The SCUBA Half-Degree Extragalactic Survey -- I. Survey motivation, design and data processing

Abstract

The Submillimetre Common-User Bolometer Array (SCUBA) Half-Degree Extragalactic Survey (SHADES) is a major new blank-field extragalactic submillimetre (submm) survey currently underway at the James Clerk Maxwell Telescope (JCMT). Ultimately, SHADES aims to cover half a square degree at 450 and 850 μm to a 4σ depth of ≃ 8 mJy at 850 μm. Two fields are being observed, the Subaru/XMM–Newton Deep Field (SXDF) (02h18m− 05°) and the Lockman Hole East (10h52m+ 57°). The survey has three main aims: (i) to investigate the population of high-redshift submm galaxies and the cosmic history of massive dust-enshrouded star formation activity; (ii) to investigate the clustering properties of submm-selected galaxies in order to determine whether these objects could be progenitors of present-day massive ellipticals; and (iii) to investigate the fraction of submm-selected sources that harbour active galactic nuclei. To achieve these aims requires that the submm data be combined with co-spatial information spanning the radio-to-X-ray frequency range. Accordingly, SHADES has been designed to benefit from ultra-deep radio imaging obtained with the Very Large Array (VLA), deep mid-infrared observations from the Spitzer Space Telescope, submm mapping by the Balloon-borne Large Aperture Submillimetre Telescope (BLAST), deep near-infrared imaging with the United Kingdom Infrared Telescope, deep optical imaging with the Subaru Telescope and deep X-ray observations with the XMM–Newton observatory. It is expected that the resulting extensive multiwavelength data set will provide complete photometric redshift information accurate to δz~^ 3σ at 850 μm. Although uncorrected for Eddington bias, this source density is more than sufficient for providing enough sources to answer the science goals of SHADES, once half a square degree is observed. A refined reanalysis of the original 8-mJy survey Lockman hole data was carried out in order to evaluate the new data-reduction pipeline. Of the 17 most secure sources in the original sample, 12 have been reconfirmed, including 10 of the 11 for which radio identifications were previously secured.