Linking galaxy structural properties and star formation activity to black hole activity with IllustrisTNG

Understand

We study the connection between active galactic nuclei (AGN) and their host galaxies through cosmic time in the large-scale cosmological IllustrisTNG simulations.

• We first compare BH properties, i.e.
• the hard X-ray BH luminosity function, AGN galaxy occupation fraction, and distribution of Eddington ratios, to available observational constraints.
• The simulations produce a population of BHs in good agreement with observations, but we note an excess of faint AGN in hard X-ray (L_x ~ 10^{43-44} erg/s), and a lower number of bright AGN (L_x>10^{44} erg/s), a conclusion that varies quantitatively but not qualitatively with BH luminosity estimation method.