Table information for 'cars.products'

General

Table Description: A view combining most of the CARS-related products.

This table is not available for ADQL queries and through the TAP endpoint.

Resource Description: Images and data from from the CFHTLS archive research survey, a multi-band dataset spanning 37 square degrees of sky in high galactic latitudes.

For a list of all services and tables belonging to this table's resource, see Information on resource 'CARS survey data'

Citing this table

This table has an associated publication. If you use data from it, it may be appropriate to reference 2009A&A...493.1197E (ADS BibTeX entry for the publication) either in addition to or instead of the service reference.

To cite the table as such, we suggest the following BibTeX entry:

@MISC{vo:cars_products,
  year=2009,
  title={{CARS} survey data},
  author={Erben, T. and Hildebrandt, H. and Lerchster, M. and Hudelot, P. and Benjamin, J. and van Waerbeke, L. and Schrabback, T. and Brimioulle, F. and Cordes, O. and Dietrich, J. P. and Holhjem, K. and Schirmer, M. and Schneider, P.},
  url={http://dc.zah.uni-heidelberg.de/tableinfo/cars.products},
  howpublished={{VO} resource provided by the {GAVO} Data Center}
}

If you use the CARS products for your own research, please give proper acknowledgment to CADC, the CFHTLS project and the publication 2009A&A...493.1197E

Resource Documentation

These services deliver products from the CFHTLS-Archive-Research Survey (CARS). The survey currently offers derived products from 37 sq. degrees of the Wide part from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The main documentation for the products, its creation and its content is the publication 2009A&A...493.1197E. Here, we discuss some points which are not evident from this publication.

AVAILABLE DATA PRODUCTS

For each 1 sq. deg. CARS pointing we currently offer the following products (we discuss them on the example of the CARS pointing W1m0p1); a typical file is named W1m0p1_izrgu.V1.7A.final.cat. The name contains the following information:

The individual files we offer are:

W1m0p1_izrgu.V1.7A.final.cat
object catalogue in FITS binary format; beware that they are very big and cumbersome to handle if you do not have efficient tools to work on big FITS binary tables! (typical file size per field: 0.5GB!)
W1m0p1_izrgu.V1.7A.final.asc.gz
An ASCII version of W1m0p1_izrgu.V1.7A.final.cat containing a subset of the most important catalogue quantities. This catalogue should be sufficient for most users. The main content of the catalogue can also be queried in the cat service. (typical gzipped file size per field: 20MB)
W1m0p1_izrgu.V1.7A.final.reg.gz

An ASCII ds9 region file containing saoimage/ds9 polygon entries (in pixel coordinates). They represent the CARS image masks described in Sect. 3.4 of 2009A&A...493.1197E. Polygons originating from different masking procedures are encoded with different colours (look at expressions such as '# color=yellow' at the end of each line). We offer this file so that interested users can construct own masks containing only parts of our global MASK key. (typical gzipped file size per field: 1MB)

The colour coding in these files is as follows:

  • yellow: masks from our object density analysis and stars identified in the USNO-A2 catalogue
  • green: stars identified in the GSC1 and GSC2 cataogues
  • magenta: masks around extended haloes of bright stars
  • red: masks from our asteroid track analysis

W1m0p1_irg.V1.7A.truecol.jpg

low resolution true colour i', r' and g' JPG image of the CARS field. These images allow a quick look at the data but they are probably not suitable for high-quality poster print-outs. (typical file size per field: 10MB)
W1m0p1_izrgu.V1.7A.masks.obj.jpg

low resolution JPG image showing object positions and object masks overlayed on the i'-band image. It allows a quick-look at field-layout and object positions. (typical file size per field: 3MB)

The colour coding in this is:

  • green: areas excluded from scientific analysis by our MASK key
  • yellow: stellar sources (SExtractor CLASS_STAR >=0.95)
  • red: galaxies with high-confidence photo-z estimates: (SExtractor CLASS_STAR < 0.95; reliable object photometry in five bands; BPZ ODDS quality parameter > 0.9); see also Sect. 4 of 2009A&A...493.1197E
  • blue: all other galaxies (SExtractor CLASS_STAR < 0.95)

CATALOGUE QUANTITIES

See 2009A&A...493.1197E, in particular Sect. 4, and the SExtractor Users manual for a description of most catalogue entries. Also see the table notes.

CURRENT COVERAGE

CARS coverage

Columns

Sorted by DB column index. [Sort alphabetically]

NameTable Head DescriptionUnitUCD
fieldKey Field CARS field designation N/A meta.id
bandpassId Bandpass Freeform name of the bandpass used N/A instr.bandpass
ncombine Combined Number of individual frames in this stack N/A meta.number
texptime Tot. Exposure Total Exposure Time s time.duration;obs.exposure
magzp Mag. ZP AB Magnitude Zeropoint mag phot.mag;arith.zp
magzperr Err. Mag. ZP Estimated Magnitude Zeropoint Error mag stat.error;phot.mag;arith.zp
seeing Seeing Measured image seeing arcsec instr.obsty.seeing
seeingerr Err. Seeing Measured image Seeing error arcsec stat.error;instr.obsty.seeing
accref Product key Access key for the data N/A meta.ref.url
accsize File size Size of the data in bytes byte VOX:Image_FileSize
weightlink Weights Weight FITS N/A N/A
weightsize Size(Weights) Size of weight FITS N/A N/A
regionlink DS9 masks Image masks as DS9 regions N/A N/A
regionsize Size(masks) Size of DS9 region file N/A N/A
truecollink Preview Preview color image made of i,r, and g band images N/A N/A
masklink JPEG masks Mask preview as JPEG N/A N/A
catlink Object catalogue FITS catalogue of objects in this field N/A N/A
catsize Size(cat.) Size of FITS catalogue of objects in this field N/A N/A

Columns that are parts of indices are marked like this.

Other

The following services may use the data contained in this table:

VOResource

VO nerds may sometimes need VOResource XML for this table.