Sunyaev–Zeldovich Signals from L* Galaxies: Observations, Analytics, and Simulations

We analyze measurements of the thermal Sunyaev-Zeldovich (tSZ) effect from the circumgalactic medium (CGM) of MW-like galaxies, by comparing observations to our phenomenologically driven analytical models and the TNG100 simulation. An observation by Bregman et al. 2022 Compton-y profile implies steep electron pressure slopes. Considering the possibility of a hydrostatic equilibrium, we find that the B+22 galaxies favor an isentropic equation of state over an isothermal one. The B+22 results are consistent with a similar work by Das et al. 2023, and with recent (0.5-2 keV) CGM X-ray observations by Zhang et al. 2024 of Milky Way mass systems. TNG100 underpredicts the tSZ parameters by relatively 0.5 dex for L* galaxies, suggesting that the feedback strengths and CGM gas losses are overestimated in the simulated halos at these mass scales.