Abstract
We present the maps, source catalogue and number counts of the largest, most complete and unbiased extragalactic submillimetre survey ever undertaken: the 850-micron SCUBA HAlf Degree Extragalactic Survey (SHADES). Using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT), SHADES mapped two separate regions of sky: the Subaru/XMM-Newton Deep Field (SXDF) and the Lockman Hole East (LH). These SCUBA maps cover 720 square arcmin with an RMS noise level of about 2 mJy and have uncovered >100 submillimetre galaxies. In order to ensure the utmost robustness of the resulting source catalogue, data reduction was independently carried out by four sub-groups drawn within the SHADES team, providing an unprecedented degree of reliability with respect to other SCUBA catalogues available from the literature. Individual source lists from the four groups were combined to produce a robust 120-object SHADES catalogue; an invaluable resource for follow-up campaigns aiming to study the properties of a complete and consistent sample of submillimetre galaxies. We present differential and integral source number counts of submillimetre galaxies and find that the differential counts are better fit with a broken power-law or a Schechter function than with a single power-law; the SHADES data alone significantly show that a break is required at several mJy, although the precise position of the break is not well constrained. We also find that an 850-micron survey complete down to 2 mJy would resolve 20-30 per cent of the Far-IR background into point sources. [abridged]
Highlights
Deep blank-field surveys conducted with the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT) have resolved as much as 50 per cent of the far-infrared (FIR) background (FIB) into discrete, high-redshift sources with flux density levels of S850 2 mJy (Smail, Ivison & Blain 1997; Barger et al 1998; Hughes et al 1998; Barger, Cowie & Sanders 1999; Blain et al 1999; Eales et al 2000; Cowie, Barger & Kneib 2002; Scott et al 2002; Borys et al 2003; Webb et al 2003)
These sources are rejected in our analysis, except in the case of LE850.10, since this source is redetected in the SCUBA Half-Degree Extragalactic Survey (SHADES) data (LOCK850.60), albeit with a lower signal-to-noise ratio (S/N) than that found in the SCUBA 8-mJy survey ( 3.4σ as compared with the previous 4.2σ detection)
Differential counts offer an advantage compared to integral source counts, since each estimate of the number of sources in a flux density bin does not depend on the counts at brighter flux densities and will be much less correlated
Summary
Deep blank-field surveys conducted with the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT) have resolved as much as 50 per cent (depending on the survey depth) of the far-infrared (FIR) background (FIB) into discrete, high-redshift sources with flux density levels of S850 2 mJy (Smail, Ivison & Blain 1997; Barger et al 1998; Hughes et al 1998; Barger, Cowie & Sanders 1999; Blain et al 1999; Eales et al 2000; Cowie, Barger & Kneib 2002; Scott et al 2002; Borys et al 2003; Webb et al 2003). Smail et al 1997; Barger, Cowie & Richards 2000; Ivison et al 2002; Smail et al 2002; Webb et al.2003; Borys et al 2004; Greve et al 2004; Wang, Cowie & Barger 2004) have suggested that SMGs are likely to be associated with an early phase in the formation of massive galaxies The intensity of their starbursts, the resulting high metallicity, along with their large dynamical masses, high gas fractions and inferred strong clustering (Blain et al 2004; Swinbank et al 2004; Greve et al 2005) are all suggestive of a close link to the formation phase of the most massive spheroids Many scientifically powerful results from SHADES will come from comparisons of the properties of sources found in the SHADES catalogue with observations at other wavelengths Some of these include radio identifications (Ivison et al, in preparation), FIR–radio photometric redshift estimates (Aretxaga et al, in preparation) and submillimetre Spitzer-based spectral energy distributions (SEDs) and photometric redshifts (Clements et al, in preparation; Eales et al, in preparation; Serjeant et al, in preparation).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
