First Results from the SRG/eROSITA All-Sky Survey: From Stars to Cosmology

SRG/eROSITA’s insights on the hot phase of the Circumgalactic medium in Milky-Way-sized halos: modelling and interpretation

17 Sept 2024, 15:25

15m

TUM Hörsaal/lecture hall 1 (HS 1) (Garching)

Oral X-ray emission around galaxies from CGM to WHIM

Speaker

Soumya Shreeram (Max Planck Institute for Extraterrestrial Physics)

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.