LAMBDA News
Infrared Astronomical Satellite, IRAS
Description
The Faint Source
Survey (FSS) is the definitive IRAS data set for faint point
sources. The FSS was produced by point-source filtering the
individual detector data streams and then coadding those data
streams using a trimmed-average algorithm. The resulting images,
or plates, give the best estimate from the IRAS survey data
of the point source flux density at every surveyed point of
the sky. The Faint Source Catalog (FSC) is a compilation of
the sources extracted from the
FSS plates that have met reasonable reliability requirements.
Averaged over the whole catalog, the FSC is at least 98.5%
reliable at 12 and 25 microns, and ~94% at 60 microns. For
comparison, the IRAS Point
Source Catalog (PSC) is > 99.997% reliable, but the
sensitivity of the FSC exceeds that of the PSC by about a
factor of 2.5. The FSC contains data for 173,044 point sources
in unconfused regions with flux densities typically greater
than 0.2 Jy at 12, 25, and 60 microns and greater than 1.0
Jy at 100 microns.
Sources with SNR > 3 but which do not meet the reliability
requirements of the FSC are cataloged in the Faint
Source Reject File (FSR). The FSR contains data for 593,516
sources. Moshir et al. (1992) describe the processing methods
used to produce the FSR and give cautionary notes about its
interpretation.
Reference:
Moshir, M. et al. 1992, Explanatory Supplement to the IRAS
Faint Source Survey, version 2, JPL D-10015 8/92 (Pasadena:
JPL).
Version and release date: 2.0, 1990 Sept
