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Description
The Faint Source Survey (FSS) is the definitive Infrared Astronomical Satellite (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. This increase in sensitivity results from the co-adding of the three separate hours-confirming (HCON) passes over the sky which were used for confirmation and not added together for the Point Source Catalog. The FSC also contains 99,973 infrared sources which are not in the PSC. The FSC contains data for 173,044 point sources in unconfused regions with flux densities typically above 0.2 Jy at 12, 25, and 60 microns, and above 1.0 Jy at 100 microns. The FSS plates are somewhat more sensitive but less reliable than the FSC; typically, only sources with SNR > 5 - 6 in the plates are contained in the FSC. The data products, the processing methods used to produce them, results of an analysis of these products, and cautionary notes are given in the Explanatory Supplement to the IRAS Faint Source Survey. This database table contains the IRAS Faint Source Catalog (FSC) (Version 2.0, released in September 1990) non-associations data. The associations data for the IRAS FSC is contained in the file <a href="https://cdsarc.cds.unistra.fr/ftp/cats/II/156A/assoc.dat.gz">https://cdsarc.cds.unistra.fr/ftp/cats/II/156A/assoc.dat.gz</a> The FSC is limited in galactic latitude to the unconfused regions of sky in which the absolute value of BII is greater than or equal to 10 degrees at 12 and 25 microns and greater than or equal to 20 degrees at 60 microns. Because of the presence of the infrared "cirrus" at 100 microns, the FSC does not contain sources detected ONLY at 100 microns. Sources with a 100 micron detection were included in the catalog if they were bandmerged with high reliability detections at other spectral bands. For the faintest sources, the reliability exceeds 90% at 12 and 25 microns, and 80% at 60 microns. The HEASARC recreated this database table in August 2005, based on the CDS table, in an effort to modernize its parameter names and documentation, as well as to add Galactic coordinates. This is a service provided by NASA HEASARC .
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