematic association between nebulae and quasar-host group galaxies, finding a statistically significant association for ten nebulae, most of which are irregular, large-scale nebulae, consistent with qualitative analysis. Radio jets are detected in six systems, with no strong correlation found between radio activity and nebular emission. The [O II] nebulae are more asymmetric than their Ly$α$ counterparts at $z>2$, but bear more similarity to H I gas observed in 21 cm around local elliptical galaxies. Blueshifted-redshifted patterns, likely tracing gas rotation, are observed in roughly 30% of the systems, though disturbed kinematics suggest that feedback may also be important. These results show that giant quasar nebulae are not a uniform class of objects, but instead arise through multiple pathways shaped by host-galaxy gas, galaxy interactions, group environments, and quasar activity, with the most striking cases associated with galaxy interactions. △ Less

Submitted 4 August, 2026; v1 submitted 3 May, 2026; originally announced May 2026.

Comments: Accepted by ApJ; 28 pages, 9 figures

Validating z > 7.5 Lyman Break Galaxy candidates in the COSMOS field with JWST/PASSAGE

Authors: Zoke W. Sackih, Mason S. Huberty, Claudia Scarlata, Peter J. Watson, Andrew J. Battisti, Farhanul Hasan, Matthew J. Hayes, Matthew A. Malkan, Vihang Mehta, Kalina V. Nedkova, Marc Rafelski, Benedetta Vulcani

Abstract: We analyze spectroscopy from one NIRISS pointing in the JWST-PASSAGE program for seven candidate $z \gtrsim 7.5$ photometrically-selected COSMOS-Web sources. We spectroscopically confirm one out of seven sources as a Lyman break galaxy (LBG) at $z=7.962^{+0.003}_{-0.006}$, with $m_{F150W} = 25.9$ (AB). The remaining sources are too faint in the continuum (i.e., $m_{F150W} \gtrsim 26$ AB) to provid… ▽ More We analyze spectroscopy from one NIRISS pointing in the JWST-PASSAGE program for seven candidate $z \gtrsim 7.5$ photometrically-selected COSMOS-Web sources. We spectroscopically confirm one out of seven sources as a Lyman break galaxy (LBG) at $z=7.962^{+0.003}_{-0.006}$, with $m_{F150W} = 25.9$ (AB). The remaining sources are too faint in the continuum (i.e., $m_{F150W} \gtrsim 26$ AB) to provide a redshift measurement from the Lyman break, and do not show emission lines in their spectra. Although this study contains only one spectroscopically confirmed source, the confirmation of a luminous $z \sim 8$ galaxy within this $\sim4.8$ arcmin$^2$ field implies a surface density of $\sim 0.21^{+0.59}_{-0.17}$ arcmin$^{-2}$, $\approx 10\times$ higher than inferred from wide-area photometric surveys, suggesting a potential overdensity at $z\sim8$ in the COSMOS field. △ Less

Submitted 24 May, 2026; v1 submitted 1 May, 2026; originally announced May 2026.

Comments: Accepted by RNAAS, 3 pages, 1 figure

BEACON: JWST NIRCam Pure-parallel Imaging Survey. III. Constraints on the UV LF and the Clustering of z~7-14 Galaxies

Authors: Kimi C. Kreilgaard, Charlotte A. Mason, Takahiro Morishita, Yechi Zhang, Viola Gelli, Nicha Leethochawalit, Tommaso Treu, Michele Trenti, Abdurro'uf, Hakim Atek, Maruša Bradač, Larry D. Bradley, Andrew J. Bunker, Novan Saputra Haryana, Matthew J. Hayes, Zhaoran Liu, Vihang Mehta, Marc Rafelski, Guido Roberts-Borsani, Claudia Scarlata, Massimo Stiavelli, Ryo A. Sutanto, Kosuke Takahashi, Benedetta Vulcani

Abstract: The James Webb Space Telescope (JWST) has extended the frontier of galaxy detection to redshifts z>11, finding a high abundance of UV-bright sources that challenge theoretical models. However, most current results come from just a few fields, introducing uncertainties due to cosmic variance. Here, we constrain z~7-14 UV luminosity functions (LFs) over ~400 sq. arcmin across 36 independent sightlin… ▽ More The James Webb Space Telescope (JWST) has extended the frontier of galaxy detection to redshifts z>11, finding a high abundance of UV-bright sources that challenge theoretical models. However, most current results come from just a few fields, introducing uncertainties due to cosmic variance. Here, we constrain z~7-14 UV luminosity functions (LFs) over ~400 sq. arcmin across 36 independent sightlines from DR2 of BEACON, a JWST pure-parallel NIRCam multi-band imaging survey. We identify 164 7<z<12 galaxy candidates: 150 F090W-, 14 F115W-, and no robust F150W-dropouts. In the 11 pointings overlapping with public JWST spectroscopy, we find no contaminants, indicating a high purity in our sample. Our z~7.5 UV LF agrees with previous bright-end measurements but yields lower number densities at -21 < Muv < -19. At z~10, our measurements are lower than most photometric JWST results but match spectroscopic constraints, consistent with the high purity of our selection. The LFs at z~7.5 and z~10 are consistent with pre-JWST models, while our limits at z>13 do not rule out a possible excess. We measure significant clustering of bright (Muv<-20.5) galaxies at 7<z<10. Fields hosting such sources are approximately three times more likely to be overdense relative to the full survey, implying that UV-bright galaxies preferentially reside in the most massive halos at these redshifts. Comparing with semi-numerical simulations, we estimate that Muv < -20.5 galaxies inhabit halos ~0.8 dex less massive at z~11 than at z~8, consistent with a shift to higher star formation rates. However, their observed clustering exceeds predictions from pre-JWST luminosity-halo mass relations, suggesting these sources reside in more massive halos than previously modelled and/or multiple halo occupation. △ Less

Submitted 6 August, 2026; v1 submitted 20 April, 2026; originally announced April 2026.

Comments: 33 pages, 11 figures, accepted to ApJ

The Qz5 Survey (II): Metallicity Evolution of Damped Lyα Systems Out to z$\sim$5

Authors: Marie Wisz, Marc Rafelski, Grecco Oyarzun, Regina Jorgenson, Michele Fumagalli, Marcel Neeleman, Xavier Prochaska, Lise Christensen, Eldon Fobbs, George Becker, Joseph Hennawi, Gabor Worseck, Sebastian Lopez

Abstract: Damped Ly$α$ absorbers (DLAs) are the highest \HI\ column density (\NHI) absorption line systems detected in the spectra of background quasars. DLAs dominate the neutral gas content of the Universe ($Ω_{\rm HI}$) and are used to measure the metallicity evolution of \HI\ gas. In this work, we introduce a sample of five recently detected DLAs at $z > 4.7$, found in mid to high-resolution spectroscop… ▽ More Damped Ly$α$ absorbers (DLAs) are the highest \HI\ column density (\NHI) absorption line systems detected in the spectra of background quasars. DLAs dominate the neutral gas content of the Universe ($Ω_{\rm HI}$) and are used to measure the metallicity evolution of \HI\ gas. In this work, we introduce a sample of five recently detected DLAs at $z > 4.7$, found in mid to high-resolution spectroscopy from VLT/X-shooter and Keck/HIRES. These DLAs were not pre-selected based on metallicity, enabling an unbiased study of the metallicity of HI gas at $z \sim 5$. We also search for DLAs unbiased in metallicity at $0<z<5.5$ from the literature, we apply a combined correction for dust depletion and $α$-enhancement (assuming no depletion of S, Si, and Zn) to Fe abundances, and we measure the cosmic metallicity evolution of $α$-elements using a linear fit with a slope of$-0.22 \pm 0.05$ dex per unit redshift. For the highest redshift bin, we find an \NHI weighted average of $\langle Z \rangle = -2.00$. This value is $4.4σ$ deviant from the trend recovered at $z < 4.7$ and a K-S test comparison gives a $2.4 σ$ difference. We conclude that the metallicity of HI gas sharply decreases at $z \sim 5$, in agreement with previous tentative evidence. This sharp decrease may be connected with the onset of the enrichment of galaxies' circumgalactic media or with the end of cosmic reionization, though we cannot exclude that it is driven by small sample statistics. △ Less

Submitted 17 April, 2026; originally announced April 2026.

Comments: 32 pages, 10 figures, 1 table, 3 appendices; accepted to ApJ 16 April 2026

The Great Escape of ionizing photons during Cosmic Morning

Authors: Kanak Saha, Roland Bacon, Anne Verhamme, Soumil Maulick, Akio Inoue, Souradeep Bhattacharya, Marc Rafelski, Edmund Christian Herenz, Rogier Windhorst, Michael Rutkowski, Shyam N. Tandon

Abstract: The end of the Cosmic Dark Age marked the onset of reionization, driven by extreme-UV photons from the first galaxies. Direct detection of such photons has remained challenging due to strong intergalactic attenuation. Here, we report the first direct detection of ionizing photons at rest-frame wavelengths $350Å$, $392Å$, and $485Å$, using deep UV imaging from two independent space observatories: A… ▽ More The end of the Cosmic Dark Age marked the onset of reionization, driven by extreme-UV photons from the first galaxies. Direct detection of such photons has remained challenging due to strong intergalactic attenuation. Here, we report the first direct detection of ionizing photons at rest-frame wavelengths $350Å$, $392Å$, and $485Å$, using deep UV imaging from two independent space observatories: AstroSat and HST. These photons emerge from a stacked sample of spectroscopically confirmed Ly$α$ emitters at $5.9<z<6.0$ in the Hubble Ultra Deep Field identified with VLT/MUSE and JWST/NIRSpec. These detections imply a higher transparency of the interstellar and intergalactic media to ionizing radiation than predicted by current models. The stacked spectrum, representative of faint galaxies with $M_{\mathrm{UV}}=-18.77\pm0.05$ ($\sim0.1L^{\ast}$), exhibits a hard slope ($-2.3\pm0.1$) and produces ionizing photons with $\text{log}_{10}ξ_{\text{ion}}^{true}$ = $25.86 \pm 0.02$ Hz erg$^{-1}$ and escape fraction $f_{esc}\simeq 0.8$. Individual measurements reveal very blue UV continua ($β\leq -3$) for three galaxies), young ages ($< 6$ Myr for four), and low metallicities ($Z \sim 0.02 - 0.05\ Z_{\odot}$ for two), indicating the possible presence of very hot, massive stars capable of producing enough ionizing photons to drive cosmic reionization, thereby providing new constraints on its sources. Furthermore, detection of photons with energies $>24.6\ $eV provide evidence that HeI reionization has begun by this epoch. △ Less

Submitted 14 April, 2026; originally announced April 2026.

Comments: 26 pages, 15 figures, 3 tables, submitted to ApJ

The MUSE Ultra Deep Field (MUDF) VIII. The cool gas distribution surrounding galaxies at redshifts z ~ 0.5-2

Authors: Edoardo Santo, Michele Fumagalli, Seok-Jun Chang, Max Gronke, Rajeshwari Dutta, Matteo Fossati, Mitchell Revalski, Marc Rafelski

Abstract: We use deep MUSE data from the MUDF survey to investigate the cool gas around galaxies at redshifts 0.5 < z < 2. We constructed two samples: one sample for a down-the-barrel analysis, probing outflows via MgII absorption against galaxy continua, and the other sample for projected galaxy pairs to examine the gas around the foreground galaxies in the transverse direction. From down-the-barrel stacke… ▽ More We use deep MUSE data from the MUDF survey to investigate the cool gas around galaxies at redshifts 0.5 < z < 2. We constructed two samples: one sample for a down-the-barrel analysis, probing outflows via MgII absorption against galaxy continua, and the other sample for projected galaxy pairs to examine the gas around the foreground galaxies in the transverse direction. From down-the-barrel stacked spectra, we detected blueshifted MgII absorption, indicative of outflows, in which the absorption strength increases with stellar mass and star formation rate. Lower-mass galaxies exhibit weaker absorption, but higher outflow velocities, whereas higher-mass systems retain more cool gas with slower outflows. In the transverse direction, the absorption of MgII decreases with the impact parameter, following a shallow profile. Comparing observations with radiative transfer models, we found that extrapolating an expanding halo model constrained with down-the-barrel measurements to halo scales overestimates the observed equivalent widths, likely due to the outflow geometry and the absence of the interstellar medium in the model. Our results highlight that mass, outflow geometry, and gas retention shape the cool circumgalactic medium, and that the combination of absorption and emission diagnostics provides powerful constraints on the properties of the cold halo gas. △ Less

Submitted 23 March, 2026; originally announced March 2026.

Comments: 11 pages, 10 figures, 2 tables

Journal ref: A&A 707 A359 (2026)

MXDFz4.4: A LyC emitter 250Myr after the epoch of reionization and a first test of Ly-alpha morphology as a tracer of LyC escape at high redshift

Authors: Ilias Goovaerts, Marc Rafelski, Alexander Beckett, Grecco Oyarzùn, Annalisa Citro, Farhanul Hasan, Kalina V Nedkova, Calum Hawcroft, Anton M Koekemoer, Mitchell Revalski, Matthew J Hayes, Claudia Scarlata, Ray A Lucas, Norman A Grogin, David V Stark, Paolo Suin, Nor Pirzkal

Abstract: Assessing the contribution of ionizing sources to cosmic reionization is a central goal of extragalactic astrophysics. Understanding and quantifying ionizing escape remains challenging near the epoch of reionization. We present the highest-redshift Lyman continuum (LyC) emitter detected to date, MXDFz4.4 at z=4.442 in the MUSE eXtremely Deep Field, observed only ~0.25Gyr after the end of reionizat… ▽ More Assessing the contribution of ionizing sources to cosmic reionization is a central goal of extragalactic astrophysics. Understanding and quantifying ionizing escape remains challenging near the epoch of reionization. We present the highest-redshift Lyman continuum (LyC) emitter detected to date, MXDFz4.4 at z=4.442 in the MUSE eXtremely Deep Field, observed only ~0.25Gyr after the end of reionization. A high confidence Ly-alpha line confirms the redshift. LyC flux is detected at 5.3sigma in the F435W filter with a flux of 4.2+/-0.8nJy, corresponding to a flux measurement at 5.2sigma. After correcting for the intrinsic production of LyC photons and the IGM opacity at z=4.44, we derive high escape fractions, ranging from 50 - 100%. We apply established low-redshift tracers of LyC escape and, for the first time at high redshift, promising Ly-alpha morphological tracers such as the halo fraction. SED fitting indicates the presence of a recent burst of star formation; we explore its impact on the production and escape of ionizing photons. Ly-alpha-based tracers of LyC escape reveal a complex scenario in which the recent burst strong influences LyC production and escape, combined with a more evolved stellar population. This interpretation is supported by UV diagnostics, including the star formation rate surface density and sSFR. Our results provide cautious support for the Ly-alpha halo fraction as a LyC escape tracer at high redshift. Considering the burst-driven enhancement in LyC production and escape, we conclude that stochastic star formation in the early Universe likely plays a significant role in the contribution of galaxies to cosmic reionization. △ Less

Submitted 2 June, 2026; v1 submitted 4 March, 2026; originally announced March 2026.

