SXDF-UDS-CANDELS-ALMA 1.5 arcmin$^2$ deep survey

TL;DR

This deep 1.1 mm ALMA survey of a 1.5 arcmin$^2$ region in SXDF-UDS-CANDELS detects faint dusty star-forming galaxies up to redshift 10, revealing populations invisible in optical/near-infrared surveys and potentially constraining galaxy evolution at high redshift.

Contribution

First deep ALMA survey in this field demonstrating the ability to detect faint dust-obscured galaxies and identify potential high-redshift line emitters.

Findings

Detected 23 sources with S/N > 4, including 5 bright sources.

Uncovered a faint dust-obscured galaxy invisible in optical/near-infrared.

Identified a candidate [CII] or CO line emitter at z=5.955.

Abstract

We have conducted 1.1 mm ALMA observations of a contiguous $105'' \times 50''$ or 1.5 arcmin$^2$ window in the SXDF-UDS-CANDELS. We achieved a 5$\sigma$ sensitivity of 0.28 mJy, providing a flat sensus of dusty star-forming galaxies with $L_{\rm IR} \sim6\times10^{11}$ $L_\odot$ (for $T_{\rm dust}$ =40K) up to $z\sim10$ thanks to the negative K-correction at this wavelength. We detected 5 brightest sources (S/N$>$6) and 18 low-significance sources (5$>$S/N$>$4; these may contain spurious detections, though). One of the 5 brightest ALMA sources ($S_{\rm 1.1mm} = 0.84 \pm 0.09$ mJy) is extremely faint in the WFC3 and VLT/HAWK-I images, demonstrating that a contiguous ALMA imaging survey is able to uncover a faint dust-obscured population that is invisible in deep optical/near-infrared surveys. We found a possible [CII]-line emitter at $z=5.955$ or a low-$z$ CO emitting galaxy within the field, which may allow us to constrain the [CII] and/or the CO luminosity functions across the history of the universe.