healpy.rotator.Rotator.rotate_map_alms

Rotator.rotate_map_alms(m, use_pixel_weights=True, lmax=None, mmax=None, datapath=None, verbose=None)

Rotate a HEALPix map to a new reference frame in spherical harmonics space.

This is generally the best strategy to rotate/change reference frame of maps. If the input map is band-limited, i.e. it can be represented exactly by a spherical harmonics transform under a specific lmax, the map rotation will be invertible.

Parameters:

mnp.ndarray

Input map, single array is considered I, array with 3 rows:[I,Q,U]

use_pixel_weightsbool, optional

If True, use pixel by pixel weighting in the map2alm step. Default: True.

lmaxint, optional

Maximum l for the spherical harmonics transform. Default: 3*nside-1.

mmaxint, optional

Maximum m for the spherical harmonics transform. Default: lmax.

datapathstr or None, optional

If given, the directory where to find the pixel weights data.

verbosebool, optional

Deprecated, has no effect.

Returns:

m_rotatednp.ndarray

Map in the new reference frame