4. Data organization
4.1. Catalogue contents
Table 1 gives an overview of the contents of an individual record in the preliminary database of DENIS point sources.
Table 1. Summary of catalogue record contents for DENIS point sources
4.2. Data access
The released data are being made available through the CDS Web server at the following address:
This server provides access to DENIS documentation, including scientific reports, list of publications, etc., and to the publicly released data sets. The database implementation benefits from the CDS environment (Genova et al. 1998): SIMBAD name resolver, VIZIER query engine (Ochsenbein 1998), ALADIN cross-identification atlas, etc.
4.3. Query modes
An interactive sky map provides a graphical access to individual strips, while an auxiliary database provides information about night and strip qualities. Strips can be searched directly by position or strip or slot number.
In addition an optimized query mechanism provides access to individual data records (including source number, position, I, J, magnitudes, and estimated errors, and additional flags related to the source extraction) for the extracted point sources. The first release of the preliminary database includes about 17 million entries in 102 strips.
Queries can be made for all DENIS sources around a given position (center and radius, where the center is to be specified either as J2000 coordinates, or by the name of a central object to be resolved by SIMBAD ). Selection of objects in the colour-colour diagrams of specified strips is also possible.
Finally, the DENIS point source database is also available through the VIZIER catalogue service, and through the ALADIN interactive sky atlas, where additional query modes and functionalities are available.
4.4. Future evolutions
The DENIS point source data server at CDS will continue to evolve in the future, with newly reduced data being gradually incorporated.
Changes in the data reduction pipeline will be posted in the corresponding information pages.
New features for an improved support of the query mechanism and source selection will also be made available as they are being developed. A mirror copy of the publicly released 2MASS J, H, data (see e.g. Skrutskie 1998) is planned to become available, in parallel, at CDS, for easier cross-comparison.
In complement to the CDS services, observational DENIS data for galaxies are also being made available through the Lyon-Meudon Extragalactic Database (LEDA; see Sect. 5.6, below). DENIS data of Asymptotic Giant Branch (AGB) stars recognized as associated to sources included in the ASTRID database are also gradually integrated into this base.
© European Southern Observatory (ESO) 1999
Online publication: August 25, 1999