FITS Headers
DIRBE_BAND2A_FSM.FITS
Primary Header
SIMPLE = T / file does conform to FITS standard BITPIX = 32 / number of bits per data pixel NAXIS = 0 / number of data axes EXTEND = T / FITS dataset may contain extensions COMMENT FITS (Flexible Image Transport System) format defined in Astronomy and COMMENT Astrophysics Supplement Series v44/p363, v44/p371, v73/p359, v73/p365. COMMENT Contact the NASA Science Office of Standards and Technology for the COMMENT FITS Definition document #100 and other FITS information. DATE = '04/08/97' / FITS file creation date (dd/mm/yy) DATE-MAP= '10/01/96' / Date of original file creation (dd/mm/yy) ORIGIN = 'CDAC ' / Cosmology Data Analysis Center TELESCOP= 'COBE ' / Cosmic Background Explorer satellite INSTRUME= 'DIRBE ' / COBE instrument [DIRBE, DMR, FIRAS] OBJECT = 'ALL-SKY ' / part of sky given [e.g., ALL-SKY, WEEKLY-SKY, COMMENT / DAILY-SKY, GAL-SLICE, FACE ...] EQUINOX = 2000.0 / equinox of coords in following tables REFERENC= 'COBE/DIRBE Explanatory Supplement,' / REFERENC= 'ed. M.G. Hauser, T. Kelsall, D. Leisawitz, and J. Weiland,' / REFERENC= 'COBE Ref. Pub. No. 97-A (Greenbelt,MD: NASA/GSFC),' / REFERENC= 'available in electronic form from the NSSDC.' / COMMENT COMMENT COBE specific keywords PIXRESOL= 9 / Quad tree pixel resolution [6, 9] COMMENT COMMENT DIRBE specific keywords PRODUCT = 'B2A_FSM ' / Faint Source Model (FSM) for Band 2A VERSION = 'Pass 3B ' / Version of Data Reduction Software WAVE2 = '2.2 microns' / nominal wavelength of Band 2 FSMMODEL= 'FD6 ' / Version of DIRBE FSM Model COMMENT COMMENT END
Extension Header 2
XTENSION= 'BINTABLE' / Extension type is Binary Table BITPIX = 8 / Binary data NAXIS = 2 / Data are in a table NAXIS1 = 12 / Number of 8 bit bytes in each row NAXIS2 = 393216 / Number of rows PCOUNT = 0 / Number of bytes of data following table GCOUNT = 1 / Group count (always 1 for bintable extensions) TFIELDS = 3 / Number of fields (columns) in the table COMMENT ------------------------------------------------------------------- COMMENT ******************************************************************* COMMENT ------ DIRBE Faint Source Model (FSM): 2.2 microns ------ COMMENT COMMENT The Faint Source Model is designed to represent the smooth COMMENT collective emission from stellar sources in the Milky Way COMMENT which are unresolved by DIRBE. It is based on the COMMENT statistical model developed by Wainscoat et al. COMMENT (1992, ApJS, 83, 111), with some DIRBE-specific modifications. COMMENT The FSM is described in greater detail in the DIRBE COMMENT Explantory Supplement, Chapter 5. COMMENT COMMENT Since emission from stars is negligible compared to COMMENT emission from Galactic dust at longer wavelengths, the COMMENT FSM is computed only for the nominal DIRBE wavelengths of COMMENT 1.25, 2.2, 3.5, 4.9, 12 and 25 microns. There are six COMMENT FSM files, one for each wavelength. COMMENT COMMENT The FSM is a statistical model based on source counts, and COMMENT thus cannot accurately represent the brightest point sources, COMMENT which are unevenly distributed across the sky. Therefore, COMMENT the FSM brightness integral is limited to those sources COMMENT FAINTER than a wavelength-dependent brightness cutoff. COMMENT These brightness thresholds are 15, 15, 15, 15, 85 and 110 Jy COMMENT for sources at 1.25, 2.2, 3.5, 4.9, 12 and 25 microns, COMMENT respectively. COMMENT COMMENT USER BEWARE: The FSM data product was not designed for COMMENT general use; the product was generated to preserve and COMMENT make public a record of the FSM used by the DIRBE team COMMENT to remove Galactic foreground emission. The brightness COMMENT integration limits were specifically chosen to maintain COMMENT consistency with procedures used in the DIRBE science COMMENT analysis pipeline. The FSM is of limited utility for COMMENT other purposes. COMMENT COMMENT ******************************************************************* COMMENT -------------------------------------------------------------------- COMMENT ==================================================================== COMMENT Coordinate Information : COMMENT ==================================================================== COMMENT -------------------------------------------------------------------- COMMENT DIRBE Pixel number (resolution 9) TTYPE1 = 'Pixel_no' / pipeline fieldname = Pixel_no TUNIT1 = ' ' / TFORM1 = '1J ' / COMMENT -------------------------------------------------------------------- COMMENT ==================================================================== COMMENT Model Brightness Information: COMMENT ==================================================================== COMMENT -------------------------------------------------------------------- COMMENT Model Brightness at 2.2 microns COMMENT The computed model brightness COMMENT is given as a spectral intensity, I(nu) in MJy/sr, and COMMENT is quoted at the nominal wavelength COMMENT for a source with nu*I(nu) = constant -- i.e., COMMENT a color correction is required if the source COMMENT spectrum differs from nu*I(nu) = constant. COMMENT TTYPE2 = 'Photomet' / pipeline fieldname = gfs_model_2 TUNIT2 = 'MJy/sr ' / TFORM2 = '1E ' / COMMENT -------------------------------------------------------------------- COMMENT Uncertainty associated with the Model Brightness COMMENT The 1-sigma statistical uncertainty in the modeled COMMENT intensity, assuming Poisson counting statistics. TTYPE3 = 'StdDev ' / pipeline fieldname = gfs_sigma_2 TUNIT3 = 'MJy/sr ' / TFORM3 = '1E ' / COMMENT -------------------------------------------------------------------- END
