arXiv subjects

Marie Wisz

Publications and source records attributed to Marie Wisz.

2 recordsLinked to original sources

arXiv2026

The KAGG survey: KCWI Analysis of Gas around Galaxies at z~3-5

We present the KCWI Analysis of Gas around Galaxies (KAGG) survey of Ly$α$ emission around Damped Ly$α$ Absorbers (DLAs) at z~3-5 with the Keck Cosmic Web Imager (KCWI) integral-field spectrograph. The KAGG survey is characterized by the sample of 36 DLAs spanning a wide metallicity range, the wide search area for associated Ly$α$ emission (impact parameter b$~\lesssim 120~$kpc), and the high emission sensitivity, reaching Ly$α$ luminosities $\lesssim10^{42}$ erg s$^{-1}$. We identify 7 DLA Ly$α$ emitters that are likely DLA galaxy candidates due to the good match between the Ly$α$ emission and DLA redshifts. Based on a composite sample of 11 DLA Ly$α$ emitters from KAGG and MAGG (MUSE Analysis of Gas around Galaxies), we find that the impact parameters of DLA Ly$α$ emitters decrease with DLA metallicity, from b$~>50~$kpc at [M/H]~-2 to b$~<50~$kpc at [M/H]~-1. Including Ly$α$ emitters at larger velocity offsets and at larger impact parameters from the DLAs, we construct samples of 35 "Group" Ly$α$ emitters and 17 "Large-scale" Ly$α$ emitters. We find that their impact parameters and incidence rates also depend on DLA metallicity. Based on simulations of our survey and comparisons with models of galaxy formation, we conclude that higher DLA metallicities are associated with higher halo masses. The low Ly$α$ emission detection rate at low impact parameters suggests that most DLA galaxies either have low stellar masses (M$~\lesssim10^{8}M_{\odot}$) or have their Ly$α$ emission suppressed due to HI resonant scattering and/or dust absorption.

astro-ph.GA↗

arXiv2026

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

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.

astro-ph.GA↗