Dr. Sanskriti Das

Despite being challenging to detect, the =106 K hot circumgalactic medium (CGM) is a treasure trove of galaxy evolution. By probing the hot CGM of the Milky Way (MW) using X-ray absorption lines, we have discovered a super-virial 107 K phase coexisting with the well-known virialized 106 K phase, featuring non-solar abundance ratios of light elements, a-enhancement, and non-thermal line broadening. I have also detected this super-virial phase of MW CGM in X-ray emission analyses. Detection of these surprising properties of the CGM along multiple directions in the sky suggests a strong connection between the hot CGM and past Galactic outflow(s). Observations of MW-like galaxies complement our observations of the Milky Way. We have discovered the hot CGM emission of an MW-mass galaxy NGC 3221 that is extended (=150 kpc) and is massive enough to account for its missing baryons. The CGM is not isothermal, with the CGM within 100 kpc of NGC 3221 being super-virial, and fainter along the minor axis than the global average. These results, at par with our findings in the Milky Way, compel us to rethink the impact of galactic feedback on the hot CGM of star-forming galaxies without an active nucleus.