Comments: 25 pages, 16 figures, 2 tables, 2 appendices. Updated to accepted version (ApJ)

Reference File Updates Following the Application of New Geometric Distortion and Walk Corrections I: Overview

Authors: Nick Indriolo, William J. Fischer, Elaine Frazer, David French, Sten Hasselquist, Jaquline Hernandez, Christian I. Johnson, Darshan Kakkad, Lauren P. Miller, Marc Rafelski, Ravi Sankrit

Abstract: The calibration of Cosmic Origins Spectrograph (COS) data is performed by the data processing pipeline known as CalCOS. CalCOS utilizes several reference files that store information required for data processing (e.g., dispersion solutions), and these reference files can be updated for the purpose of improving calibrated data products. In 2024 a major effort to improve the far-ultraviolet (FUV) ge… ▽ More The calibration of Cosmic Origins Spectrograph (COS) data is performed by the data processing pipeline known as CalCOS. CalCOS utilizes several reference files that store information required for data processing (e.g., dispersion solutions), and these reference files can be updated for the purpose of improving calibrated data products. In 2024 a major effort to improve the far-ultraviolet (FUV) geometric distortion, delta-geometric, and walk corrections was completed. Those three corrections occur early in the CalCOS workflow and shift photon events into the corrected reference frame ((XCORR, YCORR) coordinate system) in which subsequent calibration steps-and their reference files-are defined. This change necessitated the re-derivation of all "downstream" reference files in use at the time. Here we summarize the effort to create new versions of 56 reference files applicable to lifetime positions 1 through 6 and intended for use with the new geometric distortion, delta geometric, and walk corrections. The primary outcome of this work is improved wavelength and flux calibrations for COS FUV spectra. △ Less

Submitted 10 February, 2026; originally announced February 2026.

Comments: 15 pages

Report number: Instrument Science Report COS 2026-01

BEACON: JWST NIRCam Pure-parallel Imaging Survey. IV. A Systematic Search for Galaxy Overdensities and Evidence for Gas Accretion Mode Transition

Authors: Ryo Albert Sutanto, Takahiro Morishita, Tadayuki Kodama, Abdurro'uf, Larry D. Bradley, Andrew J. Bunker, Nima Chartab, Nuo Chen, Matthew J. Hayes, George Helou, Novan Saputra Haryana, Nicha Leethochawalit, Zhaoran Liu, Charlotte A. Mason, Marc Rafelski, Michael J. Rutkowski, Massimo Stiavelli, Kosuke Takahashi, Harry I. Teplitz, Michele Trenti, Tommaso Treu, Benedetta Vulcani, Yechi Zhang

Abstract: We systematically search for galaxy overdensities using 20 independent fields with a minimum of six filters (F090W, F115W, F150W, F277W, F356W, and F444W) from BEACON, the JWST Cycle 2 NIRCam pure-parallel imaging survey. We apply an adaptive kernel-density estimation method that incorporates the full photometric redshift probability distribution function of each galaxy to map galaxy overdensities… ▽ More We systematically search for galaxy overdensities using 20 independent fields with a minimum of six filters (F090W, F115W, F150W, F277W, F356W, and F444W) from BEACON, the JWST Cycle 2 NIRCam pure-parallel imaging survey. We apply an adaptive kernel-density estimation method that incorporates the full photometric redshift probability distribution function of each galaxy to map galaxy overdensities, and identify 207 significant ($>4\,σ$) overdensities at $1.5<z<5$. We measure the quenched-galaxy fraction, the median specific star formation rate (sSFR), the total halo mass, and the local galaxy density of each system. By investigating the correlation among these observables, we find that galaxy quenching proceeds in two paths:($i$) Overdensities within more massive halos exhibit higher quenched fractions and lower averaged sSFRs. This trend weakens at $z\gtrsim2$, consistent with cold gas streams penetrating shock-heated massive halos and sustaining star formation activity at early times. ($ii$) We also find a dependence of the same parameters on local densities at $z<2$, where the quenched fraction increases and the sSFR decreases toward higher densities. The environmental trend in sSFR weakens at $z\sim2$--$3$ and shows tentative evidence for a reversal at $z>3$, potentially due to a larger cold gas supply in earlier times. Our study reveals a complex interplay between individual galaxies and large-scale environmental properties, marking the onset of environmental effects on galaxy quenching in massive halos at cosmic noon. △ Less

Submitted 1 July, 2026; v1 submitted 4 February, 2026; originally announced February 2026.

Comments: 30 pages, 13 figures, 2 tables. Accepted for publication in ApJ

Direct Abundance Maps and Radial Metallicity Gradients of two Galaxies at z~4-5 in the GARDEN Survey

Authors: L. Stanghellini, S. A. Kassin, C. Pacifici, J. E. Morrison, M. E. Dickinson, E. Sukay, C. R. Mulcahey, L. E. Bergeron, M. W. Regan, C. N. A. Willmer, B. J. Weiner, N. Dencheva, D. Law, A. de la Vega, A. M. Koekemoer, C. Conselice, J. P. Gardner, Y. Guo, F. Hammer, A. Henry, B. W. Holwerda, J. Kartaltepe, R. A. Lucas, M. Puech, M. Rafelski , et al. (4 additional authors not shown)

Abstract: We investigate galaxies in the GARDEN (Galaxies at All Redshifts Deciphered and Explained with the NIRSpec MSA) survey that exhibit auroral emission lines, enabling spatially resolved measurements of electron temperature and direct oxygen abundances. Two galaxies in this survey have spectra suitable for this analysis: CANDELS 8005 at z=3.794 and CANDELS 7986 at z=4.702. For both galaxies, we measu… ▽ More We investigate galaxies in the GARDEN (Galaxies at All Redshifts Deciphered and Explained with the NIRSpec MSA) survey that exhibit auroral emission lines, enabling spatially resolved measurements of electron temperature and direct oxygen abundances. Two galaxies in this survey have spectra suitable for this analysis: CANDELS 8005 at z=3.794 and CANDELS 7986 at z=4.702. For both galaxies, we measure auroral and key nebular emission-line fluxes across their full extent, allowing direct-method oxygen abundance determinations in individual spatial pixels (spaxels). These observations demonstrate the viability of deep JWST/NIRSpec MSA spectroscopy for spatially resolved chemical analyses at high redshift, aided by weak nebular continua and low interstellar extinction. We derive global direct abundances of 12 + log(O/H) = 8.008$^{+0.025}_{-0.027}$ for CANDELS~8005 and 7.89$^{+0.027}_{-0.028}$ for CANDELS~7986. Emission-line diagnostics indicate neither galaxy hosts an active galactic nucleus. A first-order kinematic analysis suggests a potential merger in CANDELS~8005. The direct abundances are consistent with strong-line estimates based on our data and recent high-redshift calibrations. We build emission line, radial velocity, strong-line abundance indices, electron temperature, and direct abundance maps for both galaxies, thanks to the excellent spatial resolution. From the direct abundance maps we measure linear radial metallicity gradients of $-$0.111$^{+0.026}_{-0.025}$ dex kpc$^{-1}$ for CANDELS~8005 (statistically significant), and $-$0.0928$\pm$0.0880 dex kpc$^{-1}$ for CANDELS~7986, where the large uncertainties limit the significance of the result. These results provide a rare direct measurement of a radial metallicity gradient at $z>0$ from direct-method abundances, offering key observational support for inside-out galaxy growth with feedback-regulated chemical enrichment. △ Less

Submitted 31 March, 2026; v1 submitted 23 January, 2026; originally announced January 2026.

Comments: The Astrophysical Journal, in press

BEACON: JWST NIRCam Pure-parallel Imaging Survey. II. Physical Properties of $z=7-14$ Galaxies

Authors: Yechi Zhang, Takahiro Morishita, Kimi C. Kreilgaard, Charlotte A. Mason, Abdurro'uf, Hakim Atek, Marusa Bradac, Larry D. Bradley, Andrew J. Bunker, Viola Gelli, Novan Saputra Haryana, Matthew J. Hayes, George Helou, Nicha Leethochawalit, Zhaoran Liu, Marc Rafelski, Guido Roberts-Borsani, Michael Rutkowski, Claudia Scarlata, Massimo Stiavelli, Ryo A. Sutanto, Harry Teplitz, Tommaso Treu, Michele Trenti, Benedetta Vulcani , et al. (1 additional authors not shown)

Abstract: We present photometric properties of 161 galaxy candidates at $z=7-14$ selected from the second data release (DR2) of BEACON, a JWST Cycle 2 pure-parallel NIRCam imaging program. Carefully selected from 36 independent pointings (corresponding to $\sim350$\,arcmin$^2$ sky coverage), and hence with reduced cosmic variance, our galaxy candidates provide an unbiased sample for investigating galaxy pro… ▽ More We present photometric properties of 161 galaxy candidates at $z=7-14$ selected from the second data release (DR2) of BEACON, a JWST Cycle 2 pure-parallel NIRCam imaging program. Carefully selected from 36 independent pointings (corresponding to $\sim350$\,arcmin$^2$ sky coverage), and hence with reduced cosmic variance, our galaxy candidates provide an unbiased sample for investigating galaxy properties over a wide range of environments. We measure the physical properties, including UV continuum slope ($β_{\rm UV}$), stellar mass ($M_*$), star formation rate (SFR), and sizes. Our highest redshift galaxy candidate at $z=13.71\pm0.15$ has a remarkably bright UV luminosity of $M_{\rm UV}=-21.19\pm0.08$, making it the brightest galaxy at $z>12$ if spectroscopically confirmed. With an extremely blue UV slope, compact morphology, and high star formation rate surface density ($Σ_{\rm SFR}$), this candidate may have extremely low metallicity, high ionizing photon escape fraction, or contributions from an AGN. Among our multiple independent sightlines, we identify three fields of galaxy number overdensity with $>3σ$ significance. The properties of galaxies in various environments do not exhibit significant differences, implying either that accelerated galaxy evolution in overdense regions is not yet widespread at $z>7$, or that the current constraints are limited by sample size. Our simulations indicate that increasing the sample by an order of magnitude would allow such environmental trends to be robustly confirmed or ruled out, underscoring the importance of future pure-parallel observations. △ Less

Submitted 6 January, 2026; originally announced January 2026.

Comments: 18 pages, 13 figures, submitted to ApJ

The NIRISS PASSAGE Spectroscopic Redshift Catalog in COSMOS

Authors: Mason S. Huberty, Kalina V. Nedkova, Zahra Sattari, Vihang Mehta, Claudia Scarlata, Marc Rafelski, Matthew J. Hayes, Peter J. Watson, Ayan Acharyya, Jacob Levine, Benedetta Vulcani, Alexandra Le Reste, Farhanul Hasan, James Colbert, Michele Trenti, Xin Wang, Axel Runnholm, Matthew A. Malkan, Andrew J. Bunker, Anahita Alavi, Hakim Atek, Andrew J. Battisti, Y. Sophia Dai, Keunho Kim, Alaina Henry , et al. (12 additional authors not shown)

Abstract: We present the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) spectroscopic redshift catalog in the COSMOS field. PASSAGE is a JWST Cycle 1 Near Infrared Imager and Slitless Spectrograph (NIRISS) wide-field slitless spectroscopy (WFSS) pure-parallel survey, obtaining near-infrared spectra of thousands of extragalactic sources. 15 out of 63 PASSAGE fields fall w… ▽ More We present the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) spectroscopic redshift catalog in the COSMOS field. PASSAGE is a JWST Cycle 1 Near Infrared Imager and Slitless Spectrograph (NIRISS) wide-field slitless spectroscopy (WFSS) pure-parallel survey, obtaining near-infrared spectra of thousands of extragalactic sources. 15 out of 63 PASSAGE fields fall within the Hubble Space Telescope (HST) COSMOS footprint, of which 11 overlap with COSMOS-Web, a JWST treasury survey providing additional space-based photometry. We present our custom line-finding algorithm and visual inspection effort used to identify emission lines and derive the spectroscopic redshifts for line-emitting sources in PASSAGE. The line-finding algorithm identifies between ~200 and 950 line-emitting candidates per field, of which typically 47% were identified as true emission lines post visual inspection. We identify 2183 emission line sources at 0.08<z<4.7, 1896 of which have available COSMOS photometric redshifts. We find excellent redshift agreement between the COSMOS photometric redshifts and the PASSAGE spectroscopic redshifts for strong (S/N>5), multi-line emitting sources. This agreement weakens for PASSAGE single-line emitters with ambiguous identities. These single-line emitters are likely mis-identified around 18% of the time based on comparisons to photometric redshifts. We derive stellar masses using PASSAGE photometry and spectroscopic redshifts, in broad agreement with existing COSMOS-Web stellar masses, but with some discrepancy driven by redshift disagreements. We publicly release this spectroscopic redshift catalog, which will enable community-led science in prime extragalactic fields and serve as a crucial dataset for validating Euclid and Roman spectroscopy. △ Less

Submitted 28 April, 2026; v1 submitted 5 January, 2026; originally announced January 2026.

