The SCUBA-2 Large eXtragalactic Survey (S2LXS) will map 10 square degrees of extragalactic sky at 850μm to a depth of 2 mJy per beam. The survey will be split over two deep fields covered by the the Subaru/Hyper Suprime-Cam (HSC) Survey: XMM-LSS and E-COSMOS. In the context of existing and on-going cosmology campaigns with SCUBA-2, S2LXS can be considered a wide and deep tier to complement the SCUBA-2 Cosmology Legacy Survey (Geach et al. 2017), and on-going S2-COSMOS and STUDIES Large Programmes, which survey smaller areas to higher sensitivity.
S2LXS will directly detect 370 S_850>8 mJy point sources, probing the brightest and highest redshift submillimetre galaxies. Since the confusion-limited sensitivity of Herschel/SPIRE is comparable to the S2LXS sensitivity, all S2LXS galaxies at 0 < z < 4 will be detected in the SPIRE bands, while z > 4 sources will drop out, making S2LXS an efficient high-redshift factory for efficient follow-up with sensitive interferometers. The deep HSC imaging will deliver samples of tens of thousands of z > 4 QSOs and 4 < z < 7 LBGs. S2LXS is designed to have a strong synergy with the HSC survey, with UVOIR-selected galaxy and QSO samples directly matched and cross-correlated with the wide-field 850μm imaging. This will reveal the cosmological evolution of dust enrichment, obscured star-formation, black hole growth and the link between environment and star formation out to the epoch of reionization.