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

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.