DR5 Release - April 6th 2009 (August 28th 2009 for GPS and UDS)
The charts linked below show the status of the UKIDSS surveys in this
release. This fifth release, like the DR4plus release, only contains one
database, UKIDSSDR5plus, which contains all the data, i.e. includes
data from fields
that have incomplete waveband coverage as prescribed by a given survey.
The WSA DR5plus release contains views of the survey source tables that allow
users to easily target their queries at only those areas that have complete
waveband coverage. The names of the source table views are
lasYJHKsource, gpsJHKsource, gcsZYJHKsource and
dxsJKsource. These names reflect the required waveband coverage.
They appear in the schema browser under
both the table and view sections. The UDS being only one field that now has
coverage in J, H and K does not require a view.
A description of the data and how it is held in the archive is given in the
DR5 Release Summary
||No. of multiframes
||No. of objects in
|No. of sources in
||Y=20.2, J=19.6, H=18.8, K=18.2
||J=19.8, H=19.0, K=18.1
||Z=20.4, Y=20.1, J=19.6, H=18.8, K=18.2
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
Synoptic/variability tables are available for the DXS and UDS. See
the cookbook and
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.
||UDS DR5 J band
||UDS DR5 H band
||UDS DR5 K band
Issues fixed in DR5:
Particular attention should be given to any notes detailing limitations
and known issues - see below,
known issues and
- The small amount of deprecated data present in the *Source
tables in DR4plus has been removed (see
- 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).
WFAU, Institute for Astronomy,
Royal Observatory, Blackford Hill
Edinburgh, EH9 3HJ, UK