The IRAM/GISMO 2 mm Survey in the COSMOS Field
Abstract
We present deep continuum observations at a wavelength of 2 mm centered on the COSMOS field using the Goddard IRAM Superconducting Millimeter Observer (GISMO) at the IRAM 30 m telescope. These data constitute the widest deep 2 mm survey to date, reaching a uniform σ ∼ 0.23 mJy beam-1 sensitivity over ∼250 arcmin2 at ∼24″ resolution. We detect four sources at high significance (S/N ≥ 4.4) with an expected number of false detections of 0.09 sources and five sources at 4.4 > S/N ≥ 3.7 with an expected number of false detections of 1.65 sources. Combined with deep GISMO observations in GOODS-N, we constrain the 2 mm number counts over one decade in flux density. These measurements agree with most galaxy evolution models tested here, except those with a large population of dusty star-forming galaxies at z > 7. Five GISMO sources have counterparts in (sub)millimeter catalogs available in COSMOS. Their redshifts suggest that all but one lie above z ∼ 3. These four high-redshift (z > 3) galaxies have \tilde{z} = 3.9, SFRs ∼ 400-1200 M ⊙ yr-1, and M dust ∼ 109.5 M ⊙. They provide a relatively complete selection (∼66%) of the most luminous (L IR > 1012.6 L ⊙) and highest-redshift (z > 3) galaxies detected within our survey area by AzTEC at 1.1 mm. We thus conclude that 2 mm surveys favor the selection of massive, vigorously star-forming, high-redshift galaxies. This is corroborated by GISMO-C4, a source with a low false-detection probability (∼6.2%), for which the absence of a (sub)millimeter counterpart supports a high-redshift origin (z ≳ 3).
Based on observations with the IRAM 30 m telescope.- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2019
- DOI:
- 10.3847/1538-4357/ab1912
- arXiv:
- arXiv:1904.10006
- Bibcode:
- 2019ApJ...877...45M
- Keywords:
-
- galaxies: evolution;
- galaxies: formation;
- galaxies: high-redshift;
- galaxies: luminosity function;
- mass function;
- galaxies: photometry;
- galaxies: starburst;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 27 pages, 14 figures, accepted for publication in ApJ