A submillimetre-bright z ~ 3 overdensity behind a z ~ 1 supercluster revealed by SCUBA-2 and Herschel

A. G. Noble*, E. Geach, A. J. van Engelen, T. M.A. Webb, K. E.K. Coppin, A. Delahaye, D. G. Gilbank, M. D. Gladders, R. J. Ivison, Y. Omori, H. K.C. Yee

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We present a wide-field (30 arcmin diameter) 850 μmSubmillimetre Common-User Bolometer Array-2 map of the spectacular three-component merging supercluster, RCS 231953+00, at z = 0.9. The brightest submillimetre galaxy (SMG) in the field (S850 ≈ 12 mJy) is within 30 arcsec of one of the cluster cores (RCS 2319-C), and is likely to be a more distant, lensed galaxy. Interestingly, the wider field around RCS 2319-C reveals a local overdensity of SMGs, exceeding the average source density by a factor of 4.5, with a <1 per cent chance of being found in a random field. Utilizing Herschel observations from the Spectral and Photometric Imaging Receiver, we find that three of these SMGs have similar submillimetre colours. We fit their observed 250-850 μm spectral energy distributions to estimate their redshift, yielding 2.5<z<3.5, and calculate prodigious star formation rates ranging from 500 to 2500M⊙ yr-1. We speculate that these galaxies are either lensed SMGs, or signpost a physical structure at z ≈ 3: a 'protocluster' inhabited by young galaxies in a rapid phase of growth, destined to form the core of a massive galaxy cluster by z = 0.

Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
Publication statusPublished - 4 Sept 2013

Keywords / Materials (for Non-textual outputs)

  • Galaxies: clusters: individual: RCS 231946+0030.6
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: high-redshift
  • Submillimetre: galaxies


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