Comments: Accepted to ApJS. 24 pages, 9 figures

The Impact of the MAST Data Archive

Authors: Richard A. Shaw, Jenny L. Novacescu, Sarah Weissman, Travis A. Berger, Clara E. Brasseur, Jeff Chamblee, Brian Cherinka, Zachary R. Claytor, Theresa Dower, Chinwe Edeani, Scott W. Fleming, Jonathan R. Hargis, Julie Imig, Tim Januario, Karen Levay, Tim Kimball, Jenn Kotler, Hannah M. Lewis, Steve Lubow, Adrian Lucy, Brian McLean, Sunita G. Malla, Jacob Matuskey, Sophie J. Miller, Susan E. Mullally , et al. (9 additional authors not shown)

Abstract: The Barbara A. Mikulski Archive for Space Telescopes (MAST) hosts science-ready data products from over twenty NASA missions, plus community-contributed data collections, and other select surveys. The data support forefront research in the ultraviolet, optical, and near-infrared wavelength bands. We have constructed bibliographies for each mission from publications in nearly 40 professional journa… ▽ More The Barbara A. Mikulski Archive for Space Telescopes (MAST) hosts science-ready data products from over twenty NASA missions, plus community-contributed data collections, and other select surveys. The data support forefront research in the ultraviolet, optical, and near-infrared wavelength bands. We have constructed bibliographies for each mission from publications in nearly 40 professional journals, and have identified more than 37,000 refereed articles where investigators made a science usage of data hosted in MAST. The publication rate over the last 50 years shows that most MAST missions have had very high productivity during their in-service lifetimes, and have remained so for years or decades afterward. Annual citations to these publications, a measure of impact on research, are robust for most missions, with citations that grow over more than a decade. Most of the citations come from about 10% of articles within each mission. We examined the bibliographies of the active missions HST and JWST in greater detail. For HST the rate of archival publications exceeded those authored by the original observing teams within a decade of launch, and is now more than 3 times higher. Early indications hint that JWST archival articles could dominate the publication rate even sooner. The production of articles resulting from any given observing program can extend for decades. Programs with small and very large allocations of observing time tend to be particularly productive per unit of observing time. For HST in general, a first publication appears within 1.5 yr for 50% of observing programs, and within 3.8 yr for 80% of programs. We discuss various external factors that affect publication metrics, their strengths and limitations for measuring scientific impact, and the challenges of making meaningful comparisons of publication metrics across missions. △ Less

Submitted 19 December, 2025; originally announced December 2025.

Comments: 26 pages, 14 figures, 5 tables. To be published in PASP

Searching Within Galaxies for the Earliest Signs of Quenching With Spatially Resolved Star Formation Histories in UVCANDELS Galaxies at z< 0.3

Authors: Charlotte Olsen, Eric Gawiser, Charlotte Welker, Harry Teplitz, Kartheik Iyer, Xin Wang, Marc Rafelski, Rogier A. Windhorst, Anton Koekemoer, Anahita Alavi, Ben Sunnquist, Norman Grogin, Yicheng Guo, Christopher J. Conselice, L. Y. Aaron Yung, Kalina Nedkova, Bahram Mobasher, Ray A. Lucas, Vihang Mehta, Y. Sophia Dai, Jonathan P. Gardner

Abstract: Understanding the complicated processes that regulate star formation and cause a galaxy to become quiescent is key to our comprehension of galaxy evolution. We used eight well resolved star-forming z$<$ 0.3 galaxies from the UVCANDELS survey, where a total of 10 HST bands including UV follow up in UVIS/F275W allow us to reconstruct the star formation histories (SFHs) of regions across each galaxy.… ▽ More Understanding the complicated processes that regulate star formation and cause a galaxy to become quiescent is key to our comprehension of galaxy evolution. We used eight well resolved star-forming z$<$ 0.3 galaxies from the UVCANDELS survey, where a total of 10 HST bands including UV follow up in UVIS/F275W allow us to reconstruct the star formation histories (SFHs) of regions across each galaxy. This approach provides a powerful tool to explore the spatio-temporal connection between star formation and galaxy evolution. The spatial and temporal profiles of stellar mass and star formation rate surface density were obtained from the SFHs of these regions. We measure scaling relations and projected radial profiles of regions within each galaxy at the time of observation and at 1 Gyr lookback time, noting possible trends in the evolution. By comparing the change in star formation over time we can infer the timing and location of star formation and see early signs of star formation shut off before quenching occurs. We compared the star formation rate density -- stellar mass density scaling relations for individual galaxies as they evolve from 1 Gyr lookback time. The correlation lines pivot around a log-stellar mass surface density of 7.25 [$M_\odot$ $kpc^{-2}$] may be evidence of a self-regulating process on these scales. Radial profiles of galaxy Log sSFR show an overall decrease over 1 Gyr, but five galaxies show a greater change in Log sSFR at the outskirts than the center indicating a possible early onset of quenching in these galaxies. △ Less

Submitted 24 March, 2026; v1 submitted 4 November, 2025; originally announced November 2025.

Comments: 32 pages, 28 figures. Accepted to ApJ

Impact of Cosmic Filaments on Galaxy Morphological Evolution and Predictions of Early Cosmic Web Structure for Roman

Authors: Farhanul Hasan, Haowen Zhang, Viraj Pandya, Marc Rafelski, Joseph N. Burchett, Douglas Hellinger, Kalina V. Nedkova, Ilias Goovaerts, Nir Mandelker, Daisuke Nagai, Grecco A. Oyarzún, Joel R. Primack, Joanna Woo

Abstract: We leverage the IllustrisTNG cosmological simulations to test how the large-scale cosmic web shapes galaxy morphology and to forecast the early cosmic web structure that the Nancy Grace Roman Space Telescope will reveal. In the hydrodynamic TNG50 and $N$-body TNG50-Dark runs, we reconstruct the cosmic web at redshifts $z=0$, 0.5, 1, 2, 3, and 4 with the Monte Carlo Physarum Machine density estimat… ▽ More We leverage the IllustrisTNG cosmological simulations to test how the large-scale cosmic web shapes galaxy morphology and to forecast the early cosmic web structure that the Nancy Grace Roman Space Telescope will reveal. In the hydrodynamic TNG50 and $N$-body TNG50-Dark runs, we reconstruct the cosmic web at redshifts $z=0$, 0.5, 1, 2, 3, and 4 with the Monte Carlo Physarum Machine density estimator and the DisPerSE structure identification framework. We confirm that dark matter halos start out predominantly prolate (elongated) and their shapes are aligned with their nearest filaments; prolate galaxies retain strong shape-alignment with their outer halos to later times. The fraction of prolate galaxies and halos increases toward lower stellar mass, higher redshift, and lower-density filaments. Oblate and spheroidal galaxies show weaker trends with filament density, but spheroidal halos preferentially reside in higher-density filaments. We also find that higher-density filaments favor extended rotationally-supported disks, whereas lower-density filaments more often host smaller dispersion-supported systems. Then, generating mock galaxy samples from TNG100 and TNG50, we predict the early cosmic web accessible to Roman. We find that the spectroscopic emission-line depth planned for the High-Latitude Wide-Area Survey (HLWAS) yields a highly incomplete galaxy sample that does not accurately trace the $z=1$ cosmic web. A survey $\geq2.5\times$ deeper over a few square degrees would enable a proper reconstruction and reveal qualitatively correct filament-galaxy morphology relationships. Nevertheless, the planned HLWAS Deep field should still identify most galaxy overdensities; targeted deeper spectroscopy of these regions would efficiently and adequately map the early filamentary structure. △ Less

Submitted 15 April, 2026; v1 submitted 27 September, 2025; originally announced September 2025.

Comments: Accepted to ApJ. Dedicated to our colleague and co-author Joel Primack, who passed away during the revision process

Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE): Survey Overview

Authors: Matthew A. Malkan, Vihang Mehta, Ayan Acharyya, Hollis Akins, Anahita Alavi, Hakim Atek, Ivano Baronchelli, Andrew J. Battisti, Kit Boyett, Marusa Bradac, Sean Tyler Bruton, Andrew Bunker, Adam J. Burgasser, Caitlin Casey, Nuo Chen, James Colbert, Y. Sophia Dai, Max Franco, Clea Hannahs, Santosh Harish, Farhanul Hasan, Matthew James Hayes, Alaina L. Henry, Mason Huberty, Jeyhan Kartaltepe , et al. (27 additional authors not shown)

Abstract: During the second half of Cycle 1 of the James Webb Space Telescope (JWST), we conducted the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) program. PASSAGE received the largest allocation of JWST observing time in Cycle 1, 591 hours of NIRISS observations to obtain direct near-IR imaging and slitless spectroscopy. About two thirds of these were ultimately exec… ▽ More During the second half of Cycle 1 of the James Webb Space Telescope (JWST), we conducted the Parallel Application of Slitless Spectroscopy to Analyze Galaxy Evolution (PASSAGE) program. PASSAGE received the largest allocation of JWST observing time in Cycle 1, 591 hours of NIRISS observations to obtain direct near-IR imaging and slitless spectroscopy. About two thirds of these were ultimately executed, to observe 63 high-latitude fields in Pure Parallel mode. These have provided more than ten thousand near-infrared grism spectrograms of faint galaxies. PASSAGE brings unique advantages in studying galaxy evolution: A) Unbiased spectroscopic search, without prior photometric pre-selection. By including the most numerous galaxies, with low masses and strong emission lines, slitless spectroscopy is the indispensable complement to any pre-targeted spectroscopy; B) The combination of several dozen independent fields to overcome cosmic variance; C) Near-infrared spectral coverage, often spanning the full range from 1.0--2.3 $μ$m, with minimal wavelength gaps, to measure multiple diagnostic rest-frame optical lines, minimizing sensitivity to dust reddening; D) JWST's unprecedented spatial resolution, in some cases using two orthogonal grism orientations, to overcome contamination due to blending of overlapping spectra; E) Discovery of rare bright objects especially for detailed JWST followup. PASSAGE data are public immediately, and our team plans to deliver fully-processed high-level data products. In this PASSAGE overview, we describe the survey and data quality, and present examples of these accomplishments in several areas of current interest in the evolution of emission-line galaxy properties, particularly at low masses. △ Less

Submitted 30 August, 2025; originally announced September 2025.

Comments: 22 pages, 18 figures

Spatially resolved gas-phase metallicity at z~2-3 with JWST/NIRISS

Authors: Ayan Acharyya, Peter J. Watson, Benedetta Vulcani, Tommaso Treu, Kalina V. Nedkova, Andrew J. Bunker, Vihang Mehta, Hakim Atek, Andrew J. Battisti, Farhanul Hasan, Matthew J. Hayes, Mason Huberty, Tucker Jones, Nicha Leethochawalit, Yu-Heng Lin, Matthew A. Malkan, Benjamin Metha, Themiya Nanayakkara, Marc Rafelski, Zahra Sattari, Claudia Scarlata, Xin Wang, Caitlin M. Casey, Andrea Grazian, Anton M. Koekemoer , et al. (2 additional authors not shown)

Abstract: Spatially resolved gas-phase metallicity maps are a crucial element in understanding the chemical evolution of galaxies. We present spatially resolved metallicity maps obtained from NIRISS/WFSS observations. This is the first such work presenting multiple individual galaxies. We investigate the source of ionisation, metallicity and its relation to star-formation in a spatially-resolved sense for a… ▽ More Spatially resolved gas-phase metallicity maps are a crucial element in understanding the chemical evolution of galaxies. We present spatially resolved metallicity maps obtained from NIRISS/WFSS observations. This is the first such work presenting multiple individual galaxies. We investigate the source of ionisation, metallicity and its relation to star-formation in a spatially-resolved sense for a sample of eight galaxies -- four from JWST-PASSAGE and four from GLASS-JWST ERS. All but one galaxy are in the redshift range $1.9 \leq z \leq 2$, the outlier being at $z = 3.1$. Our sample covers a range of $8.0 <$ \logM $< 9.5$ in stellar mass, $0.2 <$ $\log{\rm{(SFR}}$/\Msunpyr) $< 1.1$ in star-formation rate (SFR) and $7.8 <$ \logOH $< 9.0$ in global metallicity. As a solution to the challenge of SF-AGN demarcation in absence of resolved \halpha, we present a new SF-demarcation line in the \textit{OHNO} parameter space based on MAPPINGS v5.1 publicly available \hii region model grids. We present the mass-metallicity gradient relation for our sample, which showed no clear trend with stellar mass, perhaps hinting at the fact that the high-$z$ galaxies have not yet started their accretion dominated phase. By interpreting the correlation between spatially resolved metallicity and SFR maps as a proxy for effective timescales of metal-transport in galaxies, we find a weak trend such that this timescale increases with stellar mass, implying a more effective feedback in lower mass galaxies. △ Less

Submitted 8 June, 2026; v1 submitted 7 August, 2025; originally announced August 2025.

Comments: 14 pages, 10 figures, 2 tables. Submitted to A&A

Unraveling the Lyman Continuum Emission of Ion3: Insights from HST multi-band imaging and X-Shooter spectroscopy

Authors: U. Meštrić, E. Vanzella, A. Beckett, M. Rafelski, C. Grillo, M. Giavalisco, M. Messa, M. Castellano, F. Calura, G. Cupani, A. Zanella, P. Bergamini, M. Meneghetti, A. Mercurio, P. Rosati, M. Nonino, K. Caputi, A. Comastri

Abstract: We provide a comprehensive analysis of Ion3, the most distant LyC leaker at $z=3.999$, using multi-band HST photometry and X-Shooter spectroscopy. Deep HST F390W imaging probe uncontaminated LyC flux blueward $\sim$880Å, while the non-ionizing UV 1500Å/2800Å~flux is probed with the F814W/F140W band. High angular resolution allows us to properly mask low-$z$ interlopers and prevent contamination of… ▽ More We provide a comprehensive analysis of Ion3, the most distant LyC leaker at $z=3.999$, using multi-band HST photometry and X-Shooter spectroscopy. Deep HST F390W imaging probe uncontaminated LyC flux blueward $\sim$880Å, while the non-ionizing UV 1500Å/2800Å~flux is probed with the F814W/F140W band. High angular resolution allows us to properly mask low-$z$ interlopers and prevent contamination of measured LyC radiation. We confirm the detection of LyC flux at SNR $\sim$3.5 and estimate the escape fraction of ionizing photons to be in the range $f_{\rm esc, rel}$ = 0.06 -- 1, depending on the adopted IGM attenuation. Morphological analysis reveals a clumpy structure made of two main components, with effective radii of R$_{\rm eff}$ $\sim$180 pc and R$_{\rm eff}$ < 100 pc, and a total estimated de-lensed area in the rest-frame 1600Å~of 4.2~kpc$^{2}$. We confirm the presence of faint ultraviolet spectral features HeII$λ$1640, CIII]$λ$1907,1909 and [NeIII]$λ$3968, with rest-frame EW(HeII) = (1.6$\pm$0.7)Å and EW(CIII]) = (6.5$\pm$3)Å. From [OII]$λ$$λ$3726,3729 and [CIII]$λ$1909/CIII]$λ$1906 we derive electron densities $n_{\rm e}^{\rm [OII]}$ = 2300$\pm$1900 cm$^{-3}$ and $n_{\rm e}^{\rm CIII]}$ > 10$^{4}$ cm$^{-3}$, corresponding to an ISM pressure log(P/k) > 7.90. Furthermore, we derive an intrinsic SFR(H$α$) $\approx$ 77 M$_{\odot}$ yr$^{-1}$ (corresponding to $Σ_{\rm SFR} = 20$~M$_{\odot}$~yr$^{-1}$~kpc$^{-2}$ for the entire galaxy) and sub-solar metallicity $12+\rm log(O/H)$ = 8.02$\pm$0.20 using the EW(CIII]) as a diagnostic. The detection of [NeIII]$λ$3968 line and [OII]$λ$$λ$3726,3729, provide an estimate of the ratio [OIII]$λ$5007/[OII]$λ$$λ$3727,29 of O32 > 50 and high ionization parameter log$U$ > $-$1.5 using empirical and theoretical correlations. △ Less

Submitted 25 April, 2025; originally announced April 2025.

