Event

A surprisingly tight correlation has been discovered between galaxies’ star formation rates (SFR) and stellar masses (M_*).  We show that the evolution of the normalization of the SFR-M_* correlation is driven primarily by the age of the universe.  There is an underlying correlation between galaxies’ instantaneous star formation rates and their average star formation rates since the Big Bang. The Dense Basis method of spectral energy distribution fitting allows star formation histories (SFHs) to be reconstructed, along with uncertainties, for 50,000 galaxies in the CANDELS catalogs at 0.5<z<6.  For the first time, these SFHs reveal that the SFR-M_* correlation extends to low-mass galaxies at very high redshift.  We introduce an improved estimator for burstiness and apply it to 1000 galaxies with 3D-HST H alpha detections at z~1.  Our measurements of the correlation between instantaneous, 100 Myr, and past-average star formation rates provide new constraints on the level of stochasticity in galaxy formation.