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 SCUBA camera on the JCMT of the z=2.83 Lyman-break galaxy (LBG), Westphal-MM8, reaching an 850um sensitivity even greater than that achieved in the SCUBA map of the Hubble Deep Field region. The detection of Westphal-MM8 (S_{850um} = 1.98+-0.48mJy), along with the literature submm detections of lensed LBGs, suggest that the LBG population may contribute significantly to the source counts of submm selected galaxies in the 1-2mJy 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.