We introduce NeedATool (Needlet Analysis Tool), a software for data analysis
based on needlets, a wavelet rendition which is powerful for the analysis of
fields defined on a sphere. Needlets have been applied successfully to the
treatment of astrophysical and cosmological observations, and in particular to
the analysis of cosmic microwave background (CMB) data. Usually, such analyses
are performed in real space as well as in its dual domain, the harmonic one.
Both spaces have advantages and disadvantages: for example, in pixel space it
is easier to deal with partial sky coverage and experimental noise; in harmonic
domain, beam treatment and comparison with theoretical predictions are more
effective. During the last decade, however, wavelets have emerged as a useful
tool for CMB data analysis, since they allow to combine most of the advantages
of the two spaces, one of the main reasons being their sharp localisation. In
this paper, we outline the analytical properties of needlets and discuss the
main features of the numerical code, which should be a valuable addition to the
CMB analyst's toolbox.Comment: software available at:
http://www.fisica.uniroma2.it/~pietrobon/dp_files/dp_NeedATool_download.htm
