Richard L. White
Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, rlw@stsci.edu
Robert H. Becker
Physics Dept., University of California, Davis, CA 95616
and IGPP/Lawrence Livermore National Laboratory, bob@igpp.llnl.gov
David J. Helfand
Astronomy Dept., Columbia University, New York, NY 10027, djh@carmen.phys.columbia.edu
Michael D. Gregg
IGPP/Lawrence Livermore National Laboratory, gregg@igpp.llnl.gov
We present a catalog of 138,665 radio sources derived from the initial
1550 square degrees of the FIRST survey. The survey parameters are
reviewed and a map depicting the coverage for the first two observing
sessions is presented. We then describe in detail our algorithm for
radio source detection and parameterization, as well as our procedures
for constructing the final catalog. The results of extensive tests for
astrometric and photometric accuracy, as well as for uncertainties in
source extent and morphological characterization are presented. Source
positions are all good to better than 
, and the flux density
scale is accurate to 5%; our elliptical Gaussian fitting procedure is
shown both to provide a high-fidelity representation of source
morphology for most objects, and to characterize correctly bright
sources extended on scales down to 
the synthesized beam size
of 
. We use the catalog to construct a 
relation for 20-cm radio sources over four decades of flux density,
finding excellent agreement with previous determinations from smaller
surveys. As one example of the catalog's utility, we present
comparisons with the Guide Star Catalog, the IRAS Faint Source catalog,
and the ROSAT WGA catalog, identifying radio counterparts to thousands
of the objects. Complete instructions for access to this FIRST catalog
and subsequent updates thereto are provided.
Published in
The Astrophysical Journal, 475, 479 (1997)
© 1997 The American Astronomical Society
Keywords: catalogs -- galaxies: quasars: general -- infrared: galaxies -- X-rays: galaxies -- radio continuum: galaxies -- radio continuum: stars -- surveys
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