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gaussbeam
This IDL facility provides the window function in l space for a
gaussian axisymmetric beam of given FWHM.
Location in HEALPix directory tree:
src/idl/misc/gaussbeam.pro
FORMAT IDL>
beam=GAUSSBEAM (Fwhm, Lmax [, Dim])
QUALIFIERS
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Fwhm
- Full Width Half Maximum of the gaussian beam, in arcmin (scalar real)
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Lmax
- the window function is computed for the multipoles l in {0,...,Lmax}
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Dim
- scalar integer, optional.
If absent or set to 0 or 1,
the output has size (Lmax+1) and is the temperature beam;
if set to Dim ,
the output has size (Lmax+1,Dim)
and contains in that order :
the TEMPERATURE beam,
the GRAD/ELECTRIC polarization beam
the CURL/MAGNETIC polarization beam
the TEMPERATURE*GRAD beam
DESCRIPTION
gaussbeam computes the l space window function of a gaussian beam of FWHM
Fwhm. For a sky of underlying power spectrum C(l) observed with beam of
given FWHM, the measured power spectrum will be
where B(l) is given by gaussbeam(Fwhm,Lmax). The
polarization beam is also provided (when Dim > 1) assuming a perfectly
co-polarized beam (eg, Challinor et al 2000, astro-ph/0008228)
RELATED ROUTINESThis section lists the routines related to gaussbeam
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idl
- version 6.1 or more is necessary to run gaussbeam
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healpixwindow
- computes the tex2html_wrap_inline$l$ space window function associated with
a HEALPix pixel size
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synfast
- f90 code to generate CMB maps of given power spectrum convolved with a gaussian beam
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smoothing
- f90 code to smooth existing HEALPix maps with a gaussian beam
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anafast
- f90 code to compute the power spectrum of a HEALPix sky map
EXAMPLE:
beam contains the window function in {0,...,1200} of a gaussian beam of fwhm 5 arcmin
Eric Hivon
2010-06-18
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