The FIRST Survey Catalog, Version 12Feb16

The Faint Images of the Radio Sky at Twenty centimeters (FIRST) began in 1993. It uses the VLA (Very Large Array, a facility of the National Radio Observatory (NRAO)) at a frequency of 1.4GHz, and it is slated to 10,000 deg^2^ of the North and South Galactic Caps, to a sensitivity of about 1mJy with an angular resolution of about 5''. The images produced by an automated mapping pipeline have pixels of 1.8'', a typical rms of 0.15mJy, and a resolution of 5''; the images are available on the Internet (see the FIRST home page at sundog.stsci.edu/ for details).

The source catalogue is derived from the images. This catalog from the 1993 through 2011 observations contains 946,464 sources from the north and south Galactic caps. It covers a total of 10,635 square degrees of the sky (8444 square degrees in the north and 2191 square degrees in the south.) The catalog format differs from the previous version: The contents of the sidelobe flag column has changed to a sidelobe probability estimate, and columns have been added with information on optical and infrared counterparts from the SDSS and 2MASS catalogs.