Speaker
Description
Low-mass galaxy groups are the most common environments for galaxies in the Universe, and they provide a crucial link between cosmology and galaxy evolution. However, their hot gas and baryon content are poorly constrained by current X-ray observations due to their low surface brightness. In this talk, I will demonstrate the efficiency of X-ray spectral stacking as a method to overcome these limitations for galaxy groups coming from the major optical spectroscopic surveys, such as the SDSS, GAMA and DESI, and then observed by eROSITA All Sky Survey. I will show how this approach allows us to probe the temperature-mass relation and examine the shape of temperature and entropy profiles down to Milky Way-sized halos, where estimations from individual data are still not possible. The stacking results from eRASS1 will be compared with predictions from eROSITA mock observations based on hydro-dynamical simulations like Magneticum and IllustrisTNG. This approach not only probes the properties of intra-group medium gas in clusters on scales comparable to our own Local Group, but also expands and validates existing X-ray scaling relations to the very low-mass end. Furthermore, it traces the influence of AGN feedback on baryon distribution in groups, providing insights into their internal dynamics.