Comments: 12 pages, 12 figures, Accepted to A&A

Journal ref: A&A 698, A203 (2025)

Recent star formation in 0.5<z<1.5 quiescent galaxies

Authors: Michael J. Rutkowski, Bonnabelle Zabelle, Tyler Hagen, Seth Cohen, Christopher Conselice, Norman Grogin, Yicheng Guo, Matthew Hayes, Sugata Kaviraj, Anton Koekemoer, Ray A. Lucas, Kameswara Bharadwaj Mantha, Alec Martin, Vihang Mehta, Bahram Mobasher, Nimish Hathi, Kalina V. Nedkova, Robert O'Connell, Marc Rafelski, Claudia Scarlata, Harry I. Teplitz, Xin Wang, Rogier Windhorst, Aaron Yung, the UVCANDELS Team

Abstract: Observations of massive, quiescent galaxies reveal a relatively uniform evolution: following prolific star formation in the early universe, these galaxies quench and transition to their characteristic quiescent state in the local universe. The debate on the relative role and frequency of the process(es) driving this evolution is robust. In this letter, we identify 0.5<z<1.5 massive, quiescent gala… ▽ More Observations of massive, quiescent galaxies reveal a relatively uniform evolution: following prolific star formation in the early universe, these galaxies quench and transition to their characteristic quiescent state in the local universe. The debate on the relative role and frequency of the process(es) driving this evolution is robust. In this letter, we identify 0.5<z<1.5 massive, quiescent galaxies in the HST/UVCANDELS extragalactic deep fields using traditional color selection methods and model their spectral energy distributions, which incorporates novel UV images. This analysis reveals ~15% of massive, quiescent galaxies have experienced minor, recent star formation(<10% of total stellar mass within the past ~1Gyr). We find only a marginal, positive correlation between the probability for recent star formation and a measure of the richness of the local environment from a statistical analysis. Assuming the recent star formation present in these quiescent galaxies is physically linked to the local environment, these results suggest only a minor role for dynamic external processes (galaxy mergers and interactions) in the formation and evolution of these galaxies at this redshift. △ Less

Submitted 9 April, 2025; v1 submitted 7 April, 2025; originally announced April 2025.

Comments: Accepted to ApJ Letters; updated author affilations

A [CII]-158-micron Survey of DLA galaxies at z~4: Observations of Dense and Metal-Enriched Neutral Gas within the Circumgalactic Medium of Star-Forming Galaxies

Authors: Marcel Neeleman, Nissim Kanekar, J. Xavier Prochaska, Marc A. Rafelski, Lordrick A. Kahinga

Abstract: We present a survey undertaken with the Atacama Large Millimeter/submillimeter Array (ALMA) to study the galaxies associated with a representative sample of 16 damped Ly-alpha absorbers (DLAs) at z~4.1-4.5, using the [CII]-158-micron ([CII]) line. We detect seven [CII]-emitting galaxies in the fields of 5 DLAs, all of which have absorption metallicity [M/H] > -1.5. We find that the detectability o… ▽ More We present a survey undertaken with the Atacama Large Millimeter/submillimeter Array (ALMA) to study the galaxies associated with a representative sample of 16 damped Ly-alpha absorbers (DLAs) at z~4.1-4.5, using the [CII]-158-micron ([CII]) line. We detect seven [CII]-emitting galaxies in the fields of 5 DLAs, all of which have absorption metallicity [M/H] > -1.5. We find that the detectability of these HI-selected galaxies with ALMA is a strong function of DLA metallicity, with a detection rate of 71^{+11}_{-20}% for DLAs with [M/H] > -1.5 and 0^{+18}% for DLAs with [M/H] <-1.5. The identified DLA galaxies have far-infrared properties similar to those of typical star-forming galaxies at z ~ 4, with estimated obscured star-formation rates ranging from ~6 Msun/yr to 110 Msun/yr. High-metallicity DLAs therefore provide an efficient way to identify and study samples of high-redshift, star-forming galaxies without preselecting the galaxies by their emission properties. The agreement between the velocities of the metal absorption lines of the DLA and the [CII] emission line of the DLA galaxy indicates that the metals within the DLA originated in the galaxy. With observed impact parameters between 14 and 59 kpc, this indicates that star-forming galaxies at z ~ 4 have a substantial reservoir of dense, cold neutral gas within their circumgalactic medium that has been enriched with metals from the galaxy. △ Less

Submitted 4 April, 2025; originally announced April 2025.

Comments: Published in the Astrophysical Journal

Journal ref: 2025, ApJ, 983, 26

The Parallel Ionizing Emissivity Survey (PIE). I. Survey design and selection of candidate Lyman Continuum leakers at 3.1<z<3.5

Authors: Alexander Beckett, Marc Rafelski, Claudia Scarlata, Wanjia Hu, Keunho Kim, Ilias Goovaerts, Matthew A. Malkan, Wayne Webb, Harry Teplitz, Matthew Hayes, Vihang Mehta, Anahita Alavi, Andrew J. Bunker, Annalisa Citro, Nimish Hathi, Alaina Henry, Alexandra Le Reste, Alessia Moretti, Michael J. Rutkowski, Maxime Trebitsch, Anita Zanella

Abstract: We present the survey design and initial results from the Parallel Ionizing Emissivity (PIE) survey. PIE is a large HST survey designed to detect Lyman continuum (LyC) emitting galaxies at 3.1$<$ z $<$3.5 and stack their images in order to measure average LyC escape fractions as a function of galaxy properties. PIE has imaged 37 independent fields in three filters (F336W, F625W and F814W), of whic… ▽ More We present the survey design and initial results from the Parallel Ionizing Emissivity (PIE) survey. PIE is a large HST survey designed to detect Lyman continuum (LyC) emitting galaxies at 3.1$<$ z $<$3.5 and stack their images in order to measure average LyC escape fractions as a function of galaxy properties. PIE has imaged 37 independent fields in three filters (F336W, F625W and F814W), of which 18 are observed with a fourth band (F475W) from the accompanying PIE+ program. We use photometric colors to select candidate Lyman Break Galaxies (LBGs) at 3.1$<$ z $<$3.5, which can be followed up using ground-based spectrographs to confirm their redshifts. Unlike previous surveys, we use many independent fields to remove biases caused by correlated absorption in the IGM. In this paper, we describe the survey design, photometric measurements, and the use of mock galaxy samples to optimize our color selection. With 3 filters, we can select a galaxy sample of which $\approx$90\% are LBGs and over 30\% lie in the 3.1$<$ z $<$3.5 range for which we can detect uncontaminated LyC emission in F336W. We also use mock IGM sightlines to measure the expected transmission of the IGM, which will allow us to determine escape fractions from our stacked galaxies. We color-select $\approx$1400 galaxies, and predict that this includes $\approx$80 LyC-emitting galaxies and $\approx$500 that we can use in stacking. Finally, we present the Keck/LRIS spectrum of a galaxy at z $\approx$ 2.99, demonstrating that we can confirm the redshifts of z $\sim$ 3 galaxies from the ground. △ Less

Submitted 13 October, 2025; v1 submitted 26 March, 2025; originally announced March 2025.

Comments: 21 pages, 7 tables, 15 figures, published in the Astrophysical Journal

Journal ref: 2025 ApJ 992 155

Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. V. The Expanded Sample

Authors: Mitchell Revalski, D. Michael Crenshaw, Garrett E. Polack, Marc Rafelski, Steven B. Kraemer, Travis C. Fischer, Beena Meena, Henrique R. Schmitt, Anna Trindade Falcão, Julia Falcone, Maura Kathleen Shea

Abstract: We present spatially-resolved measurements of the ionized gas masses and mass outflow rates for six low-redshift ($z \leq$ 0.02) active galaxies. In this study, we expand our sample to galaxies with more complex gas kinematics modeled as outflows along a galactic disk that is ionized by the active galactic nucleus (AGN) bicone. We use Hubble Space Telescope (HST) Space Telescope Imaging Spectrogra… ▽ More We present spatially-resolved measurements of the ionized gas masses and mass outflow rates for six low-redshift ($z \leq$ 0.02) active galaxies. In this study, we expand our sample to galaxies with more complex gas kinematics modeled as outflows along a galactic disk that is ionized by the active galactic nucleus (AGN) bicone. We use Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) spectroscopy, Wide Field Camera 3 (WFC3) narrow-band imaging, and the photoionization modeling technique that we developed in Revalski et al. (2022) to calculate ionized gas masses using the [O III]/H$β$ ratios at each radius. We combine these with existing kinematic models to derive mass and energy outflow rates, which exhibit substantial radial variations due to changes in the outflow velocities. The full sample of 12 galaxies from this series of studies spans 10$^3$ in bolometric luminosity, and we find that the outflows contain ionized gas masses of $M \approx 10^{4.6} - 10^{7.2}$ $M_{\odot}$, reach maximum mass outflow rates of $\dot M_{out} \approx 0.1 - 13$ $M_{\odot}$ yr$^{-1}$, and encompass kinetic energies of $E \approx 10^{52} - 10^{56}$ erg. These energetic properties positively correlate with AGN luminosity. The outflow energetics are less than benchmarks for effective feedback from theoretical models, but the evacuation of gas and injection of energy may still generate long term effects on star-formation in these nearby galaxies. These results highlight the necessity of high spatial resolution imaging and spectroscopy for accurately modeling ionized outflows in active galaxies. △ Less

Submitted 21 March, 2025; originally announced March 2025.

Comments: Accepted for Publication in ApJ on March 14, 2025. The paper has 14 pages and 5 figures

A massive HI-absorption-selected galaxy at $z\approx2.356$

Authors: Balpreet Kaur, Nissim Kanekar, Marcel Neeleman, Yongda Zhu, J. Xavier Prochaska, Marc Rafelski, George D. Becker

Abstract: We use the Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) to detect $\rm CO(1-0)$, $\rm CO(3-2)$, and rest-frame 349-GHz continuum emission from an HI-selected galaxy, DLA1020+2733g, at $z\approx2.3568$ in the field of the $z=2.3553$ damped Lyman-$α$ absorber (DLA) towards QSO J1020+2733. The VLA $\rm CO(1-0)$ detection yields a molecular gas mass… ▽ More We use the Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) to detect $\rm CO(1-0)$, $\rm CO(3-2)$, and rest-frame 349-GHz continuum emission from an HI-selected galaxy, DLA1020+2733g, at $z\approx2.3568$ in the field of the $z=2.3553$ damped Lyman-$α$ absorber (DLA) towards QSO J1020+2733. The VLA $\rm CO(1-0)$ detection yields a molecular gas mass of $(2.84\pm0.42)\times10^{11}\times(α_{\rm CO}/4.36)\,\rm{M_\odot}$, the largest ever measured in an HI-selected galaxy. The DLA metallicity is $+0.28 \pm 0.16$, from the ZnII$\, \lambda2026$Å absorption line detected in a Keck Echellette Spectrograph and Imager spectrum. This continues the trend of high-metallicity DLAs being frequently associated with massive galaxies. We obtain a star-formation rate (SFR) of $\lesssim400~$M$_\odot~$yr$^{-1}$ from the rest-frame 349-GHz continuum emission, and a relatively long molecular gas depletion timescale of $\gtrsim0.6~$Gyr. The excitation of the J=3 rotational level is sub-thermal, with $r_{31}\equiv{L'_{\rm{CO(3-2)}}/L'_{\rm{CO(1-0)}}}=0.513\pm0.081$, suggesting that DLA1020+2733g has a low SFR surface density. The large velocity spread of the CO lines, $\approx500~\rm km~s^{-1}$, and the long molecular gas depletion timescale suggest that DLA1020+2733g is likely to be a cold rotating-disk galaxy. △ Less

Submitted 26 February, 2025; originally announced February 2025.

