Stellar and AGN feedback in isolated early-type galaxies: the role in regulating star formation and ISM properties

TL;DR

This study uses high-resolution hydrodynamical simulations to analyze how stellar winds, supernovae, and AGN feedback regulate star formation and ISM properties in isolated early-type galaxies across different masses.

Contribution

It provides a detailed comparison of feedback effects, updating AGN models and demonstrating their role in suppressing star formation in massive galaxies.

Findings

Supernova feedback maintains low star formation in low-mass ellipticals.

AGN feedback effectively offsets cooling and suppresses star formation in high-mass galaxies.

X-ray properties align with observations when feedback processes are included.

Abstract

Understanding how galaxies maintain the inefficiency of star formation with physically self-consistent models is a central problem for galaxy evolution. Although numerous theoretical models have been proposed in recent decades, the debate still exists. By means of high-resolution two-dimensional hydrodynamical simulations, we study the three feedback effects (the stellar wind heating, SNe feedback, and AGN feedback) in suppressing star formation activities on the evolution of early-type galaxies with different stellar masses. AGN feedback models are updated based on \citet{Yuan2018}. The gas sources comes exclusively from the mass losses of dying low-mass stars for most of our models. We find that SNe feedback can keep star formation at a significantly low level for low mass elliptical galaxies for a cosmological evolution time. For the high mass galaxies, AGN feedback can efficiently offset the radiative cooling and thus regulate the star formation activities. Such a suppression of star formation is extremely efficient in the inner region of the galaxies. AGB heating cannot account for this suppression for low and high mass galaxies. The X-ray temperature $T_{\rm X}$ and luminosity $L_{\rm X}$ of hot plasma can be in agreement with the observed data with the inclusion of effective feedback processes. These results thus suggest that we can use $T_{\rm X}$ and $L_{\rm X}$ to probe the role of different feedback processes. The inclusion of additional gas sources can make the mass scale between SNe and AGN feedback dominating in suppressing star formation decrease to an observationally inferred value of a few $10^{10}~M_{\odot}$.