The Differential Assembly of the Centers and Outskirts of Main Sequence Galaxies at z~2.3

Abstract

UMass Amherst Journal Club - Second Year Talk

Date
Nov 1, 2021 4:00 PM — 5:00 PM
Event
UMass Amherst Journal Club
Location
UMass Amherst, Department of Astronomy

We present a sample of 60 z~2.3 main sequence, star-forming galaxies from the MOSDEF survey in GOODS-N with SED fits to decomposed central and outer components. These galaxies are decomposed into two components using apertures selected from observed z-H colors. SED fitting is done with Prospector on HST ACS and WFC3, Spitzer/IRAC, and ground-based photometry, with additional constraints from MOSDEF metallicities and spectroscopic redshifts. Because we decompose the galaxies into only two components, we are able to iteratively determine the IRAC and ground-based photometry of each component while conserving total flux. Our final sample contains stellar population parameters and SFHs for the center, outskirts, and integrated light of each galaxy. SFHs indicate that the majority of galaxies with logM<10.5 form their central region in bursts of star formation. Moreover, the galaxies with the sharpest peaks in SFR span a wide range in size and central density. This implies that the formation of these central parts likely occurred via an increase in the accretion rate of star forming clumps, rather than the collapse of a gaseous disk. Further analysis of the uncertainties from the decomposition and choice of priors is necessary to determine if these results are robust.

Sam E. Cutler
Sam E. Cutler
Astronomy PhD Student