arXiv subjects

M. E. Wisz

Publications and source records attributed to M. E. Wisz.

7 recordsLinked to original sources

arXiv2026

The GOGREEN Survey: AI Powered Deconvolution Lifts The Veil on Outside-in Environmental Quenching at z > 1

A powerful probe of the physical processes that quench star formation in dense environments is determining where within galaxies star formation is suppressed. At high redshift, the spatial resolution of multi-band imaging limits such measurements. We use deep-learning-based deconvolution to recover spatially resolved optical and near-infrared photometry for galaxies in nine GOGREEN clusters at 1<z<1.4, using customized models trained on HST and JWST imaging. Using resolved rest-frame UVJ colors, we classify galaxies by the star-forming states of their inner and outer regions into predominantly star-forming, predominantly quiescent, inside-quenched, or outside-quenched. We find that 24% of galaxies classified as quiescent from their integrated colors retain significant star formation. The predominantly quiescent fraction increases with stellar mass and is higher in clusters than in the field while the cluster quenched fraction excess is, when limiting to predominantly quenched galaxies, approximately 20%. Contrary to previous GOGREEN studies using integrated colors, we find this excess to be independent of stellar mass, demonstrating that partially quenched galaxies can bias measurements based on integrated colors. Among galaxies retaining significant star formation, outside-quenched galaxies are substantially more common than inside-quenched galaxies and have a fraction excess of (22.8+/-5.8)% in clusters relative to the field at low masses. This provides evidence that clusters preferentially suppress star formation in the outskirts of low-mass galaxies. Our results demonstrate the importance of spatially resolved classifications for interpreting environmental quenching at z~1 and the potential of deep-learning-based deconvolution to recover such information from large ground-based imaging datasets.

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arXiv2026

Spiral Morphology and Radial Migration: Kinematically heating, cooling, and cold

Transient spiral arms are known to drive radial redistribution of stars and thus could play a central role in shaping disk galaxies, including modifying, over time, the age, chemical, and kinematic (chrono-chemo-dynamic) distributions in the Milky Way. However, the physical factors governing the efficiency of such processes remain poorly understood. This paper investigates how the morphology of spiral arms -- the number, pitch angle, lifetime, and radial dependence of the pattern speed -- influences orbital redistribution through 'cold torquing' at the corotation resonance(s). Analytic expressions are derived for the maximum radial excursion of stars trapped at corotation that explicitly account for spiral morphology, predicting that the efficiency of cold torquing for a density-wave like spiral is greater for more open spiral patterns. Tracer-particle simulations confirm the analytic prediction, in both two- and three-dimensional galactic potentials. In contrast, spirals that have a radially dependent pattern speed such that they corotate with the disk at all radii exhibit the opposite behavior, with cold torquing becoming more efficient as the spiral winds to smaller pitch angles over time. This study further finds that resonant interactions from the same transient spiral causing cold torquing naturally also produces both kinematic heating and cooling of orbits away from corotation. These results demonstrate that spiral morphology alone cannot predict the efficiency of cold torquing and suggest that the relationship between spiral pitch angle and radial redistribution provides a potential diagnostic for distinguishing between competing theories of spiral structure.

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arXiv2026

MAGAZ3NE: Spatially Resolved Ages and Chemical Abundances of Ultra-Massive Quiescent Galaxies at z $\sim$ 3.5 using JWST/NIRSpec IFU

We present spatially-resolved measurements of stellar age, [Fe/H], and [$α$/Fe] in three ultra-massive ($\rm{log(M_{\ast}/M_{\odot})>11}$), compact ($\rm{R_e} \lesssim 2$ kpc) quiescent galaxies at $z\sim3.5$ using JWST/NIRSpec IFU spectroscopy. These observations provide the first spatially-resolved constraints on $α$-enhancement at this epoch, enabling a direct test of quenching mechanisms before late-time assembly processes such as mergers can erase chemical signatures. The central regions of all three galaxies show both uniformly young ages ($\approx0.6-0.7$ Gyr) and elevated [$α$/Fe] ($\approx0.2-0.5$), indicating rapid, enhanced star formation shortly before recent quenching. Beyond the cores, two galaxies display positive age gradients and negative [$α$/Fe] gradients, consistent with rapid merger-driven quenching, while the third shows a flat age profile indicative of uniform quenching. The [Fe/H] gradients are also consistent with these trends, though we note that the metallicities reported by codes using $α$-enhanced models differ significantly ($\approx0.2-0.4$ dex) from those reported using solar-scaled templates. These data demonstrate that quenching pathways are diverse by $z\sim3.5$, with rapid, merger-driven quenching already operating in a subset of massive quiescent galaxies in the first two billion years of cosmic time. Furthermore, these results establish that explicit treatment of $α$-enhancement is essential for interpreting the star-formation histories of the earliest quenched systems.

