Where stars form and live at high redshift: clues from the infrared

TL;DR

This study explores the relationship between dark matter halos and star formation at high redshift using infrared observations, revealing key mass scales and evolutionary trends in galaxy formation.

Contribution

It provides new insights into how star formation efficiency and related properties evolve with redshift and halo mass, using a novel IR-based approach.

Findings

Star formation rate increases with redshift, with sSFR rising by a factor of ~30 from z=0 to 2.3.

Star formation is most efficient in halos of about 5x10^11 Msun, with this characteristic mass increasing with redshift.

SFR density is dominated by halos around 7x10^11 Msun across all redshifts.

Abstract

The relation between dark matter halos and the loci of star formation at high redshift is a pressing question in contemporary cosmology. Matching the abundance of halos to the abundance of infrared (IR) galaxies, we explicit the link between dark matter halo mass (Mh), stellar mass (M*) and star-formation rate (SFR) up to a redshift of 2. Our findings are five-fold. First, we find a strong evolution of the relation between M* and SFR as a function of redshift with an increase of sSFR = SFR/M* by a factor ~30 between z=0 and z= 2.3. Second, we observe a decrease of sSFR with stellar mass. These results reproduce observed trends at redshift z>0.3. Third, we find that the star formation is most efficient in dark matter halos with Mh~5x10^11 Msun, with hints of an increase of this mass with redshift. Fourth, we find that SFR/Mh increases by a factor ~15 between z = 0 and z = 2.3. Finally we find that the SFR density is dominated by halo masses close to ~7x10^11 Msun at all redshift, with a rapid decrease at lower and higher halo masses. Despite its simplicity, our novel use of IR observations unveils some characteristic mass-scales governing star formation at high redshift.