Home | Overview | Browser | Access | Login | Cookbook | nonSurvey

DR5 Release - April 6th 2009 (August 28th 2009 for GPS and UDS)

A description of the data and how it is held in the archive is given in the data overview.

DR5 Release Summary

New in DR5:

• The GPS now has second-epoch observations in the K filter in some fields. The detections from both epochs are merged into the gpsSource table using attributes K_1 and K_2. The frame set association algorithm for the GPS has been modified so that the epoch difference between K_1 and the J and H frames is minimised in order that the H-K_1 colours are as contemporaneous as possible and the affects of any variability on those colours is minimised. Please note that for DR5, because those areas covered by 2 K epochs were originally covered by K only, and then revisited at JHK for colours and second epoch K, this results in K_1 describing the most recent observations, closest in time to the corresponding J & H filter observations, and where there are corresponding original K-only filter observations, K_2 attributes map these earlier observations.
• Some GPS observations from earlier semesters have been reprocessed in DR5 to filter out background nebulosity and so improve the extracted catalogues. These new reprocessed frames have a new frame type, "filt", in the database Multiframe table column, frameType. The original unfiltered images remain in the DR5 database, but are marked as deprecated with the 111 flag, so their detections are no longer included in the gpsDetection of gpsSource tables. The original unfiltered images are the true images of the sky. However, the filtered catalogues have more complete and reliable photometry in fields with nebulosity. The interface returns links where appropriate to allow users to readily view the original image. MultiGetImage and ColourImage used the original images not the filtered ones. The original images can also be referenced from the corresponding filtered images via the new Multiframe column unfilteredID that links to the multiframeID of the original unfiltered image.
• Synoptic/variability tables are available for the DXS and UDS. See the cookbook and schema browser. There is slightly more noise in the UDS multi-epoch measurements because the recalibration used a wide aperture without an aperture correction rather than a small aperture with aperture corrections, because aperture corrections had not been calculated in the past for UDS mosaics and the information is not currently propagated in the database.
• A new UDS mosaic has been prepared and included in the DR5 release. All the UDS K-band intermediate stack data have been reprocessed to improve the sky subtraction. The K-band mosaic is derived from these data (as are the intermediate stack catalogues that are used in the synoptic tables).
• Unlike in previous releases, we have derived seeing, average stellar ellipticity parameters and aperture corrections for the UDS mosaics. We have not applied the aperture corrections to the UDS aperture magnitudes, but they are in the headers as WAPCOR1, WAPCOR2 ... WAPCOR7 and are tabulated below.

Mosaic UDS DR5 J band UDS DR5 H band UDS DR5 K band WAPCOR1 0.9962 mag 0.8114 mag 0.6775 mag WAPCOR2 0.5572 mag 0.4481 mag 0.3627 mag WAPCOR3 0.2618 mag 0.2257 mag 0.1854 mag WAPCOR4 0.1083 mag 0.1051 mag 0.0922 mag WAPCOR5 0.0458 mag 0.0437 mag 0.0410 mag WAPCOR6 0.0170 mag 0.0157 mag 0.0144 mag WAPCOR7 0.0038 mag 0.0036 mag 0.0033 mag

Issues fixed in DR5:

• The small amount of deprecated data present in the *Source tables in DR4plus has been removed (see known issues).
• It was found that new zeropoints calculated for DXS intermediate stacks on comparison with deep stacks were not updated in MultiframeDetector, although the detection tables were updated correctly. This error has been fixed and MultiframeDetector is consistent with the dxsDetection (see known issues).