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arXiv2026

A massive and evolved slow-rotating galaxy in the early Universe

In the contemporary Universe, most galaxies are supported by ordered rotation, yet a significant subset of the most massive and quiescent systems are dominated by random stellar motions and classified as slow rotators. These galaxies are widely thought to arise through processes that remove angular momentum and erase disk-like structures, but when and how this transformation occurs remains uncertain. Slow rotators are expected to be rare at early cosmic times, and observational studies of massive galaxies at high redshift have so far revealed only rapidly rotating systems. Here we report James Webb Space Telescope near-infrared integral field spectroscopy of XMM-VID1-2075, a massive quiescent galaxy at $z=3.449$. The galaxy displays disturbed low-surface-brightness features and a low stellar spin parameter, $λ_{R_e} = 0.123^{+0.073}_{-0.023}$, consistent with dispersion-dominated kinematics. These results demonstrate that the formation of slow-rotating massive galaxies was already underway when the Universe was less than 2 Gyr old.

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arXiv2025

Excavating The Ruins: an Ancient $z=2.675$ Galaxy Which Formed in the First 500 Myr

We present the analysis of an ancient galaxy at $z=2.675$ which we dub ``Eridu.'' Simultaneously modeling the JWST/NIRSpec G140M and G235M spectra from the SMILES program and $0.4-25\ μ\mathrm{m}$ HST, JWST/NIRCam, and JWST/MIRI photometry from the the JADES+SMILES photometric catalogs shows that Eridu is massive and quiescent with stellar mass $\log(M_*/\mathrm{M_\odot})=10.96^{+0.01}_{-0.01}$ and average star formation rate $<1\ \mathrm{M_\odot\ yr^{-1}}$ over the last 100 Myr. Star formation histories inferred from various models produce disconcertingly early and fast formation within $\sim300$ Myr of the Big Bang and quenching 2 Gyr prior to observation ($z\sim10$). This stellar mass assembly implies that the progenitor of Eridu had $M_*\approx10^{11}\ \mathrm{M_\odot}$ at $z>10$, nearly two orders of magnitude more than the most massive current high redshift observations. From Eridu's spectrum we infer $\mathrm{[Mg/Fe]} =+0.65^{+0.20}_{-0.19}$, indicating its stellar population is extremely $α$-enhanced, which is consistent with the rapid formation timescale inferred from its star formation history. Eridu inhabits a massive protostructure which offers additional explanations for rapid mass assembly and quenching via environmental mechanisms, e.g. major mergers. Though its inferred formation is at odds with observations of the brightest cosmic dawn galaxies, we anticipate that future high-redshift galaxy formation models and sophisticated stellar population modeling codes will unearth how Eridu formed at the dawn of time.

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arXiv2025

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

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.

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arXiv2025

The Impact of Bars, Spirals and Bulge-Size on Gas-Phase Metallicity Gradients in MaNGA Galaxies

As galaxies evolve over time, the orbits of their constituent stars are expected to change in size and shape, moving stars away from their birth radius. Radial gas flows are also expected. Spiral arms and bars in galaxies are predicted to help drive this radial relocation, which may be possible to trace observationally via a flattening of metallicity gradients. We use data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, part of the fourth phase of the Sloan Digital Sky Surveys (SDSS-IV), to look for correlations of the steepness of gas-phase metallicity gradients with various galaxy morphological features (e.g. presence and pitch angle of spiral arms, presence of a large scale bar, bulge size). We select from MaNGA a sample of star forming galaxies for which gas phase metallicity trends can be measured, and use morphologies from Galaxy Zoo. We observe that at fixed galaxy mass (1) the presence of spiral structure correlates with steeper gas phase metallicity gradients; (2) spiral galaxies with larger bulges have both higher gas-phase metallicities and shallower gradients; (3) there is no observable difference with azimuthally averaged radial gradients between barred and unbarred spirals and (4) there is no observable difference in gradient between tight and loosely wound spirals, but looser wound spirals have lower average gas-phase metallicity values at fixed mass. We discuss the possible implications of these observational results.

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