FITS Headers
wmap_composite_mask_yr1_v1.fits
Primary Header
SIMPLE = T / file does conform to FITS standard BITPIX = 8 / 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 is defined in 'Astronomy COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H DATE = '2003-07-30T00:00:00' /file creation date (YYYY-MM-DDThh:mm:ss UT) OBJECT = 'ALL-SKY ' / Portion of sky given COMMENT This file defines the sky pixels excluded by the WMAP intensity masks COMMENT Kp0, Kp2, Kp4, Kp12, the map-making (data processing) mask, and the COMMENT point source mask. If a pixel is excluded by a mask, then a unique COMMENT bit value is set. Bit values are set as follows: COMMENT bit0 not used. COMMENT bit1 set if excluded by Kp0; bit value = 2 COMMENT bit2 set if excluded by Kp2; bit value = 4 COMMENT bit3 set if excluded by Kp4; bit value = 8 COMMENT bit4 set if excluded by Kp12; bit value = 16 COMMENT bit5 set if excluded by processing mask; bit value = 32 COMMENT bit6 set if excluded by source mask; bit value = 64 COMMENT COMMENT The exclusion zone corresponding to a particular mask may be COMMENT reconstructed by performing a logical AND of the N_obs field (treated COMMENT as a byte variable) and the bit value set for that mask. For example, COMMENT point source exclusion zones may be obtained using COMMENT src = (BYTE(N_obs) AND 64)/64. To combine e.g. the Kp2 cut with the COMMENT point source cuts, first reconstruct the individual masks using the COMMENT logical AND described above, then perform a logical OR of the two in COMMENT order to obtain a composite exclusion map. Note that these COMMENT exclusion zone masks set an excluded pixel's value to 1 COMMENT whereas the convention used for the intensity masks products is to set COMMENT excluded pixels to 0. COMMENT COMMENT See the WMAP Explanatory Supplement for further details. REFERENC= 'WMAP Explanatory Supplement: http://lambda.gsfc.nasa.gov/ VERSION = 'PASS 1 ' / Internal MAP Version RESOLUTN= 9 / Resolution index SKYCOORD= 'Galactic' / Coordinate system PIXTYPE = 'HEALPIX ' / Pixel algorithm ORDERING= 'NESTED ' / Ordering scheme NSIDE = 512 / Resolution parameter NPIX = 3145728 / # of pixels FIRSTPIX= 0 / First pixel (0 based) LASTPIX = 3145727 / Last pixel (0 based) END
Archive Map Table
XTENSION= 'BINTABLE' /binary table extension BITPIX = 8 /8-bit bytes NAXIS = 2 /2-dimensional binary table NAXIS1 = 8 /width of table in bytes NAXIS2 = 3145728 /number of rows in table PCOUNT = 0 /size of special data area GCOUNT = 1 /one data group (required keyword) TFIELDS = 2 /number of fields in each row TTYPE1 = 'TEMPERATURE' /label for field 1 TFORM1 = '1E ' /data format of field: 4-byte REAL TUNIT1 = 'mK, thermodynamic' /physical unit of field TTYPE2 = 'N_OBS ' /label for field 2 TFORM2 = '1E ' /data format of field: 4-byte REAL TUNIT2 = 'counts ' /physical unit of field EXTNAME = 'Archive Map Table' /name of this binary table extension DATE = '2003-07-30T00:00:00' /Table creation date PIXTYPE = 'HEALPIX ' /Pixel algorithm ORDERING= 'NESTED ' /Ordering scheme NSIDE = 512 /Resolution parameter FIRSTPIX= 0 /First pixel (0 based) LASTPIX = 3145727 /Last pixel (0 based) COMMENT The TEMPERATURE field is set to 0 for all pixels. COMMENT N_obs defines masks. END
