FIRST Survey Catalogs

A source catalog including peak and integrated flux densities and size information derived from fitting two-dimensional Gaussians to the sources is generated from the coadded images. The astrometric reference frame of the maps is accurate to 0.05", and individual sources have 90% confidence error circles of radius < 0.5" at the 3 mJy level and 1" at the survey threshold. The survey area has been chosen to coincide with that of the Sloan Digital Sky Survey (SDSS); at the mv~23 limit of SDSS, ~30% of the optical counterparts to FIRST sources are detected. unambiguous optical identifications (<5% false rates) are achievable to mv~24.

A catalog from the 1993 through 2011 images (containing ~946,000 sources and covering ~10,575 square degrees) has been constructed and tested to ensure reliability and completeness. The current version (14mar04) of the catalog is available as either a compressed ASCII file or a FITS binary table. Please read the catalog description for information on retrieving the catalog, the file format and catalog limitations. A paper is available that describes in depth the FIRST catalog construction. The current catalog is most easily accessed through the FIRST Search Page, which can be used to search the FIRST catalog by position and/or by other catalog parameters.

The current sky area covered is shown in the coverage maps below:

Northern coverage map

Southern coverage map

These coverage maps are available in several different formats, including FITS versions that give the rms noise as a function of sky position.

Previously released versions of the catalog are still accessible; see the catalog history for information on changes in the released versions.