The First FIRST Source Catalog
Session 8 -- Radio Surveys and Techniques
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

## [8.03] The First FIRST Source Catalog

D.J. Helfand (Columbia U.), R.H. Becker (U.C. Davis \& IGPP/LLNL), R.L. White (STScI), Y. Fang (Columbia U.), R.G. McMahon (IOA, Cambridge), M.L. Gregg (IGPP/LLNL)

We have constructed a preliminary radio source catalog from the first set of FIRST Survey images which cover $\sim 300$ square degrees of sky in a strip passing through the North Galactic Pole. The 28,000 sources form a sample complete to a peak flux density at 20~cm of $<1$ mJy, and all have positions accurate to better than $1^{\prime\prime}$ (90\% confidence). Individual postage stamp'' images of each source have been produced with a pixel size of $1.8^{\prime\prime}$ (the FWHM of the VLA B-configuration synthesized beam, used for these observations, is $5.4^{\prime\prime}$). In addition, we have extracted from the Cambridge APM scans of the POSS I Palomar plates a catalog of magnitudes and colors for all optical objects falling within $10^{\prime\prime}$ of each radio source position; over 4000 radio sources have been optically identified (offsets $<1.5^{\prime\prime}$) with a chance coincidence rate of $<5\%$.

This catalog represents an improvement of a factor of $\sim 50$ in both angular resolution and flux density over the best existing radio catalogs. We examine the source content of the catalog, reporting on the incidence and properties of double and triple radio sources, the source clustering statistics, and the samples of head-tail sources, quasar candidates, and other source classes derived from the morphological and optical color information we have produced. The use of the survey to define flux-limited samples of stellar radio sources, BL Lac objects, distant clusters, and other systems of interest will be illustrated.