X-raying CAMELS: Constraining Feedback Physics in Hot Halo Gas with CAMELS and eRASS

          @misc{ pirsa_PIRSA:25070012,
            doi = {10.48660/25070012},
            url = {https://pirsa.org/25070012},
            author = {Lau, Erwin},
            keywords = {Cosmology},
            language = {en},
            title = {X-raying CAMELS: Constraining Feedback Physics in Hot Halo Gas with CAMELS and eRASS},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {jul},
            note = {PIRSA:25070012 see, \url{https://pirsa.org}}
          }
          

Abstract

The circumgalactic medium (CGM) around massive galaxies plays a crucial role in regulating star formation and feedback. Using the CAMELS cosmological simulation suites, we develop emulators for the X-ray surface brightness profile and the X-ray luminosity–stellar mass scaling relation to investigate how stellar and AGN feedback shape the X-ray properties of the hot CGM. Our analysis shows that stellar feedback more significantly impacts the X-ray properties than AGN feedback within the parameters studied. Comparing the emulators to recent eROSITA All-Sky Survey observations, we found stronger feedback is needed than those currently implemented in the IllustrisTNG, SIMBA, and Astrid simulations, in order to match observed CGM properties. However, adopting these enhanced feedback parameters leads to deviations in the observed stellar-mass-halo-mass relations below the group mass scale. This tension suggests possible unaccounted systematics in X-ray CGM observations or inadequacies in the feedback models of cosmological simulations. Finally, I will also highlight upcoming X-ray constraints of feedback in the group and cluster scales with new CAMELS simulations and compare with those obtained at the CGM scale.