The Effects of X-Ray Feedback from AGN on Host Galaxy Evolution

TL;DR

This study introduces a new AGN feedback model incorporating X-ray radiation, which significantly enhances the suppression of star formation and satellite galaxy reduction in galaxy evolution simulations.

Contribution

The paper presents a novel AGN feedback model with X-ray radiation, demonstrating improved effectiveness over traditional models in galaxy evolution simulations.

Findings

X-ray feedback doubles the suppression of star formation.

Reduces star formation in last 6 Gyr by 3 times.

Lowers final black hole mass by 30%.

Abstract

Hydrodynamic simulations of galaxies with active galactic nuclei (AGN) have typically employed feedback that is purely local: i.e., an injection of energy to the immediate neighborhood of the black hole. We perform GADGET-2 simulations of massive elliptical galaxies with an additional feedback component: an observationally calibrated X-ray radiation field which emanates from the black hole and heats gas out to large radii from the galaxy center. We find that including the heating and radiation pressure associated with this X-ray flux in our simulations enhances the effects which are commonly reported from AGN feedback. This new feedback model is twice as effective as traditional feedback at suppressing star formation, produces 3 times less star formation in the last 6 Gyr, and modestly lowers the final BH mass (30%). It is also significantly more effective than an X-ray background in reducing the number of satellite galaxies.