The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation

Understand

Understanding the physical processes that drive star formation is a key challenge for galaxy formation models.

• In this article we study the tight correlation between the star formation rate (SFR) and stellar mass of galaxies at a given redshift, how halo growth influences star formation, and star formation histories of individual galaxies.
• We study these topics using Illustris, a state-of-the-art cosmological hydrodynamical simulation of galaxy formation.
• Illustris reproduces the observed relation (the star formation main sequence; SFMS) between SFR and stellar mass at redshifts z=0 and z=4, but at intermediate redshifts of z~2, the simulated SFMS has a significantly lower normalisation than reported by observations.