JCMT S2CLS Observing (Charlotte Clarke)

Lead Research Organisation: University of Sussex
Department Name: Sch of Mathematical & Physical Sciences


Charlotte Clarke will go observing on JCMT as part of S2CLS


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Geach J (2017) The SCUBA-2 Cosmology Legacy Survey: 850 µm maps, catalogues and number counts in Monthly Notices of the Royal Astronomical Society

Description We carried out observations on the JCMT telescope in Hawaii. We obtained new data contributing to deep maps of the sky, detecting distant star forming galaxies. This contributed to a catalogue of ~3000 submillimetre sources detected (=3.5s) at 850 µm over ~5 deg2 surveyed as part of the James Clerk Maxwell Telescope (JCMT) SCUBA-2 Cosmology Legacy Survey (S2CLS). This is the largest survey of its kind at 850 µm, increasing the sample size of 850 µm selected submillimetre galaxies by an order of magnitude. The wide 850 µm survey component of S2CLS covers the extragalactic fields: UKIDSS-UDS, COSMOS, Akari-NEP, Extended Groth Strip, Lockman Hole North, SSA22 and GOODS-North. The average 1s depth of S2CLS is 1.2 mJy beam-1, approaching the SCUBA-2 850 µm confusion limit, which we determine to be sc ˜ 0.8 mJy beam-1. We measure the 850 µm number counts, reducing the Poisson errors on the differential counts to approximately 4 per cent at S850 ˜ 3 mJy. With several independent fields, we investigate field-to-field variance, finding that the number counts on 0.5°-1° scales are generally within 50 per cent of the S2CLS mean for S850 > 3 mJy, with scatter consistent with the Poisson and estimated cosmic variance uncertainties, although there is a marginal (2s) density enhancement in GOODS-North. The observed counts are in reasonable agreement with recent phenomenological and semi-analytic models, although determining the shape of the faint-end slope (S850 < 3 mJy) remains a key test. The large solid angle of S2CLS allows us to measure the bright-end counts: at S850 > 10 mJy there are approximately 10 sources per square degree, and we detect the distinctive up-turn in the number counts indicative of the detection of local sources of 850 µm emission, and strongly lensed high-redshift galaxies. All calibrated maps and the catalogue are made publicly available.
Exploitation Route These data will be of great interest to a wide group of astronomers.
Sectors Education