MUSEQuBES: the column density, covering fraction, mass, and environmental dependence of cool H i gas around low-redshift galaxies
Year: 2025
Type: article
Abstract: ABSTRACT We investigate cool H i gas traced by Lyman series absorption around 256 galaxies at $z\approx 0.48$ (median stellar mass, $\log _{10}~(M_{\star }/\rm {\rm M}_{\odot })$ $= 8.7$) using 15 background quasars (median impact parameter, $D = 140$ pkpc), as part of the MUSE Quasar-fields Blind Emitters Survey (MUSEQuBES). We find that the H i column density ($N( \rm{H\,{\small I}})$) profile around isolated star-forming galaxies spanning $\approx 3$ dex in $M_{\star }$ is well described by a power law with slope $\approx -3$ when expressed as a function of normalized impact parameter $D/R_{\rm vir}$. The H i covering fraction ($\kappa$) within the virial radius for ${\rm log}_{10}(N(\rm{H\,{\small I}})/{\rm cm}^{-2})$ $= 14$ is significantly lower in high-mass passive galaxies than in isolated star-forming galaxies. The $\kappa$-profile of isolated star-forming galaxies suggests a characteristic size of the H i-rich CGM of $\approx 1.5 R_{\rm vir}$ across the stellar mass range. The mean H i mass in the outer CGM (0.3–$1~R_{\rm vir}$) increases with $M_{\star }$, ranging from $\approx 10^{5.0}$ to $10^{6.6}$ $\rm {\rm M}_{\odot }$. The b-parameters of the strongest H i components correlate and anticorrelate with specific star-formation rate (sSFR) and mass, respectively, with $>2\sigma$ significance. Broad Ly $\alpha$ absorbers (BLAs) with $b>60$ $\rm km~s^{-1}$ are predominantly associated with high-mass galaxies, likely tracing the warm-hot phase of the CGM. The velocity centroids of H i components indicate that absorbers at $D< R_{\rm vir}$ are largely consistent with being gravitationally bound to their galaxies, independent of stellar mass. Finally, leveraging $\approx 3000$ galaxies from the wide-field Magellan follow-up of six MUSEQuBES fields, we find that non-isolated galaxies exhibit an H i-rich environment extending roughly three times farther than in isolated counterparts.
Institutions: Inter-University Centre for Astronomy and Astrophysics, Leiden Observatory, University of Michigan, Centre National de la Recherche Scientifique, Centre de Recherche Astrophysique de Lyon, Leibniz Institute for Astrophysics Potsdam, University of Milano-Bicocca, University of Chicago, University of Potsdam
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
OpenAlex ID: W4416596789