Comments: Accepted for publication in ApJ Letters; 11 pages, 6 figures, and 2 Tables

The JWST/PASSAGE Survey: Testing Reionization Histories with JWST's First Unbiased Survey for Lyman alpha Emitters at Redshifts 7.5-9.5

Authors: Axel Runnholm, Matthew J. Hayes, Vihang Mehta, Matthew A. Malkan, Claudia Scarlata, Kalina V. Nedkova, Marc Rafelski, Benedetta Vulcani, Mason Huberty, E. Christian Herenz, Anne Hutter, Sean Bruton, Ayan Acharyya, Hakim Atek, Ivano Baronchelli, Andrew J. Battisti, Maruša Bradač, Andrew J. Bunker, Y. Sophia Dai, Clea Hannahs, Farhanul Hasan, Keunho J. Kim, Nicha Leethochawalit, Yu-Heng Lin, Michael J. Rutkowski , et al. (3 additional authors not shown)

Abstract: Lyman $α$ (Ly$α$) emission is one of few observable features of galaxies that can trace the neutral hydrogen content in the Universe during the Epoch of Reionization (EoR). To accomplish this we need an efficient way to survey for Ly$α$ emitters (LAEs) at redshifts beyond 7, requiring unbiased emission-line observations that are both sufficiently deep and wide to cover enough volume to detect them… ▽ More Lyman $α$ (Ly$α$) emission is one of few observable features of galaxies that can trace the neutral hydrogen content in the Universe during the Epoch of Reionization (EoR). To accomplish this we need an efficient way to survey for Ly$α$ emitters (LAEs) at redshifts beyond 7, requiring unbiased emission-line observations that are both sufficiently deep and wide to cover enough volume to detect them. Here we present results from PASSAGE -- a pure-parallel JWST/NIRISS slitless spectroscopic survey to detect Ly$α$ emitters deep into the EoR, without the bias of photometric preselection. We identify four LAEs at $7.5\leq z\leq9.5$ in four surveyed pointings, and estimate the luminosity function (LF). We find that the LF does show a marked decrease compared to post-reionization measurements, but the change is a factor of $\lesssim 10$, which is less than expected from theoretical calculations and simulations, as well as observational expectations from the pre-JWST literature. Modeling of the IGM and expected \lya\ profiles implies these galaxies reside in ionized bubbles of $\gtrapprox 2$ physical Mpc. We also report that in the four fields we detect {3,1,0,0} LAEs, which could indicate strong field-to-field variation in the LAE distribution, consistent with a patchy HI distribution at $z\sim8$. We compare the recovered LAE number counts with expectations from simulations and discuss the potential implications for reionization and its morphology. △ Less

Submitted 26 February, 2025; originally announced February 2025.

Comments: Resubmitted to the ApJ after addressing referee comments

The Qz5 Survey (I): How the HI Mass Density of the Universe Evolves With Cosmic Time

Authors: Grecco A. Oyarzún, Marc Rafelski, Lise Christensen, Fiona Ozyurt, Regina A. Jorgenson, Marcel Neeleman, Michele Fumagalli, J. Xavier Prochaska, G. Worseck, M. E. Wisz, George D. Becker, Sebastián López

Abstract: We report that the neutral hydrogen (HI) mass density of the Universe ($ρ_{HI}$) increases with cosmic time since $z \sim 5$, peaks at $z \sim 3$, and then decreases toward $z \sim 0$. This is the first result of Qz5, our spectroscopic survey of 63 quasars at $z \gtrsim 5$ with VLT/X-SHOOTER and Keck/ESI aimed at characterizing intervening HI gas absorbers at $z \sim 5$. The main feature of Qz5 is… ▽ More We report that the neutral hydrogen (HI) mass density of the Universe ($ρ_{HI}$) increases with cosmic time since $z \sim 5$, peaks at $z \sim 3$, and then decreases toward $z \sim 0$. This is the first result of Qz5, our spectroscopic survey of 63 quasars at $z \gtrsim 5$ with VLT/X-SHOOTER and Keck/ESI aimed at characterizing intervening HI gas absorbers at $z \sim 5$. The main feature of Qz5 is the high resolution ($R \sim 7000 - 9000$) of the spectra, which allows us to (1) accurately detect high column density HI gas absorbers in an increasingly neutral intergalactic medium at $z \sim 5$ and (2) determine the reliability of previous $ρ_{HI}$ measurements derived with lower resolution spectroscopy. We find 5 intervening Damped Ly$α$ absorbers (DLAs) at $z > 4.5$, which corresponds to the lowest DLA incidence rate ($0.034^{0.05}_{0.02}$) at $z \gtrsim 2$. We also measure the lowest $ρ_{HI}$ at $z \gtrsim 2$ from our sample of DLAs and subDLAs, corresponding to $ρ_{HI} = 0.56^{0.82}_{0.31} \times 10^8~$M$_{\odot}~$Mpc$^{-3}$ at $z \sim 5$. Taking into account our measurements at $z \sim 5$ and systematic biases in the DLA detection rate at lower spectral resolutions, we conclude that $ρ_{HI}$ doubles from $z \sim 5$ to $z \sim 3$. From these results emerges a qualitative agreement between how the cosmic densities of HI gas mass, molecular gas mass, and star-formation rate build up with cosmic time. △ Less

Submitted 21 March, 2025; v1 submitted 7 February, 2025; originally announced February 2025.

Comments: Accepted for publication in ApJ. Main text is composed of 18 pages and 8 figures

Systematic Bias in Ionizing Radiation Escape Fraction Measurements from Foreground Large-Scale Structures

Authors: C. Scarlata, W. Hu, M. J. Hayes, S. Taamoli, A. A. Khostovan, C. M. Casey, A. L. Faisst, J. S. Kartaltepe, Y. Lin, M. Salvato, M. Rafelski

Abstract: We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape fractions. Using a sample of 268 spectroscopically confirmed background galaxies at 2.7<z<3.0 and a galaxy density map at z~2.5 within the COSMOS field, we measure… ▽ More We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape fractions. Using a sample of 268 spectroscopically confirmed background galaxies at 2.7<z<3.0 and a galaxy density map at z~2.5 within the COSMOS field, we measure the Lya transmission photometrically, leveraging the multiwavelength data available from the COSMOS2020 catalog. Our results reveal a weak but statistically significant positive correlation between Lya optical depth and galaxy density contrast, suggesting that overdense regions are enriched in neutral gas, which could bias escape fraction measurements. This emphasizes the need to account for the large-scale structure of the IGM in analyses of ionizing radiation escape fractions, and highlights the advantages of a photometric approach for increasing the number of sampled lines of sight across large fields. The photometric redshifts provided by upcoming all-sky surveys, such as Euclid, will make it possible to account for this effect across widely separated fields. △ Less

Submitted 22 April, 2025; v1 submitted 31 January, 2025; originally announced January 2025.

Comments: Replaced with version accepted for publication on ApJ

ODIN: Star Formation Histories Reveal Formative Starbursts Experienced by Lyman Alpha Emitting Galaxies at Cosmic Noon

Authors: Nicole M. Firestone, Eric Gawiser, Kartheik G. Iyer, Kyoung-Soo Lee, Vandana Ramakrishnan, Francisco Valdes, Changbom Park, Yujin Yang, Anahita Alavi, Robin Ciardullo, Norman Grogin, Caryl Gronwall, Lucia Guaita, Sungryong Hong, Ho Seong Hwang, Sang Hyeok Im, Woong-Seob Jeong, Seongjae Kim, Anton M. Koekemoer, Ankit Kumar, Jaehyun Lee, Vihang Mehta, Gautam Nagaraj, Julie Nantais, Laura Prichard , et al. (5 additional authors not shown)

Abstract: In this work, we test the frequent assumption that Lyman Alpha Emitting galaxies (LAEs) are experiencing their first major burst of star formation at the time of observation. To this end, we identify 74 LAEs from the ODIN Survey with rest-UV-through-NIR photometry from UVCANDELS. For each LAE, we perform non-parametric star formation history (SFH) reconstruction using the Dense Basis Gaussian proc… ▽ More In this work, we test the frequent assumption that Lyman Alpha Emitting galaxies (LAEs) are experiencing their first major burst of star formation at the time of observation. To this end, we identify 74 LAEs from the ODIN Survey with rest-UV-through-NIR photometry from UVCANDELS. For each LAE, we perform non-parametric star formation history (SFH) reconstruction using the Dense Basis Gaussian process-based method of spectral energy distribution fitting. We find that a strong majority (67%) of our LAE SFHs align with the frequently assumed archetype of a first major star formation burst, with at most modest star formation rates (SFRs) in the past. However, the rest of our LAE SFHs have significant amounts of star formation in the past, with 28% exhibiting earlier bursts of star formation with the ongoing burst having the highest SFR (dominant bursts), and the final 5% having experienced their highest SFR in the past (non-dominant bursts). Combining the SFHs indicating first and dominant bursts, ~95% of LAEs are experiencing their largest burst yet -- a formative burst. We also find that the fraction of total stellar mass created in the last 200 Myr is ~1.3 times higher in LAEs than in mass-matched Lyman Break Galaxy (LBG) samples, and that a majority of LBGs are experiencing dominant bursts, reaffirming that LAEs differ from other star forming galaxies. Overall, our results suggest that multiple evolutionary paths can produce galaxies with strong observed Ly$α$ emission. △ Less

Submitted 2 June, 2025; v1 submitted 14 January, 2025; originally announced January 2025.

Comments: 15 pages, 6 figures; accepted to ApJL

The Cosmic Evolution Early Release Science Survey (CEERS)

Authors: Steven L. Finkelstein, Micaela B. Bagley, Pablo Arrabal Haro, Mark Dickinson, Henry C. Ferguson, Jeyhan S. Kartaltepe, Dale D. Kocevski, Anton M. Koekemoer, Jennifer M. Lotz, Casey Papovich, Pablo G. Perez-Gonzalez, Nor Pirzkal, Rachel S. Somerville, Jonathan R. Trump, Guang Yang, L. Y. Aaron Yung, Adriano Fontana, Andrea Grazian, Norman A. Grogin, Lisa J. Kewley, Allison Kirkpatrick, Rebecca L. Larson, Laura Pentericci, Swara Ravindranath, Stephen M. Wilkins , et al. (74 additional authors not shown)

Abstract: We present the Cosmic Evolution Early Release Science (CEERS) Survey, a 77.2 hour Director's Discretionary Early Release Science Program. CEERS demonstrates, tests, and validates efficient extragalactic surveys using coordinated, overlapping parallel observations with the JWST instrument suite, including NIRCam and MIRI imaging, NIRSpec low (R~100) and medium (R~1000) resolution spectroscopy, and… ▽ More We present the Cosmic Evolution Early Release Science (CEERS) Survey, a 77.2 hour Director's Discretionary Early Release Science Program. CEERS demonstrates, tests, and validates efficient extragalactic surveys using coordinated, overlapping parallel observations with the JWST instrument suite, including NIRCam and MIRI imaging, NIRSpec low (R~100) and medium (R~1000) resolution spectroscopy, and NIRCam slitless grism (R~1500) spectroscopy. CEERS targets the Hubble Space Telescope-observed region of the Extended Groth Strip (EGS) field, supported by a rich set of multiwavelength data. CEERS facilitated immediate community science in both of the extragalactic core JWST science drivers ``First Light" and ``Galaxy Assembly," including: 1) The discovery and characterization of large samples of galaxies at z >~ 10 from ~90 arcmin^2 of NIRCam imaging, constraining their abundance and physical nature; 2) Deep spectra of >1000 galaxies, including dozens of galaxies at 6<z<10, enabling redshift measurements and constraints on the physical conditions of star-formation and black hole growth via line diagnostics; 3) Quantifying the first bulge, bar and disk structures at z>3; and 4) Characterizing galaxy mid-IR emission with MIRI to study dust-obscured star-formation and supermassive black hole growth at z~1-3. As a legacy product for the community, the CEERS team has provided several data releases, accompanied by detailed notes on the data reduction procedures and notebooks to aid in reproducibility. In addition to an overview of the survey and quality of the data, we provide science highlights from the first two years with CEERS data. △ Less

Submitted 7 January, 2025; originally announced January 2025.

Comments: 38 pages, 13 figures, 6 tables

The MUSE Ultra Deep Field: A 5 Mpc stretch of the z $\approx$ 4 cosmic web revealed in emission

Authors: Davide Tornotti, Michele Fumagalli, Matteo Fossati, Fabrizio Arrigoni Battaia, Alejandro Benitez-Llambay, Pratika Dayal, Rajeshwari Dutta, Celine Peroux, Marc Rafelski, Mitchell Revalski

Abstract: We detect Ly$α$ emission from a ~5 Mpc-long (comoving) portion of the cosmic web hosting an overdensity ($δ\approx 25$) of 19 Ly$α$ emitters (LAEs) at $z\approx 4$ within the MUSE Ultra Deep Field (MUDF), reaching an average surface brightness (SB) of $5\times 10^{-20}~\rm{erg~s^{-1}~ cm^{-2}~arcsec^{-2}}$. This large-scale structure has an average SB similar to the filament across the two MUDF qu… ▽ More We detect Ly$α$ emission from a ~5 Mpc-long (comoving) portion of the cosmic web hosting an overdensity ($δ\approx 25$) of 19 Ly$α$ emitters (LAEs) at $z\approx 4$ within the MUSE Ultra Deep Field (MUDF), reaching an average surface brightness (SB) of $5\times 10^{-20}~\rm{erg~s^{-1}~ cm^{-2}~arcsec^{-2}}$. This large-scale structure has an average SB similar to the filament across the two MUDF quasars at $z\approx 3.22$. However, deep multiwavelength data do not show a clear presence of active galactic nuclei, suggesting that the emission is mainly regulated by the underlying gas density. We find $\approx 0.2$ dex higher star formation compared to control samples and a remarkable predominance (5/7) of blue-peaked emission lines in the spectra of the embedded LAEs, indicative of favorable conditions for gas accretion. Lastly, we quantify the contribution of intragalactic gas to the Ly$α$ SB profile at large distances from LAEs. By studying samples of filaments detected in emission within diverse environments, we are finally gaining new insight into the physics of gas accretion within the cosmic web. △ Less

Submitted 14 February, 2025; v1 submitted 9 December, 2024; originally announced December 2024.

