Implications of a Temperature Dependent IMF III: Mass Growth and Quiescence

TL;DR

This paper explores how a temperature-dependent initial mass function (IMF) influences galaxy evolution, indicating that most galaxies have a top-heavier IMF and that quiescence is driven by universal mechanisms rather than environment.

Contribution

It introduces a temperature-dependent IMF parameter into photometric fitting, revealing universal quiescence mechanisms across galaxies.

Findings

Most galaxies have a top-heavier IMF than the Galactic IMF.

High-mass galaxies become quiescent first at all redshifts.

Quiescence appears driven by universal processes rather than environment.

Abstract

The stellar initial mass function (IMF) is predicted to depend upon the temperature of gas in star-forming molecular clouds. The introduction of an additional parameter, $T_{IMF}$ , into photometric template fitting, suggest most galaxies obey an IMF top-heavier than the Galactic IMF. The implications of these revised fits on mass functions, quiescence and turnoff are discussed. At all redshifts the highest mass galaxies become quiescent first with the turnoff mass decreasing towards the present. The synchronous turnoff mass across galaxies suggests quiescence is driven by universal mechanisms rather than by stochastic or environmental processes.