Journal article · Preprint article
GOODS-ALMA: Optically dark ALMA galaxies shed light on a cluster in formation at z = 3.5
Nanjing University1
Aix-Marseille Université2
Durham University3
University of Sheffield4
Space Telescope Science Institute5
University of Texas at Austin6
University of Massachusetts7
National Astronomical Observatory of Japan8
Observatório Astronómico de Lisboa9
The University of Tokyo10
Texas A&M University11
Université Paris-Saclay12
Anhui Normal University13
University of Bonn14
University of Oxford15
NSF’s National Optical-Infrared Astronomy Research Laboratory16
Universidad de Concepción17
National Space Institute, Technical University of Denmark18
Astrophysics and Atmospheric Physics, National Space Institute, Technical University of Denmark19
National Observatory of Athens20
...and 10 moreThanks to its outstanding angular resolution, the Atacama Large Millimeter/submillimeter Array (ALMA) has recently unambiguously identified a population of optically dark galaxies with redshifts greater than z = 3, which play an important role in the cosmic star formation in massive galaxies. In this paper we study the properties of the six optically dark galaxies detected in the 69 arcmin2 GOODS-ALMA 1.1 mm continuum survey.
While none of them are listed in the deepest H-band based CANDELS catalog in the GOODS-South field down to H = 28.16 AB, we were able to de-blend two of them from their bright neighbor and measure an H-band flux for them. We present the spectroscopic scan follow-up of five of the six sources with ALMA band 4.
All are detected in the 2 mm continuum with signal-to-noise ratios higher than eight. One emission line is detected in AGS4 (νobs = 151.44 GHz with an S/N = 8.58) and AGS17 (νobs = 154.78 GHz with an S/N = 10.23), which we interpret in both cases as being due to the CO(6-5) line at zspecAGS4 = 3.556 and zspecAGS17 = 3.467, respectively.
These redshifts match both the probability distribution of the photometric redshifts derived from the UV to near-infrared spectral energy distributions (SEDs) and the far-infrared SEDs for typical dust temperatures of galaxies at these redshifts. We present evidence that nearly 70% (4/6 of galaxies) of the optically dark galaxies belong to the same overdensity of galaxies at z ∼3.5. overdensity.
Language: | English |
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Publisher: | EDP Sciences |
Year: | 2020 |
Pages: | A155 |
ISSN: | 14320746 and 00046361 |
Types: | Journal article and Preprint article |
DOI: | 10.1051/0004-6361/202038059 |
ORCIDs: | 0000-0003-1687-9665 and Magdis, G. |