Comments: 11 pages, 6 figures; accepted for publication in ApJ Letters

BEACON: JWST NIRCam Pure-parallel Imaging Survey. I. Survey Design and Initial Results

Authors: Takahiro Morishita, Charlotte A. Mason, Kimi C. Kreilgaard, Michele Trenti, Tommaso Treu, Benedetta Vulcani, Yechi Zhang, Abdurro'uf, Anahita Alavi, Hakim Atek, Yannick Bahe, Marusa Bradac, Larry D. Bradley, Andrew J. Bunker, Dan Coe, James Colbert, Viola Gelli, Matthew J. Hayes, Tucker Jones, Tadayuki Kodama, Nicha Leethochawalit, Zhaoran Liu, Matthew A. Malkan, Vihang Mehta, Benjamin Metha , et al. (10 additional authors not shown)

Abstract: We introduce the Bias-free Extragalactic Analysis for Cosmic Origins with NIRCam (BEACON) survey, a JWST Cycle2 program allocated up to 600 pure-parallel hours of observations. BEACON explores high-latitude areas of the sky with JWST/NIRCam over $\sim100$ independent sightlines, totaling $\sim0.3$deg$^2$, reaching a median F444W depth of $\approx28.2$AB mag (5$σ$). Based on existing JWST observati… ▽ More We introduce the Bias-free Extragalactic Analysis for Cosmic Origins with NIRCam (BEACON) survey, a JWST Cycle2 program allocated up to 600 pure-parallel hours of observations. BEACON explores high-latitude areas of the sky with JWST/NIRCam over $\sim100$ independent sightlines, totaling $\sim0.3$deg$^2$, reaching a median F444W depth of $\approx28.2$AB mag (5$σ$). Based on existing JWST observations in legacy fields, we estimate that BEACON will photometrically identify 25--150 galaxies at $z>10$ and 500--1000 at $z\sim7$--10 uniquely enabled by an efficient multiple filter configuration spanning $0.9$--5.0$μ$m. The expected sample size of $z>10$ galaxies will allow us to obtain robust number density estimates and to discriminate between different models of early star formation. In this paper, we present an overview of the survey design and initial results using the first 19 fields. We present 129 galaxy candidates at $z>7$ identified in those fields, including 11 galaxies at $z>10$ and several UV-luminous ($M_{\rm UV}<-21$mag) galaxies at $z\sim8$. The number densities of $z<13$ galaxies inferred from the initial fields are overall consistent with those in the literature. Despite reaching a considerably large volume ($\sim10^5$Mpc$^3$), however, we find no galaxy candidates at $z>13$, providing us with a complimentary insight into early galaxy evolution with minimal cosmic variance. We publish imaging and catalog data products for these initial fields. Upon survey completion, all BEACON data will be coherently processed and distributed to the community along with catalogs for redshift and other physical quantities. △ Less

Submitted 9 December, 2024; v1 submitted 5 December, 2024; originally announced December 2024.

Comments: Submitted to ApJ; DR1 data release will be made on the team website (https://beacon-jwst.github.io); Fig. 8 has been updated

UVCANDELS: Catalogs of photometric redshifts and galaxy physical properties

Authors: Vihang Mehta, Marc Rafelski, Ben Sunnquist, Harry I. Teplitz, Claudia Scarlata, Xin Wang, Adriano Fontana, Nimish P. Hathi, Kartheik G. Iyer, Anahita Alavi, James Colbert, Norman Grogin, Anton Koekemoer, Kalina V. Nedkova, Matthew Hayes, Laura Prichard, Brian Siana, Brent M. Smith, Rogier Windhorst, Teresa Ashcraft, Micaela Bagley, Ivano Baronchelli, Guillermo Barro, Alex Blanche, Adam Broussard , et al. (54 additional authors not shown)

Abstract: The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides deep HST F275W and F435W imaging over four CANDELS fields (GOODS-N, GOODS-S, COSMOS, and EGS). We combine this newly acquired UV imaging with existing HST imaging from CANDELS as well as existing ancillary data to obtain robust photometric redshifts and reliable estimat… ▽ More The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides deep HST F275W and F435W imaging over four CANDELS fields (GOODS-N, GOODS-S, COSMOS, and EGS). We combine this newly acquired UV imaging with existing HST imaging from CANDELS as well as existing ancillary data to obtain robust photometric redshifts and reliable estimates for galaxy physical properties for over 150,000 galaxies in the $\sim$430 arcmin$^2$ UVCANDELS area. Here, we leverage the power of the new UV photometry to not only improve the photometric redshift measurements in these fields, but also constrain the full redshift probability distribution combining multiple redshift fitting tools. Furthermore, using the full UV-to-IR photometric dataset, we measure the galaxy physical properties by fitting templates from population synthesis models with two different parameterizations (flexible and fixed-form) of the star-formation histories (SFHs). Compared to the flexible SFH parametrization, we find that the fixed-form SFHs systematically underestimate the galaxy stellar masses, both at the low- ($\lesssim10^9 M_\odot$) and high- ($\gtrsim10^{10} M_\odot$) mass end, by as much as $\sim0.5$ dex. This underestimation is primarily due the limited ability of fixed-form SFH parameterization to simultaneously capture the chaotic nature of star-formation in these galaxies. △ Less

Submitted 21 October, 2024; originally announced October 2024.

Comments: 22 pages, 6 figures; accepted to ApJS; catalogs available via MAST

The MUSE Ultra Deep Field (MUDF) VII. Probing high-redshift gas structures in the surroundings of ALMA-identified massive dusty galaxies

Authors: A. Pensabene, M. Galbiati, M. Fumagalli, M. Fossati, I. Smail, M. Rafelski, M. Revalski, F. Arrigoni-Battaia, A. Beckett, S. Cantalupo, R. Dutta, E. Lusso, T. Lazeyras, G. Quadri, D. Tornotti

Abstract: We present new ALMA continuum and spectral observations of the MUSE Ultra Deep Field (MUDF), a $2\times 2$ arcmin$^2$ region with ultradeep multiwavelength imaging and spectroscopy hosting two bright $z\approx 3.22$ quasars used to study intervening gas structures in absorption. Through a blind search for dusty galaxies, we identified a total of seven high-confidence sources, six of which with sec… ▽ More We present new ALMA continuum and spectral observations of the MUSE Ultra Deep Field (MUDF), a $2\times 2$ arcmin$^2$ region with ultradeep multiwavelength imaging and spectroscopy hosting two bright $z\approx 3.22$ quasars used to study intervening gas structures in absorption. Through a blind search for dusty galaxies, we identified a total of seven high-confidence sources, six of which with secure spectroscopic redshifts. We estimate galaxy dust and stellar masses ($M_{\rm dust}\simeq 10^{7.8-8.6}\,M_{\odot}$, $M_{\star}\simeq 10^{10.2-10.7}\,M_{\odot}$), as well as star formation rates (${\rm SFR}\simeq 10^{1.2-2.0}\,M_{\odot}\,{\rm yr^{-1}} $) which show that most of these galaxies are massive and dust-obscured similar to coeval (sub-)millimeter galaxies. All six spectroscopically-confirmed galaxies are within $500~\rm km~s^{-1}$ of metal absorption lines observed in the quasar sightlines, corresponding to $100\%$ association rate. We also find that four of these galaxies belong to groups in which they are among the most massive members. Within the multiple group galaxies associated to the same absorption system, the ALMA sources are not always the closest in projection, but they are often aligned with the gaseous structures in velocity space. This suggests that these massive galaxies occupy the center of the potential well of the gas structures traced in absorption. However, albeit the low number density of sources identified with ALMA, our study may indicate that absorbers seem to infrequently originate in the inner circumgalactic medium of these galaxies. Instead, they appear to be better tracers of the gas distributed in the large-scale structure that host them. △ Less

Submitted 8 October, 2024; originally announced October 2024.

Comments: 13 pages, 9 figures, 1 Appendix. Submitted to A&A

Journal ref: A&A 696, A33 (2025)

Metal line emission around z<1 galaxies

Authors: Rajeshwari Dutta, Michele Fumagalli, Matteo Fossati, Marc Rafelski, Mitchell Revalski, Fabrizio Arrigoni Battaia, Valentina D'Odorico, Celine Peroux, Laura J. Prichard, A. M. Swinbank

Abstract: We characterize, for the first time, the average extended emission in multiple lines ([OII], [OIII], and Hbeta) around a statistical sample of 560 galaxies at z~0.25-0.85. By stacking the Multi Unit Spectroscopic Explorer (MUSE) 3D data from two large surveys, the MUSE Analysis of Gas around Galaxies (MAGG) and the MUSE Ultra Deep Field (MUDF), we detect significant [OII] emission out to ~40 kpc,… ▽ More We characterize, for the first time, the average extended emission in multiple lines ([OII], [OIII], and Hbeta) around a statistical sample of 560 galaxies at z~0.25-0.85. By stacking the Multi Unit Spectroscopic Explorer (MUSE) 3D data from two large surveys, the MUSE Analysis of Gas around Galaxies (MAGG) and the MUSE Ultra Deep Field (MUDF), we detect significant [OII] emission out to ~40 kpc, while [OIII] and Hbeta emission is detected out to ~30 kpc. Via comparisons with the nearby average stellar continuum emission, we find that the line emission at 20-30 kpc likely arises from the disk-halo interface. Combining our results with that of our previous study at z~1, we find that the average [OII] surface brightness increases independently with redshift over z~0.4-1.3 and with stellar mass over M* ~10^{6-12} Msun, which is likely driven by the star formation rate as well as the physical conditions of the gas. By comparing the observed line fluxes with photoionization models, we find that the ionization parameter declines with distance, going from log q (cm/s) ~7.7 at <=5 kpc to ~7.3 at 20-30 kpc, which reflects a weaker radiation field in the outer regions of galaxies. The gas-phase metallicity shows no significant variation over 30 kpc, with a metallicity gradient of ~0.003 dex/kpc, which indicates an efficient mixing of metals on these scales. Alternatively, there could be a significant contribution from shocks and diffuse ionized gas to the line emission in the outer regions. △ Less

Submitted 3 September, 2024; originally announced September 2024.

Comments: 9 pages, 6 figures, A&A in press

The stellar population of a $z\sim3.25$ Ly$α$ emitting group associated with a damped Ly$α$ absorber

Authors: Giulia Pruto, Michele Fumagalli, Marc Rafelski, Mitchell Revalski, Matteo Fossati, Ruari Mackenzie, Tom Theuns

Abstract: We present near-infrared observations, acquired with the Wide Field Camera 3 (WFC3) on board of the Hubble Space Telescope (HST), of a Ly$α$ double-clumped emitting nebula at $z \approx 3.25$ associated with a damped Ly$α$ absorber (DLA). With the WFC3/F160W data we observe the stellar continuum around $3600$ $\mathring{\rm A}$ in the rest frame for a galaxy embedded in the West clump of the nebul… ▽ More We present near-infrared observations, acquired with the Wide Field Camera 3 (WFC3) on board of the Hubble Space Telescope (HST), of a Ly$α$ double-clumped emitting nebula at $z \approx 3.25$ associated with a damped Ly$α$ absorber (DLA). With the WFC3/F160W data we observe the stellar continuum around $3600$ $\mathring{\rm A}$ in the rest frame for a galaxy embedded in the West clump of the nebula, $G_{\rm W}$, for which we estimate a star formation rate SFR$_{G_{\rm W}} = 5.0 \pm 0.4$ M$_\odot$ yr$^{-1}$ and maximum stellar mass M$_{G_{\rm W}} < 9.9 \pm 0.7 \times 10^9$ M$_\odot$. With the enhanced spatial resolution of HST, we discover the presence of an additional faint source, $G_{\rm E}$, in the center of the East clump, with a star formation rate of SFR$_{G_{\rm E}} = 0.70 \pm 0.20$ M$_\odot$ yr$^{-1}$ and maximum stellar mass M$_{G_{\rm E}} < 1.4 \pm 0.4 \times 10^9$ M$_\odot$. We show that the Ly$α$ emission in the two clumps can be explained by recombination following in-situ photoionization by the two galaxies, assuming escape fractions of ionizing photons of $\lesssim 0.24$ for $G_{\rm W}$ and $\lesssim 0.34$ for $G_{\rm E}$. The fact that $G_{\rm W}$ is offset by $\approx 8$ kpc from the West clump does not fully rule out the presence of additional fainter star-forming sources that would further contribute to the photon budget inside this $\approx 10^{12}$ M$_\odot$ galaxy group that extends over a region encompassing over $30 \times 50$ kpc. △ Less

Submitted 3 September, 2024; originally announced September 2024.

Comments: 9 pages, 7 figures, 1 table. Re-submitted to A&A

Journal ref: A&A 691, A222 (2024)

The MUSE Ultra Deep Field (MUDF). VI. The relationship between galaxy properties and metals in the circumgalactic medium

Authors: Alexander Beckett, Marc Rafelski, Mitchell Revalski, Michele Fumagalli, Matteo Fossati, Kalina Nedkova, Rajeshwari Dutta, Rich Bielby, Sebastiano Cantalupo, Prakita Dayal, Valentina D'Odorico, Marta Galbiati, Céline Péroux

Abstract: We present intial results associating galaxies in the MUSE Ultra Deep Field (MUDF) with gas seen in absorption along the line-of-sight to two bright quasars in this field, to explore the dependence of metals in the circumgalactic medium (CGM) on galaxy properties. The MUDF includes $\sim$140h of VLT/MUSE data and 90 orbits of HST/G141M grism observations alongside VLT/UVES spectroscopy of the two… ▽ More We present intial results associating galaxies in the MUSE Ultra Deep Field (MUDF) with gas seen in absorption along the line-of-sight to two bright quasars in this field, to explore the dependence of metals in the circumgalactic medium (CGM) on galaxy properties. The MUDF includes $\sim$140h of VLT/MUSE data and 90 orbits of HST/G141M grism observations alongside VLT/UVES spectroscopy of the two quasars and several bands of HST imaging. We compare the metal absorption around galaxies in this field as a function of impact parameter, azimuthal angle and galaxy metallicity across redshifts 0.5 $<$ z $<$ 3.2. Due to the depth of our data and a large field-of-view, our analysis extends to low stellar masses ($<$ $10^{7}$ M$_{\odot}$) and high impact parameters ($>$ 600 kpc). We find a correlation between absorber equivalent width and number of nearby galaxies, but do not detect a significant anti-correlation with impact parameter. Our full sample does not show any significant change in absorber incidence as a function of azimuthal angle. However, we do find a bimodality in the azimuthal angle distribution of absorption at small impact parameters ($<$2 r$_{vir}$) and around highly-star-forming galaxies, possibly indicating disk-like accretion and biconical outflows. Finally, we do not detect any systematic deviation from the fundamental metallicity relation (FMR) among galaxies with detected absorption. This work is limited by gaps in the wavelength coverage of our current data; broader-wavelength observations with JWST will allow us to unlock the full potential of the MUDF for studying the CGM. △ Less

Submitted 21 August, 2024; originally announced August 2024.

