Data Release Content

Included tiles

This data release (KiDS-ESO-DR2) consists of the coadded images, weight maps, masks and source lists of the 98 tiles that were completed (i.e. the final data for the tile was obtained) between 1 October 2012 and 31 September 2013. For a table with the coordinates of the tile centers please refer to the data table on this website.
Furthermore, KiDS-ESO-DR2 contains a multiband source catalogue encompassing these tiles, as well as the tiles included in the first data release (KiDS-ESO-DR1), a total of 148 survey tiles. The Source catalog table on this website lists all tiles included in the catalog.

Location of the 50 KiDS-ESO-DR1 tiles (blue) and the 98 KiDS-ESO-DR2 tiles (green); the two KiDS fields (top: KiDS-North; bottom: KiDS-South) are outlined in grey. The multi-band catalog included in KiDS-ESO-DR2 covers all blue and green tiles.

Data products

The following types of data products are provided for the 98 newly released tiles:

• Coadds: photometrically and astrometrically calibrated, stacked images (1 per filter per tile)
• Weights: weight frames (1 for each Coadd)
• Flag images: FITS images with pixel flags in areas affected by bright stars, saturated pixels, reflections, and other artefacts (1 for each Coadd)
• Source lists: lists of sources detected in single Coadds
• Multi-band catalogs: aperture-matched source catalog

This corresponds to a total of 1568 files and a total data volume is 1.4 TB.

The multi-band source catalog covers 148 tiles and is distributed over multiple files: a metadata file describing the catalog contents and one catalog data file per tile. Thus, the total number of files making up the catalog is 149, and the data volume is 11 GB. In total the catalog contains 16,622,442 sources.

Naming convention

The naming convention used for all data products is the following:
KiDS_DR1.0_R.R_D.D_F_TTT.fits,
where R.R and D.D are the RA and DEC of the tile center in degrees (J2000.0) with 1 decimal place, F is the filter (u, g, r, or i), and TTT is the data product type. The value of TTT for the different data products is given in column 4 of the table below.

For example: the r-band stacked image of the tile "KIDS_47.8-31.2" is called KiDS_DR2.0_47.8_-31.2_r_sci.fits and the catalog data file of the same tile KiDS_DR2.0_47.8_-31.2_ugri_src.fits.

Data format

The final calibrated, coadded images have a uniform pixel scale of 0.2 arcsec. The pixel units are fluxes relative to the flux corresponding to magnitude = 0. This means that the effective zeropoint is equal to 0 and the magnitude m corresponding to a pixel value f is:

m = -2.5 log₁₀ f.

The gain varies slightly over the field-of-view because of the zeropoint offsets applied to individual CCDs to homogenize the photometry. An average effective gain is provided in the data table.

An example of a FITS header of a coadded image can be viewed here.

The following table lists the types of data products provided in this release, together with descriptions of the file types and naming conventions used.

Data product	ESO product category name	File type	TTT
Calibrated, stacked images	SCIENCE.IMAGE	FITS image	sci
Weight frames	ANCILLARY.WEIGHTMAP	FITS image	wei
Masks	ANCILLARY.MASK	FITS image	msk
Single-band source lists	SCIENCE.SRCTBL	Binary FITS table	src
Multi-band catalogue data file	SCIENCE.MCATALOG	Binary FITS table	src