The FIRST Survey Catalog: 08Jul16 Version

A catalog for the north and south Galactic caps (816,331 sources), derived from the 1993 through 2004 observations, is available as a gzip-compressed ASCII file (catalog_08jul16.bin.gz) and as a FITS binary table (first_08jul16.fits.gz). The file size is 35 Mbytes compressed (131 Mbytes uncompressed) for the ASCII version and 45 Mbytes compressed (82 Mbytes uncompressed) for the FITS version. The catalog covers a total of about 9055 square degrees of sky (8444 square degrees in the north Galactic cap and 611 square degrees in the south Galactic cap.)

See the coverage maps for more details of the area covered. Both the northern and southern areas were chosen to coincide approximately with the area covered by the Sloan Digital Sky Survey.

This version of the catalog has a region along the equatorial strip (RA = 21.3 to 3.3 hrs, Dec = -1 to 1 deg) where the detection threshold is deeper than 1 mJy because two epochs of observation were combined. The typical detection threshold in this region is 0.75 mJy. There are approximately 4,500 sources below the 1 mJy threshold used for all previous versions of the catalog.

This catalog was created by rerunning our source detection routine HAPPY on all the coadded images in order to produce a more consistent source lists. The small changes due to inevitable evolution in the software and hardware being used created corresponding small differences between this catalog and previous versions, even in regions where the images have not changed. The great majority of the sources are identical -- ~80% of the sources have positions identical to those in the last version of the catalog. ~1.5% of the sources from the old catalog do not appear in this version; such sources are generally in images with new data, are very near the detection threshold, or are in complex regions that get decomposed differently in the two catalogs.

The catalog is on-line and can be searched using the FIRST Search Engine. However, for large-scale investigations it will be necessary to obtain the complete catalog. This document describes the catalog format.

The catalog is sorted by decreasing declination and has the following format:

                                                                                                                ------SDSS------ ------GSC2------ -----2MASS----
   RA           Dec        P(S)    Fpeak      Fint    RMS     Maj    Min   PA    fMaj   fMin   fPA Field         #  Sep    i  Cl  #  Sep    F  Cl  #  Sep    K  
14 35 55.835 +64 34  4.69 0.014     1.75      1.83   0.158   1.95   0.00  14.9   5.74   5.29  14.9 14360+64240M  1  4.76 20.60 g  0 99.00 99.00 -  0 99.00 99.00
11 27 20.244 +64 32 34.60 0.576     1.03      0.70   0.143   0.00   0.00 113.3   4.86   4.10 113.3 11300+64240M  1  5.36 18.44 s  1  5.17 19.26 g  1  5.27 15.47
06 57 23.618 +64 32 33.37 0.014     1.21      1.75   0.137   5.80   0.00 147.5   7.93   5.33 147.5 07000+64243J -1 99.00 99.00 -  0 99.00 99.00 -  0 99.00 99.00
13 21 43.254 +64 32 30.72 0.289     1.16      4.31   0.147  10.96   7.04  21.5  12.22   8.88  21.5 13240+64240M  0 99.00 99.00 -  0 99.00 99.00 -  0 99.00 99.00
10 07 16.439 +64 32 30.69 0.014     1.35      0.99   0.148   1.58   0.00   7.6   5.62   3.79   7.6 10060+64240M  1  1.29 20.68 s  1  0.76 99.99 g  0 99.00 99.00
Note that this format differs from that in previous versions of the catalog. The P(S) column, which indicates the probability that the source is a sidelobe, replaces the previous binary sidelobe flag column. The columns following the field name are new and give information on counterparts to the FIRST source in the SDSS DR6 catalog, the Guide Star Catalog 2.3.2, and the 2MASS catalog. These new parameters are described in detail below in the description of the P(S) column and the counterparts columns.


The catalog history page describes previously released versions of the FIRST catalogs, which are still available for historical purposes. We recommend that the new catalog be used where possible for all projects.