The MSX Infrared Astrometric Catalog Version 4.2.1 Text Version of Documentation, 2/96 M. P. Egan & S. D. Price Phillips Lab/GPOB 1. Introduction This version of the MSX IR Astrometric Catalog is a truncated version of the documentation which exists for the convenience of the user and is primarily intended to allow quick access to the file formats and other information needed to access the information. The AJ paper contains the definitive information about the catalog itself. The MSX IR Astrometric Catalog, Version 4.2.1 was constructed from a number of visible astrometric catalogs, and contains position information accurate to the sub-arcsecond level. The FK5 (1988 Fricke Schwan & Lederle), FK5 Extension (1991 Fricke, Schwan & Corbin), Astrographic Catalog of Reference Stars (1991 Corbin & Urban), Position and Proper Motion Catalog (1988 Roeser & Bastian) and PPM South (1991 Bastian et al.) were the sources of position and magnitude information. The PPM and FK5 catalogs contain 1-D spectral type information, and this was supplemented where possible with 2-D MK spectral types. The ACRS and PPM quote photographic magnitudes. These were transformed to V magnitude using the spectral type and expected B-V color. Spatial coincidence and color-matching criteria (based on V-[12] color and spectral type) were used to identify IR counterparts of the astrometric stars. The IRAS Point Source, Faint Source, Faint Source Reject file, and Serendipitous Survey catalogs were used to supply IR observations, as was the Catalog of Infrared Observations (1993 Gezari et al.). The IR flux in each SPIRIT III band was estimated using the V magnitude, spectral type, and IR flux (if available) to determine a blackbody spectrum for the star, which was then convolved with the system spectral response of each SPIRIT III radiometer band. Stars which were brighter than 8th magnitude in band A were retained in the final MSX IR astrometric catalog. In MSXv4.2.1, there are 177860 stars, 61242 of which had IR counterparts. 2. File Formats The following tables list the format of each file. The catalog ID's referred to are: Astrometric Catalog ID ___________________________________________ FK5 F FK5 Extension f ACRS A PPM N PPM South S Infrared Catalog ID ___________________________________________ IRAS Point Source Catalog P IRAS Faint Source Catalog F Combined PSC/FSC data B IRAS Faint Source Reject Z IRAS Serendiptious Survey S Catalog of IR Observations C Table 1. Format of MSX4_2_1 __________________________________________________________________________ column format description __________________________________________________________________________ 1 a1 Original astrometric catalog ID 2:7 i6 astrometric catalog number 8 a1 IR catalog ID 9:21 a13 Name of star in IR catalog 22:23 i2 R.A. hours (J2000) 24:25 i2 R.A. minutes (J2000) 26:31 f6.3 R.A. seconds (J2000) 32 a1 sign of declination 33:34 i2 declination degrees (J2000) 35:36 i2 declination arcminutes (J2000) 37:41 f5.2 declination arcseconds (J2000) 42:47 f6.1 mean R.A. error*cos(dec), 0.001 seconds of time 48:52 f5.1 mean declination error, 0.01 seconds of arc 53:61 f9.3 proper motion in R.A., (J2000) s of time/Julian cy 62:70 f9.2 proper motion in dec., (J2000) sec of arc/Julian cy 71:76 f6.1 mean error of R.A. PM*cos(dec), 0.001 s of time/cy 77:82 f6.1 mean error of dec PM, 0.01 s of arc/cy 83:85 3a1 spectral type (e.g. G83 = G8 III; G80 = G8) 86:87 a2 IRAS LRS designation 88:92 f5.2 visual magnitude, V 93:101 e9.3 IRAS 12 micron flux (Jy) or wavelength of CIO obs. 102:110 e9.3 IRAS 25 micron flux (Jy) or flux (Jy) of CIO obs. 111:119 e9.3 IRAS 60 micron flux (Jy) or wavelength of CIO obs. 120:128 e9.3 IRAS 100 micron flux (Jy) or flux (Jy) of CIO obs. 129 i1 IRAS 12 micron flux quality flag, fqual(1) 130 i1 IRAS 25 micron flux quality flag, fqual(2) 131 i1 IRAS 60 micron flux quality flag, fqual(3) 132 i1 IRAS 100 micron flux quality flag, fqual(4) 133:141 e9.3 SPIRIT III Band A flux density estimate (Jy) 142:150 e9.3 SPIRIT III Band B1 flux density estimate (Jy) 151:159 e9.3 SPIRIT III Band B2 flux density estimate (Jy) 160:168 e9.3 SPIRIT III Band C flux density estimate (Jy) 169:177 e9.3 SPIRIT III Band D flux density estimate (Jy) 178:186 e9.3 SPIRIT III Band E flux density estimate (Jy) 187:195 e9.3 Estimated IRAS 12 micron flux (Jy) __________________________________________________________________________