DR. NIDHI PANT

Measuring non-vanishing BipoSH spectra forms the basic criteria behind searches for deviation from statistical isotropy (SI) in CMB maps. Masking and non-circular beam are among the several possible sources of SI violation. The full sky CMB is masked to remove the foreground emissions which leads to coupling among different multipoles and correlates even the uncorrelated spherical harmonic coefficients of CMB map. Similarly, masking couples an underlying SI violating signal (if any) BipoSH modes with mask BipoSH modes making it difficult to estimate the signal back from data. Deviations from circularity in instrumental beams can give rise to measurable SI violation in CMB data. We present semi-analytic methodology based on the BipoSH formalism to estimate signals of SI violation in presence of mask and non-circular beam with an arbitrary scan strategy. We demonstrate this method to estimate Doppler boost signal, a known SI violation signal in CMB measurements.