Cool circumgalactic gas in galaxy clusters: connecting the DESI legacy imaging survey and SDSS DR16 Mg <scp>ii</scp> absorbers

ABSTRACT We investigate the cool gas absorption in galaxy clusters by cross-correlating Mg ii absorbers detected quasar spectra from data release 16 of Sloan Digital Sky Survey (SDSS) with identified Dark Energy Spectroscopic Instrument (DESI) survey. find significant covering fractions ($1\!-\!5\, \mathrm{per\,cent}$ within r500, depending on chosen redshift interval), ∼4–5 times higher than around random sightlines. While fraction decreases increasing mass central galaxy, total r500 is none less ∼10 for SDSS luminous red galaxies. The versus impact parameter well described a power law inner regions and an exponential function at larger distances. characteristic scale transition between these two regimes smaller large equivalent width absorbers. Cross-correlating photo−$z$ selected cluster member galaxies DESI reveals statistically connection. median projected distance nearest ∼200 kpc, compared to ∼500 kpc mocks same density profiles. do not correlation strength star formation rate closest neighbour. This suggests that clusters, as traced absorption, is: (i) associated satellite galaxies, (ii) dominated cold clouds intracluster medium, rather interstellar medium (iii) may originate part stripped satellites past.