DR. SOUMEN BASAK

Cosmic Microwave Background (CMB), the relic radiation left over from the Big Bang, provides the earliest possible image of the Universe, and encoded within this image are signatures of the fundamental parameters of cosmology. We introduce a novel model-independent method, named Needlet ILC (or NILC for short), to estimate CMB map and angular power spectrum from multi-frequency observations of the sky. This method is an implementation of an Internal Linear Combination (ILC) of the sky maps with minimum error variance on a frame of spherical wavelets called needlets, allowing localized filtering in both pixel space and harmonic space. NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has recently ¿nished a 9-year mission to map the sky in five frequency bands. The application of NILC to WMAP 9-year data will be presented in this talk.