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arXiv · 1605.06433

H-ATLAS: A Candidate High Redshift Cluster/Protocluster of Star-Forming Galaxies

D. L. Clements·F. Braglia·G. Petitpas·J. Greenslade·A. Cooray·E. Valiante·G. De Zotti·B. O'Halloran·J. Holdship·B. Morris·I. Perez-Fournon D. Herranz·D. Riechers·M. Baes·M. Bremer·N. Bourne·H. Dannerbauer·A. Dariush·L. Dunne·S. Eales·J. Fritz·J. Gonzalez-Nuevo·R. Hopwood·E. Ibar·R. J. Ivison·L. L. Leeuw·S. Maddox·M. J. Michaowski M. Negrello·A. Omont·I. Oteo·S. Serjeant·I. Valtchanov·J. D. Vieira·J. Wardlow·P. van der Werf
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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 (S_870 >~7 mJy) sources at >4sigma closer than 5 arcmin to the lensed object at 850/870 microns. Ten 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 micron flux > 250 micron flux, suggesting that they lie at high redshift. Submillimeter Array (SMA) observations localise one of these companions to ~1 arcsecond, allowing unambiguous cross identification with a 3.6 and 4.5 micron Spitzer source. The optical/near-IR spectral energy distribution (SED) 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.

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D. L. Clements, F. Braglia, G. Petitpas, J. Greenslade, A. Cooray, E. Valiante, G. De Zotti, B. O'Halloran, J. Holdship, B. Morris, I. Perez-Fournon D. Herranz, D. Riechers, M. Baes, M. Bremer, N. Bourne, H. Dannerbauer, A. Dariush, L. Dunne, S. Eales, J. Fritz, J. Gonzalez-Nuevo, R. Hopwood, E. Ibar, R. J. Ivison, L. L. Leeuw, S. Maddox, M. J. Michaowski M. Negrello, A. Omont, I. Oteo, S. Serjeant, I. Valtchanov, J. D. Vieira, J. Wardlow, P. van der Werf. 2016-05-20. H-ATLAS: A Candidate High Redshift Cluster/Protocluster of Star-Forming Galaxies. https://doi.org/10.1093/mnras%2Fstw1224

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