This routine modifies scalar (and tensor) alm by multiplying them by a beam window
function described by a FWHM (in the case of a gaussian beam) or read from an external
file (in the more general case of a circular beam)
. It can also be used to
multiply the alm by an arbitray function of l.
Location in HEALPix directory tree:
nsmax, nlmax, nmmax, fwhm_arcmin, alm_TGC [, beam_file, window]
|name & dimensionality
resolution parameter of the map associated with the alm
considered. Currently has no effect on the routine.
||maximum l value for the alm.
||maximum m value for the alm.
||fwhm size of the gaussian beam in arcminutes.
||complex alm values
to be altered. The first index here runs from 1:1 for
temperature only, and 1:3 for polarisation. In the latter
case, 1=T, 2=E, 3=B.
||name of the file
containing the (non necessarily gaussian) window function
Bl of a circular beam. If present, it will override
the argument fwhm_arcmin.
||arbitrary window by which to multiply the
alm. If present, it overrides both fwhm_arcmin
and beam_file. If nlw < nlmax, the alm with
nlw+1,nlmax} are set to 0, and a warning is issued. If d<p the
window for temperature is replicated for polarisation.
call alter_alm(64, 128, 128, 1, 5.0, alm_TGC)
Alters scalar and tensor alm of a map with
by multiplying them by the beam window function of a
gaussian beam with FWHM = 5 arcmin.
MODULES & ROUTINES
This section lists the modules and routines used by alter_alm*.
- module, containing:
- routine to generate beam window function
- routine to generate pixel window function
This section lists the routines related to alter_alm*
- Routine to create alm coefficients.
- Routine to rotate alm
coefficients between 2 different arbitrary coordinate systems.
- Routines to analyze a HEALPix sky map into its alm
- Routines to synthetize a HEALPix sky map from its alm
- Routines to save a set of alm in a FITS file.