Studying the distribution and properties of hot gas around galaxies (hot CGM) is helpful to understand the galaxy evolution and explain the bi-modality of the galaxy population, but its observation is challenging. In my talk, I will introduce how eROSITA X-ray all-sky survey allow us to study the hot CGM with a large sample of galaxies and provide more general relationship between CGM and galaxy properties, i.e. stellar mass. Using the DESI Legacy Imaging Surveys DR9 (LS DR9), we build an ‘isolated’ galaxy sample containing about 220k galaxies locate at less dense environment, with z<0.4 and 9.5<logM_*<12. We stack the galaxies and detect extended hot CGM around M31-like galaxies. We find the X-ray surface brightness profiles of central and satellite galaxies are different. We give the relationship between hot CGM X-ray luminosity and the stellar mass down to logM_*=10.5, the relation between hot CGM X-ray luminosity and halo mass down to logM_halo=12. We find same relationships in star-forming and quiescent galaxies.
Host: Junjie Mao
