Submillimetre detection of the z = 2.83 Lyman-break galaxy, Westphal-MM8, and implications for SCUBA2

Abstract

We present confusion-limited submillimetre (submm) observations with the Submillimetre Common-User Bolometer Array (SCUBA) camera on the James Clerk Maxwell Telescope of the z = 2.83 Lyman-break galaxy (LBG), Westphal-MM8, reaching an 850 μm sensitivity even greater than that achieved in the SCUBA map of the Hubble Deep Field region. The detection of MM8 (S850 μm = 1.98 ± 0.48 mJy), along with the literature submm detections of lensed LBGs, suggests that the LBG population may contribute significantly to the source counts of submm-selected galaxies in the 1-2 mJy regime. Additionally, submm-luminous LBGs are a viable progenitor population for the recently discovered evolved galaxies at z ∼ 2-2.5. These observations represent an important baseline for SCUBA2 observations which will regularly map large regions of the sky to this depth. © 2009 RAS.