Star Formation Histories and Stellar Mass Growth out to z>1

TL;DR

Recent multi-wavelength surveys reveal that galaxy star formation histories are mainly mass-dependent, smooth, and gradually declining with redshift, providing a reference for galaxy evolution models, though current theories need refinement.

Contribution

This review synthesizes recent observational findings on galaxy star formation histories out to z>1, highlighting the mass dependence and smooth evolution of star formation rates.

Findings

Star formation rates decline gradually with redshift.

Galaxies of similar mass have similar star formation histories.

Current models do not fully reproduce observed star formation amplitudes and timescales.

Abstract

The deepest multi-wavelength surveys now provide measurements of star formation in galaxies out to z>1, and allow to reconstruct its history for large parts of the galaxy population. I review recent studies, which have consistently revealed a picture where galaxy star formation rates and their evolution are primarily determined by galaxy mass. Unless they undergo a quenching of their star formation, galaxies of similar masses have very similar star formation histories, which turn out to be relatively smooth: star formation rates decline with redshift in a primarily gradual manner, while typical starburst episodes have only a modest amplitude that barely evolves. I discuss how the found relations and their redshift evolution can provide an observed reference star formation history as a function of galaxy mass. The observed amplitudes and timescales of galaxy star formation are not fully reproduced by current theoretical models, and are a promising testbed to improve the assumed baryon physics. However, measurements of star formation rates in distant galaxies need to be treated with caution. Near-future data, methods and instruments will help us to improve on calibrations and sensitivities for high redshift star formation.