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

Bakx, Tom J. L. C.; Bakx, Tom J.L.C.; Eales, S. A.; Negrello, M.; Smith, M. W. L.; Valiante, E.; Holland, W. S.; Baes, M.; Bourne, N.; Clements, D. L.; Dannerbauer, H.; De Zotti, G.; Dunne, L.; Dye, S.; Furlanetto, C.; Ivison, R. J.; Maddox, S.; Marchetti, L.; Micha?owski, M. J.; Omont, A.; Oteo, I.; Wardlow, J. L.; van der Werf, P.; Yang, C.

Abstract

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.

Citation

Bakx, T. J. L. C., Bakx, T. J., Eales, S. A., Negrello, M., Smith, M. W. L., Valiante, E., …Yang, C. (2018). The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations. Monthly Notices of the Royal Astronomical Society, 473(2), 1751-1773. https://doi.org/10.1093/mnras/stx2267

• Journal Article Type: Article
• Acceptance Date: Aug 29, 2017
• Online Publication Date: Sep 4, 2017
• Publication Date: Jan 11, 2018
• Deposit Date: Jan 3, 2018
• Publicly Available Date: Jan 3, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 473
• Issue: 2
• Pages: 1751-1773
• DOI: https://doi.org/10.1093/mnras/stx2267
• Keywords: gravitational lensing: strong – galaxies: high-redshift – submillimetre: galaxies
• Public URL: https://nottingham-repository.worktribe.com/output/903834
• Publisher URL: https://academic.oup.com/mnras/article/473/2/1751/4103565
• 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.