Timing the evolution of quiescent and star-forming local galaxies

TL;DR

This study analyzes the star formation histories of a large galaxy sample using multi-wavelength data, revealing how galaxy evolution varies with mass and current activity, and highlighting the role of environmental factors.

Contribution

It provides detailed constraints on galaxy star formation timescales and demonstrates differences in evolution between quiescent and star-forming galaxies across stellar masses.

Findings

Low-mass galaxies have more extended star formation histories.

Quiescent galaxies evolve faster than star-forming ones at the same mass.

Galaxy evolution is influenced by factors beyond stellar mass, such as mergers and environment.

Abstract

Constraining the star formation histories (SFHs) of individual galaxies is crucial to understanding the mechanisms that regulate their evolution. Here, we combine multi-wavelength (ultraviolet, optical, and infrared) measurements of a very large sample of galaxies (~230,000) at z<0.16, with physically motivated models of galaxy spectral energy distributions to extract constraints on galaxy physical parameters (such as stellar mass and star formation rate) as well as individual SFHs. In particular, we set constraints on the timescales in which galaxies form a certain percentage of their total stellar mass (namely, 10, 50 and 90%). The large statistics allows us to average such measurements over different populations of galaxies (quiescent and star-forming) and in narrow ranges of stellar mass. As in the downsizing scenario, we confirm that low-mass galaxies have more extended SFHs than high-mass galaxies. We also find that at the same observed stellar mass, galaxies that are now quiescent evolve more rapidly than galaxies that are currently still forming stars. This suggests that stellar mass is not the only driver of galaxy evolution, but plays along with other factors such as merger events and other environmental effects.