CMB anisotropy power spectrum using linear combinations of WMAP maps

TL;DR

This paper presents a novel, model-independent method to accurately estimate the CMB angular power spectrum directly from WMAP data, effectively removing foregrounds and noise without relying on external templates.

Contribution

It introduces a new self-contained approach for estimating the CMB power spectrum from WMAP data, demonstrating improved reliability and precision over previous template-based methods.

Findings

Successfully applied to WMAP 1-year and 3-year data sets.

Identified and analyzed biases in the power spectrum estimation.

Achieved reliable, model-independent estimates of the CMB angular power spectrum.

Abstract

In recent years the goal of estimating different cosmological parameters precisely has set new challenges in the effort to accurately measure the angular power spectrum of CMB. This has required removal of foreground contamination as well as detector noise bias with reliability and precision. Recently, a novel {\em model-independent} method for the estimation of CMB angular power spectrum solely from multi-frequency observations has been proposed and implemented on the first year WMAP data by Saha et al. 2006. All previous estimates of power spectrum of CMB are based upon foreground templates using data sets from different experiments. However our methodology demonstrates that {\em CMB angular spectrum can be reliably estimated with precision from a self contained analysis of the WMAP data}. In this work we provide a detailed description of this method. We also study and identify the biases present in our power spectrum estimate. We apply our methodoly to extract the power spectrum from the WMAP 1 year and 3 year data.