IRAS Point Source Catalog - Format Description[Adapted from the Explanatory Supplement] The catalog is divided into two files. The first contains the 252,889 sources arranged in order of increasing right ascension and occupies 37.5 Mbyte. The second contains records of 142,228 positional associations and is 7.5 Mbyte long. Tables 1 and 2 describe each entry in the files. In the 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. Hex Encoding. 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 (Table 3). 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 source with a particular flag, e.g. CONFUSE, set at 12 and 25 microns would have CONFUSE = 0011 = 3 (Hex) while one confused in 25, 60 and 100 microns would have CONFUSE = 1110 = E (Hex). A flag encoded in this manner is referred to as "hex-encoded by band". Table 1. Format of Point Source Catalog Data File Start Byte Name Description Units Format 00 NAME [1] Source Name --- 11A1 11 HOURS Right Ascension 1950. Hours I2 13 MINUTE Right Ascension 1950. Minutes I2 15 SECOND [1] Right Ascension 1950. deci-Seconds I3 18 DSIGN [1] Declination Sign ± A1 19 DECDEG Declination 1950. Arc Deg I2 21 DECMIN Declination 1950. Arc Min I2 23 DECSEC [1] Declination 1950. Arc Sec I2 25 MAJOR [1] Uncertainty ellipse Arc Sec I3 major axis 28 MINOR [1] Uncertainty ellipse Arc Sec I3 minor axis 31 POSANG [1] Uncertainty ellipse Degrees I3 position angle (East of North) 34 NHCON [1] Number of times observed --- I2 (<25) 36 FLUX [1] Averaged non-color corrected Jansky 4E9.3 flux densities (1 value per (1.0E-26 W/m**2/Hz) band) 72 FQUAL [1] flux density quality. --- 4I1 (1 value per band) 76 NLRS Number of significant LRS --- I2 spectra 78 LRSCHAR [1] Characterization of averaged --- 2A1 LRS spectrum. 80 RELUNC [1] percent relative flux density --- 4I3 uncertainties (1 value per band). 92 TSNR ten times the minimum signal- --- 4I5 to-noise ratio in each band 112 CC [1] point source correlation --- 4A1 coefficient (1 value per band). 116 VAR [1] percent Likelihood of I2 Variability 118 DISC Discrepant Fluxes flag --- A1 (one per band, hex-encoded) 119 CONFUSE [1] Confusion flag (1 flag --- A1 per band, hex-encoded) 120 PNEARH [1] Number of nearby hours- --- I1 confirmed point sources 121 PNEARW [1] Number of nearby weeks- --- I1 confirmed point sources 122 SES1 [1] Number of seconds-confirmed nearby --- 4I1 small extended sources. (1 value per band) 126 SES2 [1] Number of nearby weeks- --- 4I1 confirmed small extended sources. (1 value per band) 130 HSDFLAG [1] Source is located in high --- A1 source density bin. (1 value per band, hex-encoded) 131 CIRR1 [1] Number of nearby 100 micron --- I1 only WSDB sources 132 CIRR2 [1] Spatially filtered 100 micron --- I1 sky brightness ratio to flux density of point source (see text) 133 CIRR3 Total 100 micron sky MJy/sr I3 surface brightness 136 NID [1] Number of positional --- I2 (<25) associations. 138 IDTYPE Type of Object --- I1 140 MHCON Possible number of HCONs --- I2 142 FCOR Flux correction factor applied --- 4I4 (times 1000, 1 value per band) 158 SPARE 3 Spare blanks --- 3A1 Table 2. Format of Point Source Associations File Start Byte Name Description Units Format 00 NAME IRAS source name --- A11 11 RECNO Record Number of source in data file --- I6 18 CATNO [1] Catalog number --- I2 20 SOURCE [1] Source ID --- 15A1 35 TYPE [1] Source Type/Spectral Class --- 5A1 40 RADIUS1 Radius Vector from IRAS Arc Sec I3 Source to Association 43 POS Position Angle from IRAS Degrees E I3 Source to Association of N. 46 FIELD1 [2] object field #1 catalog I4 (magnitude/other) dependent 50 FIELD2 [2] object field #2 catalog I4 (magnitude/other) dependent 54 FIELD3 object field #3 catalog I4 (size/other) dependent [1] Quantities listed in printed version of catalog. [2] FIELD1 is listed in printed version of catalog, except for catalogs 2 and 19, where FIELD2 is listed. Table 3. Meaning of Hex Encoded Flags Flag Set in A Particular Band (microns) Resultant Value 100 60 25 12 of Encoded Flag (Bit 3) (Bit 2) (Bit 1) (Bit 0) xxxx = HEX = Decimal 0 0 0 0 0000 = 0 = 0 0 0 0 1 0001 = 1 = 1 0 0 1 0 0010 = 2 = 2 0 0 1 1 0011 = 3 = 3 0 1 0 0 0100 = 4 = 4 0 1 0 1 0101 = 5 = 5 0 1 1 0 0110 = 6 = 6 0 1 1 1 0111 = 7 = 7 1 0 0 0 1000 = 8 = 8 1 0 0 1 1001 = 9 = 9 1 0 1 0 1010 = A = 10 1 0 1 1 1011 = B = 11 1 1 0 0 1100 = C = 12 1 1 0 1 1101 = D = 13 1 1 1 0 1110 = E = 14 1 1 1 1 1111 = F = 15
Table 5. 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 = 2 Field2 and Field3 are V mag [decimag] at max,min = 3 Field2 and Field3 are photographic mag [decimag] at max,min = 4 Field2 and Field3 are estimated V mag [decimag] at max,min = 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 Type Blank Sky 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(0) [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 [1.0E-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 Center 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 [millimag] 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) [degrees K] ------------------------------------------------------------------------------ 23 OSU Type Blank Field1 999 Field2 999 Field3 Diameter [arcsec] ------------------------------------------------------------------------------ 24 IRC Type C if 2.2 micron sources are possibly confused, w/good pos. blank otherwise Field1 Right ascension difference (IRC-IRAS) [deciseconds of time] Field2 Declination difference (IRC-IRAS) [seconds of arc] Field3 0 ------------------------------------------------------------------------------ 25 DDO Type Blank Field1 999 Field2 999 Field3 0 ------------------------------------------------------------------------------ 26 Arp Type Blank Field1 999 Field2 999 Field 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- 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) 999 otherwise Field2 999 Field3 0 ------------------------------------------------------------------------------ 32 IRAS Small Type Blank Scale Structure Field1 Hex coded bands Field2 Blank Field3 Blank ------------------------------------------------------------------------------ 39 OSU Radio Type Blank Field1 Frequency Field2 Flux (deci Jy) 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 (mJy) Field3 Second SSC flux ------------------------------------------------------------------------------ Catalog numbers 33-38 are reserved for internal use. ** Source name and type fields were combined to hold spectral type and class. VV Catalog Flags (Catalog 31) FIELD1 Explanation 10 VV 10 has the same coordinates as VV 29 in the VV Atlas. The UGC was used to confirm that the coordinate is correct for VV 29 and erroneous for VV 10. The UGC position for VV 10 = UGC 10814 was adopted. 11 The VV position is substantially different (>400") 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'). |