Rise of the titans: a dusty, hyper-luminous “870 µm riser” galaxy at z~6

Oliver, Seb (2017) Rise of the titans: a dusty, hyper-luminous “870 µm riser” galaxy at z~6. Astrophysical Journal, 850 (1). ISSN 0004-637X

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We report the detection of ADFS-27, a dusty, starbursting major merger at a redshift of z=5.655, using the Atacama Large Millimeter/submillimeter Array (ALMA). ADFS-27 was selected from Herschel/SPIRE and APEX/LABOCA data as an extremely red “870 m riser” (i.e., S250m<S350m<S500m<S870m), demonstrating the utility of this technique to identify some of the highest-redshift dusty galaxies. A scan of the 3mm atmospheric window with ALMA yields detections of CO(J=54) and CO(J=65) emission, and a tentative detection of H2O(211202) emission, which provides an unambiguous redshift measurement. The strength of the CO lines implies a large molecular gas reservoir with a mass of Mgas=2.51011 (CO=0:8) (0:39=r51)M, sufficient to maintain its 2400M yr1 starburst for at least 100 Myr. The 870 m dust continuum emission is resolved into two components, 1.8 and 2.1 kpc in diameter, separated by 9.0 kpc, with comparable dust luminosities, suggesting an ongoing major merger. The infrared luminosity of LIR'2.41013 L implies that this system represents a binary hyper-luminous infrared galaxy, the most distant of its kind presently known. This also implies star formation rate surface densities of SFR=730 and 750M yr1 kpc2, consistent with a binary “maximum starburst”. The discovery of this rare system is consistent with a significantly higher space density than previously thought for the most luminous dusty starbursts within the first billion years of cosmic time, easing tensions regarding the space densities of z6 quasars and massive quiescent galaxies at z&3.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
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Depositing User: Billy Wichaidit
Date Deposited: 07 Nov 2017 11:32
Last Modified: 02 Jul 2019 13:05
URI: http://sro.sussex.ac.uk/id/eprint/71034

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Project NameSussex Project NumberFunderFunder Ref
University of Sussex Astronomy Consolidated Grant 2017-2020G2050STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/P000525/1