A Blind Estimation of the Power Spectrum of Cmb Anisotropy from Wmap

The angular power spectrum of Cosmic Microwave Background (CMB) radiation has proved to be an excellent observation to measure different cosmological parameters. In order to extract cosmological parameters precisely we need to remove foreground contamination as well as detector noise bias. In this paper we present a framework to extract CMB angular power spectrum from the multi-frequency observations of WMAP using a model-independent method. The primary product of WMAP are the observations of CMB in 10 independent difference assemblies (DA) that have uncorrelated noise. Our method utilizes maximum information available within WMAP data by linearly combining all the DA maps to remove foregrounds and estimating the power spectrum from cross power spectra of clean maps with independent noise. We compute 24 cross power spectra which are the basis of the final power spectrum. The binned average power matches with WMAP team’s published power spectrum roughly within the 1σ error bars. This demonstrates that the final CMB angular spectrum can be estimated from a self contained analysis of the WMAP data without recourse to extraneous observational inputs such as that which go into making foreground templates and model point source spectrum. Subject headings: cosmic microwave background cosmology: observations