[From the ADC CD-ROM; originally from the Explanatory Supplement to the IRAS Faint Source Survey]
The FSC was produced in "long" and "short" versions, the long version containing more detailed information about the processing history of each source. The "short" FSC, available here, is in FITS table format with the information about associations of FSC sources with sources in other astronomical catalogs in a separate file.
The catalog consists of the following:
Specifically, the formats of the files are as follows:
Table 1. Format of FSC Data File for Short FSC File Start Byte Name Description Units Format 0 NAME * Source Name _ 12A1 12 RAHR Right Ascension 1950 Hour of time I2 14 RAMIN Right Ascension 1950 Minute of time I2 16 RASEC * Right Ascension 1950 deci-Second of time I3 19 DECSGN * Declination Sign ± A1 20 DECDEG Declination 1950 Arc Degree I2 22 DECMIN Declination 1950 Arc Minute I2 24 DECSEC * Declination 1950 Arc Second I2 26 UNCMAJ * Uncertainty ellipse major axis Arc Second I3 29 UNCMIN * Uncertainty ellipse minor axis Arc Second I3 32 POSANG * Uncertainty ellipse position angle Degree (East I3 of North) 35 NOBS *+ Number of times observed in _ 4I3 each band 47 FNU *+ Flux densities (1 value per Jansky (10^-26 4E9.3 band, non-color corrected) W m-^2 Hz^-1) 83 FQUAL *+ Flux density quality _ 4I1 (1 value per band) 87 RELUNC + Percent relative flux density _ 4I3 uncertainties (1 value/band) 99 MINREL * Minimum percent reliability _ I2 101 MEDSNR *+ SNR in each band _ 4E7.1 129 LOCSNR *+ Local SNR in each band _ 4E7.1 157 AREA *+ Number of pixels above _ 4I3 threshold in each band 169 CATNBR * No. of nearby catalog sources _ I2 171 EXTNBR *+ No. of nearby extractions _ 4I2 in each band 179 CIRRUS * No. of nearby 100-micron-only _ I2 extractions 181 CONFUSE * Confusion flag (1 flag/band, _ A2 hex encoded) 183 NOISCOR + Noise correction factor _ 4F5.2 (1 value per band) 203 NID * No. of positional associations _ I2 205 IDTYPE Type of object _ I2 207 NOISRAT Ratio 85% to 68% of flux _ 4F5.3 distribution (1 value per band) 227 SPARE - 13A1 * Quantities listed in microfiche version of catalog + In the FITS header, these quantities are suffixed by the wavelength. Example: FNU(4) is given as FNU_12, FNU_25, FNU_60, and FNU_100. Table 2. Format of Association Data for FSC File Start Byte Name Description Units Format 0 NAME * Source Name _ 12A1 12 RECNO * Record No. in main data table _ I6 18 CATNO * Catalog No. _ I2 20 SOURCE * Source ID _ 15A1 35 TYPE * Source Type/Spectral Class _ 5A1 40 RADIUS * Radius vector from IRAS Arc Second I3 source to association 43 POS Position angle from IRAS Degree (East I3 source to association of North) 46 DSTMAJOR Distance from IRAS source to Arc Second I3 association along the IRAS position error major axis 49 DSTMINOR Distance from IRAS source to Arc Second I3 association along the IRAS position error minor axis 52 FIELD1 + Object field #1 Catalog I4 (magnitude/other) dependent 56 FIELD2 + Object field #2 Catalog I4 (magnitude/other) dependent 60 FIELD3 Object field #3 Catalog I4 (magnitude/other) dependent * Quantities listed in printed version of catalog + FIELD1 is listed in microfiche version of catalog, except for catalogs 2 and 19, where FIELD2 is listed.
Table V.C.2 of the Explanatory Supplement to the IRAS Faint Source Survey gives a sample of the header for the non-association data and Table V.C.3 gives a sample of the header for the association data. Tables 1 (FSC data) and 2 (association data) describe each entry in the short catalog file. All of this information is contained in the actual FITS headers, but is presented here in an easier-to-read format. Those columns that are also included in the microfiche version are marked. Each catalog entry requires 240 bytes of ASCII data for the non-association data and NID x 64 bytes of ASCII data for the association data. In these tables the column "Format" refers to the length and type of the (FORTRAN) character field used to read or write each entry.
