The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations

Bakx, Tom J.L.C. and Eales, S.A. and Negrello, M. and Smith, M.W.L. and Valiante, E. and Holland, W.S. and Baes, M. and Bourne, N. and Clements, D.L. and Dannerbauer, H. and De Zotti, G. and Dunne, L. and Dye, S. and Furlanetto, C. and Ivison, R.J. and Maddox, S. and Marchetti, L. and Michałowski, M.J. and Omont, A. and Oteo, I. and Wardlow, J.L. and van der Werf, P. and Yang, C. (2018) The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations. Monthly Notices of the Royal Astronomical Society, 473 (2). pp. 1751-1773. ISSN 0035-8711

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We present the Herschel Bright Sources (HerBS) sample, a sample of bright, high-redshift Herschel sources detected in the 616.4 deg2 Herschel Astrophysical Terahertz Large Area Survey. The HerBS sample contains 209 galaxies, selected with a 500 μm flux density greater than 80 mJy and an estimated redshift greater than 2. The sample consists of a combination of hyperluminous infrared galaxies and lensed ultraluminous infrared galaxies during the epoch of peak cosmic star formation. In this paper, we present Submillimetre Common- User Bolometer Array 2 (SCUBA-2) observations at 850 μm of 189 galaxies of the HerBS sample, 152 of these sources were detected. We fit a spectral template to the Herschel-Spectral and Photometric Imaging Receiver (SPIRE) and 850 μm SCUBA-2 flux densities of 22 sources with spectroscopically determined redshifts, using a two-component modified blackbody spectrum as a template.We find a cold- and hot-dust temperature of 21.29+1.35−1.66 and 45.80+2.88−3.48 K, a cold-to-hot dust mass ratio of 26.62+5.61−6.74 and a β of 1.83+0.14−0.28. The poor quality of the fit suggests that the sample of galaxies is too diverse to be explained by our simple model. Comparison of our sample to a galaxy evolution model indicates that the fraction of lenses are high. Out of the 152 SCUBA-2 detected galaxies, the model predicts 128.4 ± 2.1 of those galaxies to be lensed (84.5 per cent). The SPIRE 500 μm flux suggests that out of all 209 HerBS sources, we expect 158.1 ± 1.7 lensed sources, giving a total lensing fraction of76 per cent.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Keywords: gravitational lensing: strong – galaxies: high-redshift – submillimetre: galaxies
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1093/mnras/stx2267
Depositing User: Eprints, Support
Date Deposited: 03 Jan 2018 10:59
Last Modified: 04 Jan 2018 12:20

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