Comments: Accepted for publication in The Astrophysical Journal. 31 pages, 17 figures

AstroSat UV Deep Field South -- I. Far and Near-ultraviolet Source Catalog of the GOODS South region

Authors: Kanak Saha, Soumil Maulick, Pushpak Pandey, Souradeep Bhattacharya, Anshuman Borgohain, Chayan Mondal, Marc Rafelski, Manish Kataria, Harry I. Teplitz, Shyam N. Tandon, Rogier A. Windhorst, Bruce G. Elmegreen, Edmund Christian Herenz, Michael Rutkowski

Abstract: We present the AstroSat UV Deep Field South (AUDFs), an imaging survey using the wide-field Ultraviolet Imaging Telescope on board AstroSat. AUDFs covers $\sim 236$ arcmin$^{2}$ of the sky area, including the Great Observatories Origins Deep Survey (GOODS) South field in F154W and N242W filters. The deep and shallow parts of AUDFs have exposure time $\sim 62000$ and $\sim31000$ sec respectively, i… ▽ More We present the AstroSat UV Deep Field South (AUDFs), an imaging survey using the wide-field Ultraviolet Imaging Telescope on board AstroSat. AUDFs covers $\sim 236$ arcmin$^{2}$ of the sky area, including the Great Observatories Origins Deep Survey (GOODS) South field in F154W and N242W filters. The deep and shallow parts of AUDFs have exposure time $\sim 62000$ and $\sim31000$ sec respectively, in the F154W filter, while in the N242W filter, they are $\sim 64000$ and $\sim34000$ sec. These observations reached a $3σ$ depth of 27.2 and 27.7 AB mag with a $50\%$ completeness limit of 27 and 27.6 AB mag in the F154W and N242W filters, respectively. With the acquired depth, AUDFs is the deepest far and near-UV imaging data covering the largest area known to date at 1.2" - 1.6" spatial resolution. Two primary catalogs were constructed for the F154W and N242W filters, each containing 13495 and 19374 sources brighter than the 3$σ$ detection limit, respectively. Our galaxy counts power-law slope $\sim0.43$~dex~mag$^{-1}$ in the N242W filter matches well with HST/WFC3/UVIS observations. A wide range of extra-galactic science can be achieved with this unique data, such as providing a sample of galaxies emitting ionizing photons in the redshift range $z \sim 1 - 3$ and beyond; constraining the UV luminosity function, investigating the extended-UV (XUV) emission around star-forming galaxies and UV morphologies for $z < 1$. The UV catalog will enhance the legacy value of the existing optical/IR imaging and spectroscopic observations from ground and space-based telescopes on the GOODS South field. △ Less

Submitted 7 August, 2024; originally announced August 2024.

Comments: 26 pages, 19 figures, 7 tables, accepted for publication in the Astrophysical Journal Supplement Series, comments are welcome

An HI-absorption-selected cold rotating disk galaxy at $z\approx2.193$

Authors: B. Kaur, N. Kanekar, M. Neeleman, M. Rafelski, J. X. Prochaska, R. Dutta

Abstract: We have used the Atacama Large Millimeter/submillimeter Array (ALMA) to map CO(3-2) emission from a galaxy, DLA-B1228g, associated with the high-metallicity damped Lyman-$α$ absorber at $z \approx 2.1929$ towards the QSO PKS B1228-113. At an angular resolution of $\approx0.32''\times0.24''$, DLA-B1228g shows extended CO(3-2) emission with a deconvolved size of $\approx0.78''\times0.18''$, i.e. a s… ▽ More We have used the Atacama Large Millimeter/submillimeter Array (ALMA) to map CO(3-2) emission from a galaxy, DLA-B1228g, associated with the high-metallicity damped Lyman-$α$ absorber at $z \approx 2.1929$ towards the QSO PKS B1228-113. At an angular resolution of $\approx0.32''\times0.24''$, DLA-B1228g shows extended CO(3-2) emission with a deconvolved size of $\approx0.78''\times0.18''$, i.e. a spatial extent of $\approx6.4$ kpc. We detect extended stellar emission from DLA-B1228g in a Hubble Space Telescope Wide Field Camera 3 F160W image, and find that H$α$ emission is detected in a Very Large Telescope SINFONI image from only one side of the galaxy. While the clumpy nature of the F160W emission and the offset between the kinematic and physical centers of the CO(3-2) emission are consistent with a merger scenario, this appears unlikely due to the lack of strong H$α$ emission, the symmetric double-peaked CO(3-2) line profile, the high molecular gas depletion timescale, and the similar velocity dispersions in the two halves of the CO(3-2) image. Kinematic modelling reveals that the CO(3-2) emission is consistent with arising from an axisymmetric rotating disk, with an exponential profile, a rotation velocity of $v_{rot}=328\pm7$ km s$^{-1}$, and a velocity dispersion of $σ_{v}=62\pm7$ km s$^{-1}$. The high value of the ratio $v_{rot}/σ_v$, $\approx5.3$, implies that DLA-B1228g is a rotation-dominated cold disk galaxy, the second case of a high-$z$ HI-absorption-selected galaxy identified with a cold rotating disk. We obtain a dynamical mass of $M_{dyn}= (1.5\pm0.1)\times10^{11}~M_\odot$, similar to the molecular gas mass of $\approx10^{11} M_\odot$ inferred from earlier CO(1-0) studies; this implies that the galaxy is baryon-dominated in its inner regions. △ Less

Submitted 1 August, 2024; originally announced August 2024.

Comments: 13 pages, 5 figures and 2 tables. Accepted for publication in ApJL

Determining the Extents, Geometries, and Kinematics of Narrow-Line Region Outflows in Nearby Seyfert Galaxies

Authors: Garrett E. Polack, Mitchell Revalski, D. Michael Crenshaw, Travis C. Fischer, Henrique R. Schmitt, Steven B. Kraemer, Beena Meena, Marc Rafelski

Abstract: Outflowing gas from supermassive black holes in the centers of active galaxies has been postulated as a major contributor to galactic evolution. To explore the interaction between narrow-line region (NLR) outflows and their host galaxies, we use Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) spectra and Wide Field Camera 3 (WFC3) images of 15 nearby (z < 0.02) active gala… ▽ More Outflowing gas from supermassive black holes in the centers of active galaxies has been postulated as a major contributor to galactic evolution. To explore the interaction between narrow-line region (NLR) outflows and their host galaxies, we use Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) spectra and Wide Field Camera 3 (WFC3) images of 15 nearby (z < 0.02) active galactic nuclei (AGN) to determine the extents and geometries of their NLRs. We combine new HST WFC3 continuum and [O III] $λ$5007A images of 11 AGN with 4 archival AGN to match existing spectra from HST STIS. For the 6 AGN with suitable long-slit coverage of their NLRs, we use isophotal fitting of ground-based images, continuum-subtracted [O III] images, and the STIS spectra, to resolve, measure, and de-project the gas kinematics to the plane of the host galaxy disk and distinguish NLR outflows from galaxy rotation and/or kinematically disturbed gas. We find an average [O III] extent of $\sim$680pc with a correlation between gas extent and [O III] luminosity of R$_\mathrm{[O III]}$ $\propto$ L$_{\text{[O III]}}^{0.39}$. The measured extents depend strongly on the depth of the [O III] images, highlighting the importance of adopting uniform thresholds when analyzing scaling relationships. The outflows reach from 39-88% of the full NLR extents, and we find that all 6 of the AGN with STIS coverage of their entire NLRs show strong kinematic evidence for outflows, despite previous uncertainty for these AGN. This suggests that NLR outflows are ubiquitous in moderate luminosity AGN and that standard criteria for kinematic modeling are essential for identifying outflows. △ Less

Submitted 24 September, 2024; v1 submitted 24 July, 2024; originally announced July 2024.

Comments: Accepted for publication in ApJ on July 9, 2024. The paper has 21 pages, 10 figures, and 6 tables. Version two includes minor corrections to match the journal publication. The calibrated data are available through MAST at: https://archive.stsci.edu/hlsp/nlr-agn

High-definition imaging of a filamentary connection between a close quasar pair at z=3

Authors: Davide Tornotti, Michele Fumagalli, Matteo Fossati, Alejandro Benitez-Llambay, David Izquierdo-Villalba, Andrea Travascio, Fabrizio Arrigoni Battaia, Sebastiano Cantalupo, Alexander Beckett, Silvia Bonoli, Pratika Dayal, Valentina D'Odorico, Rajeshwari Dutta, Elisabeta Lusso, Celine Peroux, Marc Rafelski, Mitchell Revalski, Daniele Spinoso, Mark Swinbank

Abstract: Filaments connecting halos are a long-standing prediction of cold dark matter theories. We present a detection of the cosmic web emission connecting two quasar-host galaxies at redshift z ~3.22 in the MUSE Ultra Deep Field (MUDF). The very deep observations unlock a high-definition view of the filament morphology, a measure of the transition radius between the intergalactic and circumgalactic medi… ▽ More Filaments connecting halos are a long-standing prediction of cold dark matter theories. We present a detection of the cosmic web emission connecting two quasar-host galaxies at redshift z ~3.22 in the MUSE Ultra Deep Field (MUDF). The very deep observations unlock a high-definition view of the filament morphology, a measure of the transition radius between the intergalactic and circumgalactic medium, and the characterization of the surface brightness profiles along the filament and in the transverse direction. Through systematic comparisons with simulations, we validate the filaments' typical density predicted in the current cold dark-matter model. Our analysis of the MUDF field, an excellent laboratory for quantitatively studying filaments in emission, opens a new avenue to constrain the physical properties of the cosmic web and to trace the distribution of dark matter on large scales. △ Less

Submitted 29 January, 2025; v1 submitted 24 June, 2024; originally announced June 2024.

Comments: Published in Nature Astronomy on January 29th, 2025 (online); 4 main figures and 1 table; 7 extended data figures; 1 extended data table. See https://www.nature.com/articles/s41550-024-02463-w

Bulge+disc decomposition of HFF and CANDELS galaxies: UVJ diagrams and stellar mass-size relations of galaxy components at $0.2 \leq z \leq 1.5$

Authors: Kalina V. Nedkova, Boris Häußler, Danilo Marchesini, Gabriel B. Brammer, Adina D. Feinstein, Evelyn J. Johnston, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Nicholas S. Martis, Adam Muzzin, Marc Rafelski, Heath V. Shipley, Rosalind E. Skelton, Mauro Stefanon, Arjen van der Wel, Katherine E. Whitaker

Abstract: Using deep imaging from the CANDELS and HFF surveys, we present bulge+disc decompositions with GalfitM for $\sim$17,000 galaxies over $0.2 \leq z\leq 1.5$. We use various model parameters to select reliable samples of discs and bulges, and derive their stellar masses using an empirically calibrated relation between mass-to-light ratio and colour. Across our entire redshift range, we show that disc… ▽ More Using deep imaging from the CANDELS and HFF surveys, we present bulge+disc decompositions with GalfitM for $\sim$17,000 galaxies over $0.2 \leq z\leq 1.5$. We use various model parameters to select reliable samples of discs and bulges, and derive their stellar masses using an empirically calibrated relation between mass-to-light ratio and colour. Across our entire redshift range, we show that discs follow stellar mass-size relations that are consistent with those of star-forming galaxies, suggesting that discs primarily evolve via star formation. In contrast, the stellar mass-size relations of bulges are mass-independent. Our novel dataset further enables us to separate components into star-forming and quiescent based on their specific star formation rates. We find that both star-forming discs and star-forming bulges lie on stellar mass-size relations that are similar to those of star-forming galaxies, while quiescent discs are typically smaller than star-forming discs and lie on steeper relations, implying distinct evolutionary mechanisms. Similar to quiescent galaxies, quiescent bulges show a flattening in the stellar mass-size relation at $\sim$10$^{10}$M$_\odot$, below which they show little mass dependence. However, their best-fitting relations have lower normalisations, indicating that at a given mass, bulges are smaller than quiescent galaxies. Finally, we obtain rest-frame colours for individual components, showing that bulges typically have redder colours than discs, as expected. We visually derive UVJ criteria to separate star-forming and quiescent components and show that this separation agrees well with component colour. HFF bulge+disc decomposition catalogues used for these analyses are publicly released with this paper. △ Less

Submitted 20 June, 2024; originally announced June 2024.

Comments: 30 pages, 18 figures, and 6 tables. Resubmitted to MNRAS after addressing a thorough and constructive referee report

Challenging the LyC-Ly$α$ relation: strong Ly$α$ emitters without LyC leakage at z $\sim$ 2.3

Authors: Annalisa Citro, Claudia M. Scarlata, Kameswara B. Mantha, Liliya R. Williams, Marc Rafelski, Mitchell Revalski, Matthew J. Hayes, Alaina Henry, Michael J. Rutkowski, Harry I. Teplitz, Andrea Grazian, Anahita Alavi

Abstract: The escape fraction of LyC ionizing radiation ($f_{lyc}$) is crucial for understanding reionization, yet difficult to measure at $z \gtrsim 4$. Recently, studies have focused on calibrating indirect indicators of $f_{lyc}$ at $z \sim 0.3$, finding that $Lyα$ is closely linked to it. What is still unclear is whether the LyC $-$ $Lyα$ relation evolves with redshift, and if $Lyα$ is truly applicable… ▽ More The escape fraction of LyC ionizing radiation ($f_{lyc}$) is crucial for understanding reionization, yet difficult to measure at $z \gtrsim 4$. Recently, studies have focused on calibrating indirect indicators of $f_{lyc}$ at $z \sim 0.3$, finding that $Lyα$ is closely linked to it. What is still unclear is whether the LyC $-$ $Lyα$ relation evolves with redshift, and if $Lyα$ is truly applicable as an $f_{lyc}$ indicator during the reionization epoch. In this study, we investigate seven $-21 \lesssim M_{UV} \lesssim-19$ gravitationally lensed galaxies from the BELLS GALLERY Survey at $z\sim2.3$. Our targets have rest-frame $Lyα$ equivalent widths between 40 Å and 200 Å and low dust content ($-2.4 \lesssim β\lesssim -2.0$), both indicative of high LyC escape. Surprisingly, direct estimates of $f_{lyc}$ using Hubble Space Telescope imaging with F275W and F225W reveal that our targets are not LyC emitters, with an absolute $f_{lyc} < 13 \%$ (assuming the median IGM transmission). The low $f_{lyc}$, coupled with the high $Lyα$ equivalent width and escape fraction, could potentially be attributed to the redshift evolution of the neutral hydrogen column density and dust content, as well as covering fractions of optically thick gas below 1 in high redshift galaxies. Additionally, our analysis suggests that the emission for each lensed component is uniformly absorbed. Our results challenge the validity of the extrapolation of $z\sim0$ Ly$α$-based LyC indirect estimators into the reionization epoch. △ Less

Submitted 7 May, 2025; v1 submitted 11 June, 2024; originally announced June 2024.

