SCUBA-2 follow-up of Herschel-SPIRE observed Planck overdensities

We present SCUBA-2 follow-up of 61 candidate high-redshift Planck sources. Of these, 10 are confirmed strong gravitational lenses and comprise some of the brightest such submm sources on the observed sky, while 51 are candidate proto-cluster fields undergoing massive starburst events. With the accompanying Herschel-Spectral and Photometric Imaging Receiver observations and assuming an empirical dust temperature prior of 34^{+13}_{-9} K, we provide photometric redshift and far-IR luminosity estimates for 172 SCUBA-2-selected sources within these Planck overdensity fields. The redshift distribution of the sources peak between a redshift of 2 and 4, with one-third of the sources having S₅₀₀/S₃₅₀ > 1. For the majority of the sources, we find far-IR luminosities of approximately 10¹³ L_⊙, corresponding to star formation rates of around 1000 M_⊙ yr^-1. For S₈₅₀ > 8 mJy sources, we show that there is up to an order of magnitude increase in star formation rate density and an increase in uncorrected number counts of 6 for S₈₅₀ > 8 mJy when compared to typical cosmological survey fields. The sources detected with SCUBA-2 account for only approximately 5 per cent of the Planck flux at 353 GHz, and thus many more fainter sources are expected in these fields.