Cool gas accretion, thermal evaporation and quenching of star formation in elliptical galaxies

TL;DR

This paper explores how hot gas accretion, thermal evaporation, and active galactic nucleus feedback contribute to quenching star formation in elliptical galaxies, explaining the observed color-magnitude diagram features.

Contribution

It proposes a comprehensive model linking gas heating, evaporation, and feedback mechanisms to the suppression of star formation in massive elliptical galaxies.

Findings

Hot interstellar medium prevents cold gas cooling.

Thermal evaporation eliminates accreted cold gas.

AGN feedback maintains hot gas conditions.

Abstract

The most evident features of colour-magnitude diagrams of galaxies are the red sequence of quiescent galaxies, extending up to the brightest elliptical galaxies, and the blue cloud of star-forming galaxies, which is truncated at a luminosity L~L*. The truncation of the blue cloud indicates that in the most massive systems star formation must be quenched. For this to happen the virial-temperature galactic gas must be kept hot and any accreted cold gas must be heated. The elimination of accreted cold gas can be due to thermal evaporation by the hot interstellar medium, which in turn is prevented from cooling by feedback from active galactic nuclei.