MUSEQuBES: the column density, covering fraction, mass, and environmental dependence of cool H  <scp>i</scp> gas around low-redshift galaxies

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 $&amp;gt;2\sigma$ significance. Broad Ly $\alpha$ absorbers (BLAs) with $b&amp;gt;60$ $\rm km~s^{-1}$ 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 $D&amp;lt; R_{\rm vir}$ 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.