Gravity at Work: How the Build-Up of Environments Shape Galaxy Properties

TL;DR

This paper investigates how gravitational energy from in-falling satellites heats the inter-cluster medium, significantly influencing galaxy properties and matching observed luminosity functions.

Contribution

It quantifies gravitational heating's role in galaxy environments, showing it can surpass AGN and supernova contributions in dense regions.

Findings

Gravitational heating can exceed AGN/SN energy contributions in dense environments.

Cooling is balanced by gravitational heating in hot, massive clusters.

Gravitational heating helps align galaxy luminosity models with observations.

Abstract

We present results on the heating of the inter-cluster medium (ICM) by gravitational potential energy from in-falling satellites. We calculate the available excess energy of baryons once they are stripped from their satellite and added to the ICM of the hosting environment. this excess energy is a strong function of environment and we find that it can exceed the contribution from AGNs or supernovae (SN) by up to two orders of magnitude in the densest environments/haloes. Cooling by radiative losses is in general fully compensated by gravitational heating in massive groups and clusters with hot gas temperature > 1 keV. The reason for the strong environment dependence is the continued infall of substructure onto dense environments during their formation in contrast to field-like environments. We show that gravitational heating is able to reduce the number of too luminous galaxies in models and to produce model luminosity functions in agreement with observations.