H-ATLAS: a candidate high redshift cluster/protocluster of star-forming galaxies

Author(s)
David L. Clements, F. Braglia, G. Petitpas, J. Greenslade, Asantha R. Cooray, Helmut Dannerbauer
Abstract

We investigate the region around the Planck-detected z = 3.26 gravitationally lensed galaxy HATLAS J114637.9-001132 (hereinafter HATLAS12-00) using both archival Herschel data from the H-ATLAS survey and using submm data obtained with both LABOCA and SCUBA2. The lensed source is found to be surrounded by a strong overdensity of both Herschel-SPIRE sources and submm sources. We detect 17 bright (S870 > ∼7 mJy) sources at >4σ closer than 5 arcmin to the lensed object at 850/870 μm. 10 of these sources have good cross-identifications with objects detected by Herschel-SPIRE which have redder colours than other sources in the field, with 350 μm flux >250 μm flux, suggesting that they lie at high redshift. Submillimeter Array (SMA) observations localise one of these companions to ∼1 arcsec, allowing unambiguous cross identification with a 3.6 and 4.5 μm Spitzer source. The optical/near-IR spectral energy distribution of this source is measured by further observations and found to be consistent with z > 2, but incompatible with lower redshifts. We conclude that this system may be a galaxy cluster/protocluster or larger scale structure that contains a number of galaxies undergoing starbursts at the same time.

Organisation(s)
Department of Astrophysics
External organisation(s)
Imperial College London, Submillimeter Array, Hilo, University of California, Irvine
Journal
Monthly Notices of the Royal Astronomical Society
Volume
461
Pages
1719 - 1733
No. of pages
15
ISSN
0035-8711
DOI
https://doi.org/10.1093/mnras/stw1224
Publication date
09-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas
Astronomy and Astrophysics, Space and Planetary Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/eed9b663-7402-453b-be1e-8f3dd3fa7507