Towards reconstruction of unlensed, intrinsic CMB power spectra from lensed map

TL;DR

This paper introduces a matrix inversion method to reconstruct the original, unlensed CMB power spectra from observed lensed data, aiding in the analysis of primordial signals.

Contribution

The authors develop a direct reconstruction technique for intrinsic CMB spectra from lensed observations, applicable to both flat and full sky analyses.

Findings

Successfully calibrated against CAMB and WMAP data.

Demonstrated the method's effectiveness on WMAP 9-year data.

Potential to isolate intrinsic B-mode polarization by removing lensing effects.

Abstract

We propose a method to extract the unlensed, intrinsic CMB temperature and polarization power spectra from the observed (i.e., lensed) spectra. Using a matrix inversion technique, we demonstrate how one can reconstruct the intrinsic CMB power spectra directly from lensed data for both flat sky and full sky analyses. The delensed spectra obtained by the technique are calibrated against the Code for Anisotropies in the Microwave Background (CAMB) using WMAP 7-year best-fit data and applied to WMAP 9-year unbinned data as well. In principle, our methodology may help in subtracting out the E-mode lensing contribution in order to obtain the intrinsic B-mode power.