Speaker
Description
The CGM's hot phase probes the modern puzzles of galaxy formation and evolution as galaxies' feedback processes imprint their signatures in its volume-filling hot gas distribution. This talk presents state-of-art observed hot gas profiles of the CGM in Milky-Way-sized halos, obtained with the depth of eRASS:4 and the large area optical coverage of the LSS DR10 galaxy survey. Together with other observational results detecting hot CGM radial profiles with eROSITA (Zhang et al. 2024a,b), we present a new empirical model for interpreting the soft X-ray observations of the CGM's hot phase ($>10^6$ K). The model considers emission in the X-ray wavelength range from the hot gas surrounding galaxies, the population of X-ray binaries in galaxies and their AGN. Furthermore, I will present the importance of accounting for all observed projection effects, such as (1) large-scale structure along the line of sight, (2) contamination by mis-centring on satellite galaxies, and (3) contribution of point sources within the two-halo terms. This paves the way for enhancing the interpretability of emission studies of the hot CGM with current and future X-ray observations. Given the observational benchmarks with the modelling technique presented here, we also show how future state-of-the-art hydro-dynamical simulations could use our results to calibrate gas properties in the Milky Way mass halo regime.
