2017MNRAS.464L..26F

Here we utilize recent measures of galaxy total dynamical mass and X-ray gas luminosities (L_X,Gas) for a sample of 29 massive early-type galaxies from the SLUGGS survey to probe L_X, Gas_-mass scaling relations. In particular, we investigate scalings with stellar mass, dynamical mass within 5 effective radii (R_e) and total virial mass. We also compare these relations with predictions from Λ cold dark matter simulations. We find a strong linear relationship between L_X, Gas_ and galaxy dynamical mass within 5R_e, which is consistent with the recent cosmological simulations of Choi et al. that incorporate mechanical heating from AGN. We conclude that the gas surrounding massive early-type galaxies was shock-heated as it fell into collapsing dark matter haloes so that L_X, Gas_ is primarily driven by the depth of a galaxy's potential well. Heating by an AGN plays an important secondary role in determining L_X, Gas_.