Comments: 23 Pages, 11 Figures. Accepted for publication in ApJ

Galaxy Rest-Frame UV Colors at z ~ 2-4 with HST UVCANDELS

Authors: Alexa Morales, Steven Finkelstein, Micaela Bagley, Anahita Alavi, Norman Grogin, Nimish Hathi, Anton Koekemoer, Kalina Nedkova, Laura Prichard, Marc Rafelski, Ben Sunnquist, Sina Taamoli, Harry Teplitz, Xin Wang, Rogier Windhorst, L. Y. Aaron Yung

Abstract: We present an analysis of rest-frame UV colors of 17,243 galaxies at $z\sim2-4$ in the HST UVCANDELS fields: GOODS-N, GOODS-S, COSMOS, and EGS. Here, we study the rest-frame UV spectral slope, $β$, measured via model spectra obtained via spectral energy distribution (SED) fitting, $β_{SED}$, and explore its correlation with various galaxy parameters (photometric redshift, UV magnitude, stellar mas… ▽ More We present an analysis of rest-frame UV colors of 17,243 galaxies at $z\sim2-4$ in the HST UVCANDELS fields: GOODS-N, GOODS-S, COSMOS, and EGS. Here, we study the rest-frame UV spectral slope, $β$, measured via model spectra obtained via spectral energy distribution (SED) fitting, $β_{SED}$, and explore its correlation with various galaxy parameters (photometric redshift, UV magnitude, stellar mass, dust attenuation, star formation rate [SFR], and specific SFR) obtained via SED fitting with Dense Basis. We also obtain measurements for $β$ via photometric power-law fitting and compare them to our SED-fit-based results, finding good agreement on average. While we find little evolution in $β$ with redshift from $z=2-4$ for the full population, there are clear correlations between $β$ (and related parameters) when binned by stellar mass. For this sample, lower stellar mass galaxies (log[$M_*$] = 7.5-8.5 $M_\odot$) are typically bluer ($β_{SED}=-2.0\pm 0.2$ / $β_{PL} = -2.1\pm0.4$), fainter ($MUV = -17.8^{+0.7}_{-0.6}$) less dusty ($A{v}=0.4\pm0.1$ mag), exhibit lower rates of star formation (log[SFR]=$0.1\pm0.2 M_\odot/$ yr) and higher specific star formation rates (log[sSFR]=$-8.2\pm0.2 \ \mathrm{yr}^{-1}$) than their high-mass counterparts. Higher-mass galaxies (log[$M_*$] $=10.0-12.0 \ M_\odot$) are on average redder ($β_{SED}=-0.9^{+0.8}_{-0.5}$ / $β_{PL}=-1.0^{+0.8}_{-0.5}$), brighter ($MUV=-19.6^{+1.0}_{-1.2}$), dustier ($Av = 0.9^{+0.5}_{-0.4}$ mag), have higher SFRs (log[SFR]=$1.2^{+0.6}_{-1.1} M_\odot$ yr), and lower sSFRs (log[sSFR]=$-9.1^{+0.5}_{-1.1} {yr}^{-1}$). This study's substantial sample size provides a benchmark for demonstrating that the rest-frame UV spectral slope correlates with stellar mass-dependent galaxy characteristics at $z\sim2-4$, a relationship less discernible with smaller datasets typically available at higher redshifts. △ Less

Submitted 22 May, 2025; v1 submitted 31 May, 2024; originally announced May 2024.

Comments: 13 pages, 5 tables, 7 figures, published in ApJ

UVCANDELS: The role of dust on the stellar mass-size relation of disk galaxies at 0.5 $\leq z \leq$ 3.0

Authors: Kalina V. Nedkova, Marc Rafelski, Harry I. Teplitz, Vihang Mehta, Laura DeGroot, Swara Ravindranath, Anahita Alavi, Alexander Beckett, Norman A. Grogin, Boris Häußler, Anton M. Koekemoer, Grecco A. Oyarzún, Laura Prichard, Mitchell Revalski, Gregory F. Snyder, Ben Sunnquist, Xin Wang, Rogier A. Windhorst, Nima Chartab, Christopher J. Conselice, Yicheng Guo, Nimish Hathi, Matthew J. Hayes, Zhiyuan Ji, Keunho J. Kim , et al. (8 additional authors not shown)

Abstract: We use the Ultraviolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields (UVCANDELS) to measure half-light radii in the rest-frame far-UV for $\sim$16,000 disk-like galaxies over $0.5\leq z \leq 3$. We compare these results to rest-frame optical sizes that we measure in a self-consistent way and find that the stellar mass-size relation of disk galaxies is steeper… ▽ More We use the Ultraviolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields (UVCANDELS) to measure half-light radii in the rest-frame far-UV for $\sim$16,000 disk-like galaxies over $0.5\leq z \leq 3$. We compare these results to rest-frame optical sizes that we measure in a self-consistent way and find that the stellar mass-size relation of disk galaxies is steeper in the rest-frame UV than in the optical across our entire redshift range. We show that this is mainly driven by massive galaxies ($\gtrsim10^{10}$M$_\odot$), which we find to also be among the most dusty. Our results are consistent with the literature and have commonly been interpreted as evidence of inside-out growth wherein galaxies form their central structures first. However, they could also suggest that the centers of massive galaxies are more heavily attenuated than their outskirts. We distinguish between these scenarios by modeling and selecting galaxies at $z=2$ from the VELA simulation suite in a way that is consistent with UVCANDELS. We show that the effects of dust alone can account for the size differences we measure at $z=2$. This indicates that, at different wavelengths, size differences and the different slopes of the stellar mass-size relation do not constitute evidence for inside-out growth. △ Less

Submitted 28 June, 2024; v1 submitted 17 May, 2024; originally announced May 2024.

Comments: Accepted for publication in ApJ. 22 pages, 12 figures, and 4 tables

Emission-line galaxies at $z\sim1$ from near-IR HST Slitless Spectroscopy: metallicities, star formation rates and redshift confirmations from VLT/FORS2 spectroscopy

Authors: K. Boyett, A. J. Bunker, J Chevallard, A. J. Battisti, A. L. Henry, S. Wilkins, M. A. Malkan, J. Caruana, H. Atek, I. Baronchelli, J. Colbert, Y. S. Dai, Jonathan. P. Gardner, M. Rafelski, C. Scarlata, H. I. Teplitz, X. Wang

Abstract: We follow up emission line galaxies identified through the near-infrared slitless HST/WFC3 WISP survey with VLT/FORS2 optical spectroscopy. Over 4 WISP fields, we targetted 85 of 138 line emission objects at $0.4<z<2$ identified in WFC3 spectroscopy. Half the galaxies are fainter than $H_{AB}=24$mag, and would not have been included in many well-known surveys based on broad-band magnitude selectio… ▽ More We follow up emission line galaxies identified through the near-infrared slitless HST/WFC3 WISP survey with VLT/FORS2 optical spectroscopy. Over 4 WISP fields, we targetted 85 of 138 line emission objects at $0.4<z<2$ identified in WFC3 spectroscopy. Half the galaxies are fainter than $H_{AB}=24$mag, and would not have been included in many well-known surveys based on broad-band magnitude selection. We confirm 95% of the initial WFC3 grism redshifts in the 38 cases where we detect lines in FORS2 spectroscopy. However, for targets which exhibited a single emission line in WFC3, up to 65% at $z<1.28$ did not have expected emission lines detected in FORS2 and hence may be spurious (although this false-detection rate improves to 33% using the latest public WISP emission line catalogue). From the Balmer decrement the extinction of the WISP galaxies is consistent with $A($H$α)=1$mag. From SED fits to multi-band photometry including Spitzer $3.6μ$m, we find a median stellar mass of $\log_{10}(M/M_{\odot})=8.94$. Our emission-line-selected galaxies tend to lie above the star-forming main sequence (i.e. higher specific star formation rates). Using [OIII], [OII] and H$β$ lines to derive gas-phase metallicities, we find typically sub-solar metallicities, decreasing with redshift. Our WISP galaxies lie below the $z=0$ mass-metallicity relation, and galaxies with higher star formation rates tend to have lower metallicity. Finally, we find a strong increase with redshift of the H$α$ rest-frame equivalent width in this emission-line selected sample, with higher $EW_0$ galaxies having larger [OIII]/H$β$ and O32 ratios on average, suggesting lower metallicity or higher ionisation parameter in these extreme emission line galaxies. △ Less

Submitted 30 August, 2024; v1 submitted 11 April, 2024; originally announced April 2024.

Comments: Accepted to MNRAS

WFC3 Infrared Spectroscopic Parallel (WISP) Survey: Photometric and Emission Line Data Release

Authors: A. J. Battisti, M. B. Bagley, M. Rafelski, I. Baronchelli, Y. S. Dai, A. L. Henry, H. Atek, J. Colbert, M. A. Malkan, P. J. McCarthy, C. Scarlata, B. Siana, H. I. Teplitz, A. Alavi, K. Boyett, A. J. Bunker, J. P. Gardner, N. P. Hathi, D. Masters, V. Mehta, M. Rutkowski, K. Shahinyan, B. Sunnquist, X. Wang

Abstract: We present reduced images and catalogues of photometric and emission line data ($\sim$230,000 and $\sim$8,000 sources, respectively) for the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. These data are made publicly available on the Mikulski Archive for Space Telescopes (MAST) and include reduced images from various facilities: ground-based $ugri$, HST WFC3, and Spitzer IRAC (Infrared Array… ▽ More We present reduced images and catalogues of photometric and emission line data ($\sim$230,000 and $\sim$8,000 sources, respectively) for the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. These data are made publicly available on the Mikulski Archive for Space Telescopes (MAST) and include reduced images from various facilities: ground-based $ugri$, HST WFC3, and Spitzer IRAC (Infrared Array Camera). Coverage in at least one additional filter beyond the WFC3/IR data are available for roughly half of the fields (227 out of 483), with $\sim$20% (86) having coverage in six or more filters from $u$-band to IRAC 3.6$μ$m (0.35-3.6$μ$m). For the lower spatial resolution (and shallower) ground-based and IRAC data, we perform PSF-matched, prior-based, deconfusion photometry (i.e., forced-photometry) using the TPHOT software to optimally extract measurements or upper limits. We present the methodology and software used for the WISP emission line detection and visual inspection. The former adopts a continuous wavelet transformation that significantly reduces the number of spurious sources as candidates before the visual inspection stage. We combine both WISP catalogues and perform SED fitting on galaxies with reliable spectroscopic redshifts and multi-band photometry to measure their stellar masses. We stack WISP spectra as functions of stellar mass and redshift and measure average emission line fluxes and ratios. We find that WISP emission line sources are typically `normal' star-forming galaxies based on the Mass-Excitation diagram ([OIII]/H$β$ vs. $M_\star$; $0.74<z_\mathrm{grism}<2.31$), the galaxy main sequence (SFR vs. $M_\star$; $0.30<z_\mathrm{grism}<1.45$), $S_{32}$ ratio vs. $M_\star$ ($0.30<z_\mathrm{grism}<0.73$), and $O_{32}$ and $R_{23}$ ratios vs. $M_\star$ ($1.27<z_\mathrm{grism}<1.45$). △ Less

Submitted 6 April, 2024; originally announced April 2024.

Comments: 36 pages, 21 figures, 17 tables. Accepted for publication in MNRAS. The WISP Photometric and Emission Line catalogues and reduced images are in the process of being added as HLSPs to the WISP MAST website (https://archive.stsci.edu/prepds/wisp/). Please email the first-author (provided in paper) to request access to files prior to the MAST release

Discovery of optically emitting circumgalactic nebulae around the majority of UV-luminous quasars at intermediate redshift

Authors: Sean D. Johnson, Zhuoqi Will Liu, Jennifer I. Li, Joop Schaye, Jenny E. Greene, Sebastiano Cantalupo, Gwen C. Rudie, Zhijie Qu, Hsiao-Wen Chen, Marc Rafelski, Sowgat Muzahid, Mandy C. Chen, Thierry Contini, Wolfram Kollatschny, Nishant Mishra, Michael Rauch, Patrick Petitjean, Fakhri S. Zahedy

Abstract: We report the discovery of large ionized, [O II] emitting circumgalactic nebulae around the majority of thirty UV luminous quasars at $z=0.4-1.4$ observed with deep, wide-field integral field spectroscopy (IFS) with the Multi-Unit Spectroscopy Explorer (MUSE) by the Cosmic Ultraviolet Baryon Survey (CUBS) and MUSE Quasar Blind Emitters Survey (MUSEQuBES). Among the 30 quasars, seven (23%) exhibit… ▽ More We report the discovery of large ionized, [O II] emitting circumgalactic nebulae around the majority of thirty UV luminous quasars at $z=0.4-1.4$ observed with deep, wide-field integral field spectroscopy (IFS) with the Multi-Unit Spectroscopy Explorer (MUSE) by the Cosmic Ultraviolet Baryon Survey (CUBS) and MUSE Quasar Blind Emitters Survey (MUSEQuBES). Among the 30 quasars, seven (23%) exhibit [O II] emitting nebulae with major axis sizes greater than 100 kpc, twenty greater than 50 kpc (67%), and 27 (90%) greater than 20 kpc. Such large, optically emitting nebulae indicate that cool, dense, and metal-enriched circumgalactic gas is common in the halos of luminous quasars at intermediate redshift. Several of the largest nebulae exhibit morphologies that suggest interaction-related origins. We detect no correlation between the sizes and cosmological dimming corrected surface brightnesses of the nebulae and quasar redshift, luminosity, black hole mass, or radio-loudness, but find a tentative correlation between the nebulae and rest-frame [O II] equivalent width in the quasar spectra. This potential trend suggests a relationship between ISM content and gas reservoirs on CGM scales. The [O II]-emitting nebulae around the $z\approx1$ quasars are smaller and less common than Ly$α$ nebulae around $z\approx3$ quasars. These smaller sizes can be explained if the outer regions of the Ly$α$ halos arise from scattering in more neutral gas, by evolution in the cool CGM content of quasar host halos, by lower-than-expected metallicities on $\gtrsim50$ kpc scales around $z\approx1$ quasars, or by changes in quasar episodic lifetimes between $z=3$ and $1$. △ Less

Submitted 3 April, 2024; v1 submitted 29 March, 2024; originally announced April 2024.

Comments: 18 pages, 5 figures, 2 tables. Accepted for publication in the Astrophysical Journal