ALMA 26 arcmin$^2$ survey of GOODS-S at one-millimeter (ASAGAO): millimeter properties of stellar mass selected galaxies

TL;DR

This study uses deep ALMA 1.2 mm observations of the GOODS-South field to investigate dust-obscured star formation in stellar mass-selected galaxies, revealing their IR properties and contribution to cosmic star formation at redshifts 2-3.

Contribution

It provides the first millimeter detection statistics for K-band selected galaxies in GOODS-S, showing their IR excess and challenging existing IRX-stellar mass relations.

Findings

24 out of 53 galaxies detected at 1.2 mm with S/N > 4.5.

ALMA-detected galaxies have higher IRX than non-detected ones.

Detected galaxies significantly contribute to the cosmic IR star formation rate density at z=2-3.

Abstract

We make use of the ASAGAO, deep 1.2 mm continuum observations of a 26 arcmin$^2$ region in the GOODS-South field obtained with ALMA, to probe dust-enshrouded star formation in $K$-band selected (i.e., stellar mass selected) galaxies, which are drawn from the ZFOURGE catalog. Based on the ASAGAO combined map, which was created by combining ASAGAO and ALMA archival data in the GOODS-South field, we find that 24 ZFOURGE sources have 1.2 mm counterparts with a signal-to-noise ratio $>$ 4.5 (1$\sigma\simeq$ 30 - 70 $\mu$Jy beam$^{-1}$ at 1.2 mm). Their median redshift is estimated to be $z_\mathrm{median}=$ 2.38 $\pm$ 0.14. They generally follow the tight relationship of the stellar mass versus star formation rate (i.e., the main sequence of star-forming galaxies). ALMA-detected ZFOURGE sources exhibit systematically larger infrared (IR) excess (IRX $\equiv L_\mathrm{IR}/L_\mathrm{UV}$) compared to ZFOURGE galaxies without ALMA detections even though they have similar redshifts, stellar masses, and star formation rates. This implies the consensus stellar-mass versus IRX relation, which is known to be tight among rest-frame-UV-selected galaxies, can not fully predict the ALMA detectability of stellar-mass-selected galaxies. We find that ALMA-detected ZFOURGE sources are the main contributors to the cosmic IR star formation rate density at $z$ = 2 - 3.