Dipole leakage and low CMB multipoles
  A number of studies of WMAP-7 have highlighted that the power at the low
multipoles in CMB power spectrum are lower than their theoretically predicted
values. Angular correlation between the orientations of these low multipoles
have also been discovered. While these observations may have cosmological
ramification, it is important to investigate possible observational artifacts
that can mimic them. The CMB dipole which is almost 550 times higher than the
quadrupole can get leaked to the higher multipoles due to the non-circular beam
of the CMB experiment. In this paper an analytical method has been developed
and simulations are carried out to study the effect of the non-circular beam on
power leakage from the dipole. It has been shown that the small, but
non-negligible power from the dipole can get transferred to the quadrupole and
the higher multipoles due to the non-circular beam. Simulations have also been
carried out for Planck scan strategy and comparative results between WMAP and
Planck have been presented in the paper.
