UKIRT Infrared Deep Sky Survey (UKIDSS)

Third Data Release (DR3)

Thursday 6 December 2007

UKIDSS DR3 was released today, Thurs 6 December. UKIDSS is a set of 5 large near-infrared surveys that began in May 2005, and will take 7 years to complete. DR3 is the third large release of survey-quality data from UKIDSS. DR3 will actually occur in two parts. The first part includes new data for the LAS, GCS, DXS, and UDS, taken over Nov 2006 to May 2007. It is planned to release the GPS DR3 data later in December, or in early January.

Please note that the archive will unfortunately not be available this Saturday Dec 8, for scheduled downtime (because of planned electrical works at the Royal Observatory Edinburgh).

The table below sumarises the DR3 sky coverage and K-band depth (for regions with the full filter complement) for each of the five surveys. DR3 also contains a comparable quantity of data where the filter complement is incomplete.

The main characteristics of DR3, in comparison with DR2 are as follows. The LAS and GCS coverage are a factor of three larger. The DXS has increased in area only incrementally (from 6 to 7 sq degs), while the average depth has improved slightly. For the UDS the main improvement has been the inclusion of H-band data, while the increase in depth in the J and K filters is modest.

There has been a significant change to the calibration of Y filter data (i.e. LAS and GCS). The zero point of all Y data has been adjusted by +0.08 mag i.e. for the same object Y(DR3)-Y(DR2)=0.08. This change brings the Y band onto the Vega system described in Hewett et al. (2006, MNRAS, 367, 454).

Access to DR3 is through the WFCAM Science Archive. Please also note carefully the release notes on the WSA pages.

You need an account to access the data. If you are not yet registered for access, read the text on the UKIDSS Archive page and follow the instructions.

A paper describing DR3 is in preparation, but a draft is not yet available. Technical information on the UKIDSS surveys is contained in the following publications

• Casali et al. (2007) 'The UKIRT wide-field camera', A&A, 467, 777
• Dye et al. (2006) 'The UKIDSS Early Data Release', MNRAS, 372, 1227
• Hambly et al. (2007) 'The WFCAM science archive', MNRAS in press, arXiv:astro-ph/0711.3593
• Hewett et al. (2006) 'The UKIDSS ZYJHK photometric system', MNRAS, 367, 454
• Lawrence et al. (2007) 'The UKIRT Infrared Deep Sky Survey', MNRAS, 379, 1599
• Lucas et al.(2007) 'The UKIDSS Galactic Plane Survey', arXiv:astro-ph/0712.0100
• Warren et al. (2007) 'The UKIDSS First Data Release', MNRAS, 375, 213
• Warren et al. (2007) 'The UKIDSS Second Data Release', arXiv:astro-ph/0703037

In broad outline, the contents of DR3 are as follows, labeled by survey:

Andy Lawrence (UKIDSS PI), Steve Warren (UKIDSS Survey Scientist), on behalf of the UKIDSS Consortium