Termination of star formation by BH feedback in equal- and unequal-mass mergers of disk and elliptical galaxies

TL;DR

This study uses galaxy merger simulations to explore how black hole feedback influences star formation termination across different galaxy types and mass ratios, revealing that feedback effects vary with merger characteristics.

Contribution

It provides new insights into the role of black hole feedback in terminating star formation during galaxy mergers with various morphologies and mass ratios.

Findings

Black hole feedback suppresses star formation more effectively in dry and mixed mergers.

Higher progenitor mass ratios reduce the impact of black hole feedback on star formation.

Star formation and black hole growth timescales increase with mass ratio.

Abstract

We present binary galaxy merger simulations of gas-rich disks (Sp-Sp), of early-type galaxies and disks (E-Sp, mixed mergers), and mergers of early-type galaxies (E-E, dry mergers) with varying mass ratios and different progenitor morphologies. The simulations include radiative cooling, star formation and black hole (BH) accretion and the associated feedback processes. We find for Sp-Sp mergers, that the peak star formation rate and BH accretion rate decrease and the growth timescales of the central black holes and newly formed stars increase with higher progenitor mass ratios. The termination of star formation by BH feedback in disk mergers is significantly less important for higher progenitor mass ratios (e.g. 3:1 and higher). In addition, the inclusion of BH feedback suppresses efficiently star formation in dry E-E mergers and mixed E-Sp mergers.