Title: Ejective and preventive: the IllustrisTNG black hole feedback and its effects on the thermodynamics of the gas within and around galaxies
Abstract: The super-massive black holes (SMBHs) which reside at the centres of galaxies can inject vast amounts of energy into their surrounding gas and are thought to be a viable mechanism to instigate star-formation quenching in massive galaxies. By focusing on the central galaxy population of the IllustrisTNG simulation suite, we show how the three components – the SMBH, the galaxy, and the circumgalactic medium (CGM) – are all inter-connected in their evolution. In particular, the onset of the low-accretion BH feedback mode, which in the IllustrisTNG model is realised as a kinetic feedback, is shown to be simultaneously `ejective' and `preventive' - by bringing about a change in the thermodynamical properties of the gas both within the galaxy and beyond it, the star-formation is effectively shut down at stellar masses above 10^{10.5} solar masses, and any future gas accretion by radiative cooling from the CGM becomes very unlikely. Furthermore, this long-lasting quenching state can occur also in the presence of a diverse CGM which incorporates a wide range of thermodynamical states.