The UKIRT wide-field camera

Abstract

Context. The infrared wide-field camera (WFCAM) is now in operation on the 3.8 m UK Infrared Telescope on Mauna Kea. WFCAM currently has the fastest survey speed of any infrared camera in the world, and combined with generous allocations of telescope time, will produce deep maps of the sky from Z to K band. The data from a set of public surveys, known as UKIDSS, will be initially available to astronomers in ESO member states, and later to the world. Aims. In order to maximise survey speed, the WFCAM field of view was required to be as large as possible while incorporating conventional infrared-instrument design features such as a cold re-imaged pupil stop and cryogenic optics and mechanisms. Methods. The solution adopted was to build a cryogenic Schmidt-type camera, mounted forward of the primary mirror, which illuminates a very large 0.9• diameter focal plane, containing four 2k × 2k HgCdTe Rockwell detectors. Results. Following several commissioning periods during which the camera, focal plane and telescope optical axes were successfully co-aligned, WFCAM now operates close to specifications, regularly achieving 0.7 FWHM images over the full field. Projects which already report excellent results include the detection of variability in young stellar clusters, as well as preliminary deep IR imaging of the Subaru and XMM-Newton deep field.

A large narrow-band Hα survey at z∼ 0.2: the bright end of the luminosity function, cosmic variance and clustering across cosmic time

“…Based Lawrence et al (2007). UKIDSS uses the UKIRT Wide Field Camera (WFCAM; Casali et al 2007). The photometric system is described in Hewett et al (2006), and the calibration is described in Hodgkin et al (2009).…”

THE 31 DEG2 RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

“…The approximate flux limits of the AO13 portion of the Stripe 82X survey are 2.2×10 −15 erg s −1 cm −2 , 1.3×10 −14 erg s −1 cm −2 , and 6.7×10 −15 erg s −1 cm −2 , in the soft (0.5-2 keV), hard (2-10 keV), and full (0.5-10 keV) bands. From matching the X-ray source list to available multiwavelength catalogs, including SDSS (Ahn et al 2012;Jiang et al 2014), WISE (Wright et al 2010;Mainzer et al 2011), UKIDSS (Hewett et al 2006;Casali et al 2007;Lawrence et al 2007;Warren et al 2007), VHS (McMahon et al 2013), GALEX (Morrissey et al 2007), FIRST Helfand et al 2015), and Herschel (Viero et al 2014), we identified reliable counterparts for 93% of the sample. About 29% of the X-ray sources are classified via spectroscopic redshifts.…”

“…We searched for counterparts to the XMM-Newton AO13 sources in publicly available multi-wavelength databases: SDSS, WISE (Wright et al 2010), UKIDSS (Hewett et al 2006;Casali et al 2007;Lawrence et al 2007), VHS (McMahon et al 2013), GALEX (Morrissey et al 2007), FIRST, and the Herschel Survey of Stripe 82 (HerS; Viero et al 2014). To determine whether a multi-wavelength association to an X-ray source represents the true astrophysical counterpart rather than a chance coincidence, we use the maximum likelihood estimator method (MLE; Sutherland & Saunders 1992) to match between the X-ray source lists and the ancillary catalogs.…”

“…The XMM-Newton AO13 source list was matched independently to the near-infrared (NIR) catalogs from the UKIDSS Large Area Survey (LAS; Hewett et al 2006;Casali et al 2007;Lawrence et al 2007;Warren et al 2007) and VHS (McMahon et al 2013). From both catalogs, we chose primary objects from the database 26 and eliminated objects that were consistent with noise, i.e., "mergedclass" set to zero and "pnoise" 27 >0.05.…”

“…The coadded photometry reaches 1.2-2.2 magnitudes deeper than any single SDSS scan (r∼24.6 versus r∼22.2; Annis et al 2014;Jiang et al 2014), and the full field has existing optical spectroscopy from SDSS and SDSS BOSS (Data Releases 9 and 10; Ahn et al 2012Ahn et al , 2014, 2 SLAQ (Croom et al 2009), and WiggleZ (Drinkwater et al 2010), with partial coverage from DEEP2 (Newman et al 2013), PRIMUS (Coil et al 2011), 6dF (Jones et al 2004(Jones et al , 2009, the VIMOS VLT Deep Survey (VVDS Garilli et al 2008), a deep spectroscopic survey of faint quasars from Jiang et al (2006), and a pre-BOSS pilot survey using Hectospec on MMT (Ross et al 2012). Existing multi-wavelength data in Stripe 82 include near-infrared observations from UKIDSS (Hewett et al 2006;Casali et al 2007; Lawrence et al 2007) and the VISTA Hemisphere Survey (VHS; McMahon et al 2013); farinfrared coverage from Herschel over 79 deg 2 (Viero et al 2014); ultraviolet coverage with GALEX (Morrissey et al 2007); radio observations at 1.4 GHz with Faint Images of the Radio Sky at Twenty centimeters (FIRST) (Becker et al 1995;White et al 1997;Becker et al 2012;Helfand et al 2015), with deeper VLA coverage over 80 deg 2 (Hodge et al 2011); and millimeter observations with the Atacama Cosmology Telescope (ACT; Fowler et al 2007;Swetz et al 2011). Additionally, there is Spitzer coverage in the field from the Spitzer-HETDEX Exploratory Large Area survey over 28 deg 2 (SHELA; PI: C. Papovich) and the Spitzer IRAC Equatorial Survey over 110 deg 2 (SpIES; PI: G. Richards; J.…”