Bridging between the Integrated and Resolved Main Sequence of Star Formation

June 2020 • 2020ApJ...896L..17H

Authors • Hemmati, Shoubaneh • Mobasher, Bahram • Nayyeri, Hooshang • Shahidi, Abtin • Capak, Peter • Darvish, Behnam • Chartab, Nima • Jafariyazani, Marziye • Sattari, Zahra

Abstract • The position of galaxies on the stellar mass, star formation rate (SFR) plane with respect to the star-forming main sequence at each redshift is a convenient way to infer where the galaxy is in its evolution compared to the rest of the population. We use Hubble Space Telescope high-resolution images in the GOODS-S field from the the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) and fit multiwavelength lights in resolution elements of galaxies with stellar population synthesis models. We then construct resolved kpc-scale stellar mass, SFR surface density curves for galaxies at z ∼ 1. Fitting these resolved main sequence curves with Schechter functions, we parameterize and explain the multiwavelength structure of galaxies with three variables: φ*, α, and M*. For quenched galaxies below the main sequence, we find an average high-mass slope (α) of the resolved main sequence curves to be ∼-0.4. The scatter of this slope is higher among the lower mass star-forming galaxies and those above the main sequence compared to quenched galaxies, due to lack of an evolved bulge. Our findings agree well with an inside-out quenching of star formation. We find that the knee of the Schechter fits (M*) for galaxies below the main sequence occurs at lower stellar mass surface densities compared to star-forming galaxies, which hints at how far quenching has proceeded outward.


IPAC Authors


Shoubaneh Hemmati

Assistant Scientist