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healpixwindow
This IDL facility provides the window function in l associated with the
Healpix pixel of resolution Nside.
Location in HEALPix directory tree:
src/idl/misc/healpixwindow.pro
FORMAT IDL>
wpix=HEALPIXWINDOW (Nside [, Dim, Directory])
QUALIFIERS
-
Nside
- resolution parameter
-
Wpix
- the pixel window function, computed for the multipoles l in {0,...,4Nside}
-
Dim
- scalar integer, optional.
If absent or set to 0 or 1,
the output has size (4 Nside+1) and is the temperature
window function;
if set to  Dim  ,
the output has size (4 Nside+1,Dim)
and contains in that order :
the TEMPERATURE window function,
the GRAD/ELECTRIC polarization one
the CURL/MAGNETIC polarization one
the TEMPERATURE*GRAD one.
-
Directory
- directory in which the precomputed pixel window file is looked for.
default:$HEALPIX/data/
DESCRIPTION
healpixwindow computes the l space window function due to the finite size of the
HEALPix pixels. The typical size of a pixel (square root of its uniform surface
area) is
 arcmin.
If a unpixelised sky has a power spectrum C(l), the same
sky pixelised with a resolution parameter Nside
will have the power spectrum
 where W(l) is given by healpixwindow (Nside). The polarized
pixel window function is also provided (when Dim > 1).
This routine reads some FITS files located in the subdirectory data/ of the
HEALPix distribution, unless the keyword Directory is set otherwise.
RELATED ROUTINESThis section lists the routines related to healpixwindow
-
idl
- version 6.1 or more is necessary to run healpixwindow
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gaussbeam
- computes the l space window function associated with
a gaussian beam
-
synfast
- f90 code to generate CMB maps of given power spectrum at a
given resolution (=pixel size)
-
anafast
- f90 code to compute the power spectrum of a HEALPix sky map
EXAMPLE:
wpix contains the window function in {0,...,1024} of the HEALPix pixel with resolution
parameter 256 (pixel size of 13.7 arcmin)
Eric Hivon
2010-06-18
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