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FITS Headers

DIRBE_BAND1A_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 = 'B1A_FSM '           / Faint Source Model (FSM) for Band 1A           
VERSION = 'Pass 3B '           / Version of Data Reduction Software             
WAVE1   = '1.25 microns'       / nominal wavelength of Band 1                   
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): 1.25 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 1.25 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_1               
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_1              
TUNIT3  = 'MJy/sr  '           /                                                
TFORM3  = '1E      '           /                                                
COMMENT   --------------------------------------------------------------------  
END                                                                             

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