GaBoDS/WFI data release: Version 1.0

13 April 2006

As part of the ESO Deep Public Survey (DPS), optical imaging observations were carried out in U, B, V, R, I bands, using the Wide Field Imager (WFI) instrument mounted at the 2.2m telescope at La Silla, Chile. This survey consisted of three square degrees in three well-separated regions (Deep1, Deep2 and Deep3) split into 4 adjacent WFI pointings (named a, b, c, d). The Garching-Bonn Deep Survey (GaBoDS) combines the data from this survey with data from most other ESO programmes that coincide with the original DPS regions, up until December 2005.

The resulting data were obtained under the two large programmes 164.O-0561 and 169.A-0725 (P.I. Krautter for both) and, moreover, under the programmes 67.A-0244 (P.I. Schneider) and 075.A-0168 (P.I. Hildebrandt). For the field Deep2c data from the programmes 168.A-0485 (P.I. Cesarsky), 64.H-0390 (P.I. Patat), 66.A-0413 (P.I. Clocchiatti), 68.D-0273 (P.I. Cappellaro), 68.A-0443 (P.I. Clocchiatti), 70.A-0384 (P.I. Vanzi), and 74.A-9001 (P.I. Kuijken) were added, as well as the WFI commissioning data and data from the COMBO17 survey (P.I. Meisenheimer).

These data were reduced with the THELI reduction pipeline (Erben et al. 2005, Astron. Nachr., 326, 432) at the 'Argelander-Institut für Astronomie' (AIfA), Universität Bonn. This data release includes 63 images in 13 fields and has been prepared by the Advanced Data Products group at ESO according to standards to be incorporated into the future VO-compliant Science Archive.

Seven fields (~2 square degrees) are covered in UBVRI, one field (~0.3 square degrees) is covered in BVRI, two fields (~0.6 square degrees) have data in three bands and three fields (~0.9 square degrees) have data in only one band. The different fields are rather heterogeneously deep, but typical 5σ Vega limiting magnitudes in a circular aperture of 2 arcseconds are: U ~ 25.3, B ~ 26.2, V ~ 25.8, R ~ 25.3, I ~ 24.3

The properties of the images are described in detail in Hildebrandt et al. 2006, A&A, 452, 1121 and more information can be found at http://marvin.astro.uni-bonn.de/DPS/.

Overview and field layout

Positions of the twelve DPS fields and two mispointings (Deep1e and Deep1f). The region Deep1 overlaps with the ATESP radio survey and the field Deep2c is centred on the Chandra Deep Field South.
[Click to get the full size layout]

Release content

Summary of reduced WFI fields

The released optical images from the DPS regions reduced with the THELI pipeline are tabulated to the right, consisting of 68 images in U/50 (11), U/38 (4), B/99 (11), B/123 (1), V/89 (11), Rc/162 (15), Ic/lwp (11) and I/203 (2) filters. The coaddition ID in column three is an identifier to distinguish different coadditions of a field, based on the conditions imposed. The Vega limiting magnitudes in column six correspond to 5σ sky level measured in a circular aperture of 2" diameter. The grades in column seven are estimated from visual inspection of the coadded images. Grade "A" is assigned to an image with no special features and an appearance typical for the particular band. Grade "B" is assigned to an image with cosmetic defects. Nevertheless also the grade "B" images are fully usable for most scientific purposes. The same table is also available in ASCII format.

[click to see the full table]

Release notes

For information about the data reduction method, astrometric solution and photometric zeropoints, please see the papers mentioned above.

Data format

The data files in this release come in pairs: one is the science frame, the second one is the corresponding weight map (*.weight.fits) defined as a variance map (e.g. it should be used with SExtractor using the parameters: -WEIGHT_IMAGE weight_map.fits -WEIGHT_TYPE MAP_WEIGHT).

The following file naming convention has been adopted:

    GaBoDS_WFI_xx-y_f_v.fits
    GaBoDS_WFI_xx-y_f_v.weight.fits

for the field name <xx> and coaddition ID <y> in the filter <f> and the respective weight map. For those files that are part of the original release, <v> will be v1.0; for the files that have been added in this release <v> will be v1.1.

Additionally, field names can be found in the OBJECT keywords in the FITS headers.

Data retrieval

Please make your selection on the page linked to below.

Complete package 126 files (46.32 GB)

Acknowledgements

When using data products provided in this release, we request that authors refer to the papers Hildebrandt et al. 2006, A&A, 452, 1121 and Erben et al. 2005, Astron. Nachr., 326, 432. In addition, please also use the following statement in your articles when using these data:

Based on observations made with ESO Telescopes at the La Silla or Paranal Observatories.