The SCUBA-2 Cluster Snapshot Survey – I. Catalogue of lensed galaxies and submillimetre-bright central galaxies

The SCUBA-2 Cluster Snapshot Survey (S2CSS) observed 202 rich clusters of galaxies at 850 μm in relatively poor submillimetre observing conditions (⁠τ225GHz>0.1⁠) with the aim of identifying rare examples of bright (tens of mJy) gravitationally lensed submillimetre galaxies. The S2CSS covered over 0.33 deg2 to an average depth of σ850≈12 mJy beam−1. Here we present a sample of 97 bright 850-μm point sources selected from the S2CSS that are potentially gravitationally lensed, and eight sources for which the strong submillimetre emission is co-located with the central brightest cluster galaxy (BCG). We construct far-infrared spectral energy distributions for those sources with Herschel SPIRE coverage and use these distributions to estimate the redshifts and luminosities of the sources. The bright submillimetre flux density of our sources makes them excellent targets for detailed follow-up work that will allow the detection of spectral features in the submillimetre/millimetre that would otherwise be too faint to detect. Through a stacking analysis, we also investigate the average submillimetre/radio properties of BCGs, determining the average 850-μm flux of BCGs as a function of radio luminosity