The JCMT Legacy Release: SCUBA-2 850 μm Coadds and Catalogs

Abstract

We present the James Clerk Maxwell Telescope (JCMT) 850 μm Legacy Release, containing uniformly reduced, coadded tiles, and catalogs of detected emission, for the 850 μm data from all Submillimetre Common User Bolometer Array 2 (SCUBA-2) observations taken between 2011 February 2 and 2020 August 1. This release provides the fastest and easiest way to identify uniformly determined 850 μm detections and calibrated fluxes for any position observed by the JCMT. The coadded observations include 11,722 hr of observing time and cover 1516 square degrees of the sky, with detections of contiguous areas of emission at better than 5σ covering 2.46 square degrees of area. Within these regions 21,059 individual local maxima were detected. Fifteen tiles contain regions with a noise level better than 0.0025 mJy arcsec−2. The data are gridded onto HEALPix tiles of ≈1° a side, using the HEALPix projection with pixels of size ≈3.″22. The coadds have been calibrated into units of mJy arcsec−2 using the standard date-varying SCUBA-2 flux-conversion factor (FCF) from Mairs et al. (2021). We then examined the accuracy of this calibration for our data set by calculating self-derived FCF values for our two most-used standard sources, finding a result within the expected errors but with a larger standard deviation of 9%. The coadds and catalogs can be searched and retrieved via the Canadian Astronomy Data Centre (project code: JCMT-LR). Combined catalogs of all detected regions and of all local maxima can be downloaded from the Canadian Advanced Network for Astronomy Research Data Publication Service (doi:10.11570/23.0013), along with masks showing the full area observed in this release and the full area of detected emission.