2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/172096The UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) has the necessary combination of filters (Y, J, H and K), depth (Y <~ 20.2) and area coverage (~4000 deg^2) to detect several redshift z >~ 6.4 quasars. The Third Data Release (DR3) included ~1000 deg^2 of LAS observations which have so far yielded two previously known z ~= 6 quasars and two new discoveries: ULAS J0203+0012, at z = 5.72; and ULAS J1319+0950, at z = 6.13.to appear in Proceedings of the XXth Moriond Meeting: Cosmology, J. Tran Thanh Van et al., eds.; 4 pages, 2 figuresAstrophysicstext