In general, for quantities that have a value in each wavelength band, subscripts or array indices range from 1 to 4 and refer, respectively, to 12, 25, 60 and 100 microns. A number of the flags discussed below have values in each of the four wavelength bands. For compactness these are encoded into a single base-16 (Hex) digit (values 0-F) in the following manner. The four bits of the hex digit correspond to the four wavelength bands with bit 0 (Least Significant Bit) for 12 microns, bit 1 for 25 microns, bit 2 for 60 microns and bit 3 for 100 microns. The presence of a flag in a band is denoted by setting its bit to 1. Thus a flag set at 12 and 25 microns would have a value of 0011=3(Hex) while a flag set at 25, 60 and 100 microns would have a value of 1110=E (Hex). A flag encoded in this manner will be referred to as "hex-encoded by band".
The remainder of this section discusses individual entries in the catalog.
Table 3. Meaning of the Source Association Fields Catalog Field and Meaning 1 GCVS Type Blank Field1 Code gives meaning for Fields 2-3 if Field1 = 1 Field2 and Field3 are B mag [decimag] at max, min if Field1 = 2 Field2 and Field3 are V mag [decimag] at max, min if Field1 = 3 Field2 and Field3 are photographic mag [decimag] at max,min if Field1 = 4 Field2 and Field3 are estimated V mag [decimag] at max,min if Field1 = 5 Field2 is -999 and Field3 is 0 2 Dearborn Type Blank Obs. Field1 Code for Field2 (1,2) Field2 if Field1 is 1, Field2 is red magnitude [decimag] if Field1 is 2, Field2 is -999 Field3 0 3 Revised Type Blank AFGL Field1 Magnitude at 4.2 microns [decimag] Field2 Magnitude at 11 microns [decimag] Field3 Magnitude at 27 microns [decimag] 4 2-micron Sky Type Blank Survey Field1 K magnitude [decimag] Field2 I magnitude [decimag] Field3 0 5 Globules Type Blank (Wesselius) Field1 -999 Field2 Minimum diameter [arcsec] Field3 Maximum diameter [arcsec] 6 R C 2 Type Blank Field1 Harvard V magnitude [decimag] Field2 B_T [decimag] Field3 D_o [arcsec] 7 Stars with Type Blank em. lines Field1 V magnitude [decimag] Field2 -999 Field3 0 8 Equatorial Type Blank IR Cat. Field1 Flux density [10^-16 W cm^-2 micron] at 2.7 microns Field2 -999 Field3 0 9 UGC Type Blank Field1 Zwicky magnitude [decimag] Field2 Minimum diameter [arcsec] in B Field3 Maximum diameter [arcsec] in B 10 MCG Type Blank Field1 -999 Field2 Minimum diameter [arcsec] in B Field3 Maximum diameter [arcsec] in B 11 Strasbourg Type Blank Planetary Nebulae Field1 V magnitude of Nebula [decimag] Field2 B magnitude of Central Star [decimag] Field3 Minimum diameter of Nebula [arcsec] 12 Zwicky Type Blank Field1 Zwicky magnitude [decimag] Field2 -999 Field3 0 13 SAO Type Spectral Type Field1 V magnitude [decimag] Field2 p_g magnitude [decimag] Field3 0 14 ESO/ Type First 3 characters of object type UPPSALA Field1 B magnitude [decimag] Field2 Maximum diameter [arcsec] Field3 Minimum diameter [arcsec] 15 Bright Type Spectral Type Stars Field1 V magnitude [decimag] Field2 B-V [centimag] Field3 U-B [centimag] 16 Suspected Type Spectral Information Var. Field1 V magnitude at maximum [decimag] Field2 -999 Field3 0 17 Carbon Type Spectral Type (may be truncated) Stars Field1 p_g magnitude [decimag] Field2 V magnitude [decimag] Field3 I magnitude [decimag] 18 Gliese Type Spectral Type (may be truncated) Field1 V magnitude [decimag] Field2 B-V magnitude [millimag] Field3 U-B magnitude [millimag] 19 S Stars Type Blank Field1 p_g