Serendipitous discovery of an "ALMA-only" galaxy at 5 < z < 6 in an ALMA 3-mm survey
Abstract
We discuss the serendipitous discovery of a dusty high-redshift galaxy in a small (8 arcmin2) ALMA 3-mm survey Williams et al. (<xref rid="r29" ref-type="bibr">2019</xref>). The galaxy was previously unknown and is absent from existing multi-wavelength catalogs ("ALMA-only"). Using the ALMA position as prior, we perform forced deblended photometry to constrain its spectral energy distribution. The spectral energy distribution is well described by a massive (M* = 1010.8 M⊙) and highly obscured (AV ∼ 4) galaxy at redshift z = 5.5 ± 1.1 with star formation rate ∼ 300 M⊙yr-1. Our small survey area implies an uncertain but large contribution to the cosmic star formation rate density, similar to the contribution from all ultraviolet-selected galaxies combined at this redshift. This galaxy likely traces an abundant population of massive galaxies absent from current samples of infrared-selected or sub-millimeter galaxies, but with larger space densities, higher duty cycles, and significant contribution to the cosmic star-formation rate and stellar mass densities.
- Publication:
-
Uncovering Early Galaxy Evolution in the ALMA and JWST Era
- Pub Date:
- 2020
- DOI:
- 10.1017/S1743921320000605
- Bibcode:
- 2020IAUS..352..194W
- Keywords:
-
- galaxies: formation;
- galaxies: evolution;
- galaxies: high-redshift