Far-infrared And Nebular Star-formation Rates Of Dusty Star Forming Galaxies From Herschel And 3d-hst At Z~1

TL;DR

This study analyzes dusty star-forming galaxies at redshifts 0.5 to 2.2 using multi-band SEDs and nebular emission lines from Herschel and HST data, revealing their star-formation properties and deviations from typical galaxy relations.

Contribution

It provides a comprehensive analysis of dusty star-forming galaxies combining infrared and optical data, highlighting their mass and star-formation characteristics during peak galaxy formation epoch.

Findings

Dusty star-forming galaxies deviate toward bluer colors in IRX-UV slope relation.

High-z dusty galaxies are skewed toward larger stellar masses.

These galaxies have star-formation rates consistent with the most massive main sequence galaxies.

Abstract

We present results of a multi-band Spectral Energy Distribution (SED) and nebular emission line analysis of a sample of 1147 spectroscopically identified dusty star-forming galaxies at 0.49 < z < 2.24 from Herschel/SPIRE and HST/WFC3 grism observations in the five CANDELS fields: AEGIS, GOODS-N, GOODS-S, COSMOS, and UDS. We use the spectroscopic redshifts measured from nebular lines to construct the SEDs of galaxies from the optical to the infrared using HST and Herschel photometry. We further utilize the 3D-HST grism Ha line flux measurements to measure the nebular star-formation rates after correcting for attenuation. We compare this with direct observations of the SFR measurements in the far-infrared from Herschel. Observation of the infrared excess (IRX) in this sample as a function of the UV spectral slope reveals that these DSFGs deviate toward bluer colors, thus sitting well above the expected relation for normal star-forming galaxies. The high-z dusty galaxies have a stellar mass distribution that is skewed towards larger masses, with $M_{med} = 2.6 \times 10^{10} M_{\odot}$. However this population has star-formation rates consistent with the most massive tail of the main sequence, showing that these are both the most massive and the most star-forming galaxies during the peak epoch of formation.