Description of the dataset
The current release comprises JHKs imaging on the D1, D2, D3 and D4 CFHTLS legacy survey fields processed using the TERAPIX/WIRCam pipeline developed by P. Hudelot. A detailed description of the data processing steps involved will appear in a forthcoming paper (Bielby et al., in preparation). This release concerns all images taken in the D1, D2, D3 and D4 fields.
All images are the product of observations taken with the WIRCam instrument on the CFHT, except for the WIRDS-D2 J-band image, which is produced from data taken on the WFCAM instrument on UKIRT. The D2 data has been obtained in collaboration with COSMOS.
All observations for the WIRDS project have now been completed and this data release comprises the final data sample.
The WIRDS-T0002 stacks are first being made available to all registered CFHTLS users. From the 21st October 2010 all WIRDS-T0002 data will become public world-wide.
Data access point
All images and catalogues are distributed by the CADC at this location.
Data summary release table
The following table describes what data is being made available in this release. For a full explanation of terms used please refer to the explanatory table .
|Field||Filter||Seeing||50% Point-source completeness||Exposure time (s)||Area (deg^2)||Number counts|
|D1||J (qFITS)||0.80''||24.94 (plot)||12105||0.5984||J-band counts|
|D1||H (qFITS)||0.68''||24.71 (plot)||13600||0.5984||H-band counts|
|D1||Ks (qFITS)||0.73''||24.73 (plot)||15700||0.5984||Ks-band counts|
|D2||J (qFITS)||1.09''||24.25 (plot)||0.80||J-band counts|
|D2||H (qFITS)||0.86''||24.54 (plot)||0.80||H-band counts|
|D2||Ks (qFITS)||0.80''||24.32 (plot)||0.80||Ks-band counts|
|D3||J (qFITS)||0.81''||25.00 (plot)||16700||0.4165||J-band counts|
|D3||H (qFITS)||0.72''||24.86 (plot)||15800||0.4165||H-band counts|
|D3||Ks (qFITS)||0.74''||24.69 (plot)||17500||0.4165||Ks-band counts|
|D4||J (qFITS)||0.73''||25.10 (plot)||17500||0.4099||J-band counts|
|D4||H (qFITS)||0.69''||24.62 (plot)||14900||0.4099||H-band counts|
|D4||Ks (qFITS)||0.71''||24.62 (plot)||14200||0.4099||Ks-band counts|
Description of the stacked images
All D1, D3 and D4 images have been stacked using a modified SWarp to make average sigma-clipped stacks. The D2 images have all been produced using SWarp with a median combination.
All images have a the same tangent point and pixel scale (0.186''/pixel) as the CFHTLS T0006 Deep images
All images have a zero point of 30.00 AB: m(AB) = -2.5 x log10(flux) + 30.0
Description of distributed catalogues
Several different kinds of catalogues are provided with this release:
Single band catalogues These catalogues are generated by running sextractor on each input image and weight map. There are three catalogues for J, H and Ks images.
Optically-selected matched aperture chi2 catalogues These catalogues were constructed by using SExtractor in "dual-image mode" using the CFHTLS gri-chi2 image as a detection image. The optical images used were the CFHTLS T0006 Deep 85% seeing images. There are eight catalogues in total for the u, g, r, i, z, J, H and Ks images; in these catalogues the SAME object ID refers to the SAME object.
Infrared-selected matched aperture catalogues These catalogues were constructed by using SExtractor in "dual-image mode" using the near-infrared Ks image as a detection image. There are eight catalogues in total for the u, g, r, i, z, J, H and Ks images; in these catalogues the SAME object ID refers to the SAME object. As before, the optical images used were the CFHTLS-T06 Deep 85% seeing images.
Merged catalogues These catalogues contain a subset of columns from the above catalogues. "Total" (Kron) magnitudes are reported for objects in the detection band; 2" aperture magnitudes are reported in all other bands.
Three-colour JHKs images of the WIRDS fields can be found here: WIRDS_JHK_022559-042940_T0002_2x2.tif WIRDS_JHK_100028+021230_T0002_2x2.tif WIRDS_JHK_141927+524056_T0002_2x2.tif WIRDS_JHK_221531-174356_T0002_2x2.tif
Polygonal mask files indicating the boundaries of the fields (in units of pixels) can be found here: WIRDS_JHK_022559-042940_T0002.reg WIRDS_JHK_100028+021230_T0002.reg WIRDS_JHK_141927+524056_T0002.reg WIRDS_JHK_221531-174356_T0002.reg
Acknowledging WIRDS data
If you use these data or catalogues in a paper you must include the following text, as well as referring to the WIRDS data paper, Bielby et al (in preparation):
Based on observations obtained with WIRCam, a joint project of CFHT,Taiwan, Korea, Canada, France, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX, the WIRDS (WIRcam Deep Survey) consortium, and the Canadian Astronomy Data Centre. This research was supported by a grant from the Agence Nationale de la Recherche ANR-07-BLAN-0228