Mapping gas around massive galaxies: cross-correlation of DES Y3 galaxies and Compton-y maps from SPT and Planck

We cross-correlate positions of galaxies measured in data from the first three years of the Dark Energy Survey with Compton- 𝑦 -maps generated using data from the South Pole Telescope (SPT) and the Planck mission. We model this cross-correlation measurement together with the galaxy auto-correlation to constrain the distribution of gas in the Universe. We measure the hydrostatic mass bias or, equivalently, the mean halo bias-weighted electron pressure (cid:104) 𝑏 ℎ 𝑃 𝑒 (cid:105) , using large-scale information. We find (cid:104) 𝑏 ℎ 𝑃 𝑒 (cid:105) to be [ 0 . 16 + 0 . 03 − 0 . 04 , 0 . 28 + 0 . 04 − 0 . 05 , 0 . 45 + 0 . 06 − 0 . 10 , 0 . 54 + 0 . 08 − 0 . 07 , 0 . 61 + 0 . 08 − 0 . 06 , 0 . 63 + 0 . 07 − 0 . 08 ] meV cm − 3 at redshifts 𝑧 ∼ [ 0 . 30 , 0 . 46 , 0 . 62 , 0 . 77 , 0 . 89 , 0 . 97 ] . These values are consistent with previous work where measurements exist in the redshift range. We also constrain the mean gas profile using small-scale information, enabled by the high-resolution of the SPT data. We compare our measurements to different parametrized profiles based on the cosmo-OWLS hydrodynamical simulations. We find that our data are consistent with the simulation that assumes an AGN heating temperature of 10 8 . 5 K but are incompatible with the model that assumes an AGN heating temperature of 10 8 . 0 K. These comparisons indicate that the data prefer a higher value of electron pressure than the simulations within 𝑟 500 𝑐 of the galaxies’ halos.