The SFR–M* Correlation Extends to Low Mass at High Redshift

Abstract

Abstract To achieve a fuller understanding of galaxy evolution, SED fitting can be used to recover quantities beyond stellar masses (M *) and star formation rates (SFRs). We use star formation histories (SFHs) reconstructed via the Dense Basis method of Iyer & Gawiser for a sample of 17,873 galaxies at 0.5 < z < 6 in the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey GOODS-S field to study the nature and evolution of the SFR–M * correlation. The reconstructed SFHs represent trajectories in SFR–M * space, enabling us to study galaxies at epochs earlier than observed by propagating them backward in time along these trajectories. We study the SFR–M * correlation at z = 1, 2, 3, 4, 5, 6 using both direct fits to galaxies observed at those epochs and SFR–M * trajectories of galaxies observed at lower redshifts. The SFR–M * correlations obtained using the two approaches are found to be consistent with each other through a K-S test. Validation tests using SFHs from semi-analytic models and cosmological hydrodynamical simulations confirm the sensitivity of the method to changes in the slope, normalization, and shape of the SFR–M * correlation. This technique allows us to further probe the low-mass regime of the correlation at high z by ∼1 dex and over an effective volume of ∼10× larger than possible with just direct fits. We find that the SFR–M * correlation is consistent with being linear down to M * ∼ 106 M ⊙ at z > 4. The evolution of the correlation is well described by , where t univ is the age of the universe in Gyr.