magnitude [decimag] Field2 V magnitude [decimag] Field3 I magnitude [decimag] 20 Parkes HII Type Blank Survey Field1 -999 Field2 Minimum diameter [arcsec] Field3 Maximum diameter [arcsec] 21 Bonn HII Type Blank Survey Field1 Flux density at 4.875 GHz (Jy) Field2 Diameter [arcsec] Field3 0 22 Blitz Type Blank Field1 Diameter [arcsec] Field2 V_CO [km/s] Field3 Peak T_A [Kelvin] 23 OSU Type Blank Field1 -999 Field2 -999 Field3 Diameter [arcsec] 24 IRC Type C if 2.2-microns sources are possibly w/good pos. confused, blank otherwise Field1 Right ascension difference (IRC-IRAS ) [deciseconds of time] Field2 Declination difference (IRC-IRAS ) [arcsec] Field3 0 25 DDO Type Blank Field1 -999 Field2 -999 Field3 0 26 Arp Type Blank Field1 -999 Field2 -999 Field3 0 27 Markarian Type Blank Field1 -999 Field2 -999 Field3 0 28 Strong Type Object type (GAL or QSO) 5 GHz Field1 V magnitude [decimag] Field2 5 GHz flux density [deciJy] Field3 0 29 Veron-Cetty Type Object classification Veron Field1 V magnitude [decimag] Field2 Redshift x 1000 Field3 0 30 Zwicky Type Blank 8 Lists Field1 -999 Field2 -999 Field3 0 31 VV Type Blank Field1 Special flag (see below) Field2 -999 Field3 0 32 IRAS Small- Type Blank Scale Structure Field1 Hex-coded bands Field2 -999 Field3 -999 39* OSU Type Blank * Radio * Field1 Frequency * Field2 Flux [deciJy] * Field3 0 * 40 Michigan Type Class** * Spectral * Field1 Mag [decimag] * Field2 HD number [low byte] * Field3 HD number [high byte] * 41 Serendipitous Type Blank * Survey * Field1 Hex-coded SSC bands * Field2 First SSC flux density [mJy]*** * Field3 Second SSC flux density * 42 PSC II Type Blank * Field1 Hex-coded PSC bands * Field2 First PSC flux density [mJy]*** * Field3 Second PSC flux density [mJy] * 48 Virgo Type Class** * Cluster * Catalog * Field1 B_T magnitude [decimag] * Field2 Heliocentric velocity [km/s] * (-999 when not available) * Field3 Source size 100 x log D_est(.1 arcsec) 49 Dressel Type Blank and Condon Field1 -999 Field2 -999 Field3 -999 50 Asteroids Type Blank Field1 -999 Field2 First four digits of crossing time [seconds, since 1980.0] Field3 Last four digits of crossing time * Catalog numbers 33-38 reserved for internal use. ** Source name and type fields were combined to hold spectral type and class (Catalog 40), or object classification (Catalog 48). *** Flux densities given are the first two measurements in order from 12 to 100 microns. VV Catalog Flags (Catalog 31) 10 VV 10 has the same coordinates as VV29 in the VV Atlas. The UGC was used to confirm that the coordinate is correct for VV 29 and erronerous for VV 10. The UGC position for VV 10 = TGC 10814 was adopted. 11 The VV position is substantially different (> 400 arcsec) from positions for the object in other catalogs. The VV position has been assumed to be in error because two or more other catalogs agree on a different position. The UGC position has been adopted. 12 Same as for 11, but the OSU position has been adopted. 13 The position in the VV Atlas, and the position listed for the VV object in the OSU are in disagreement. The true position has been established to be close to that of the OSU by the use of overlay transparencies on the POSS. The OSU position has been adopted. 14 Same as for 13, but the OSU position is not very good either, so a new position has been measured (accurate to about 1 arcsec.) -999 No information given
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