ABS: an Analytical method of Blind Separation of CMB from foregrounds

TL;DR

The ABS method provides a blind, analytical approach to extract CMB B-mode polarization from foregrounds without relying on foreground models, applicable to various CMB measurements and other astrophysical signals.

Contribution

It introduces a novel, assumption-free analytical technique for separating CMB signals from foregrounds using cross bandpower data.

Findings

Successfully extracts CMB B-mode bandpower across various foregrounds.

Demonstrates numerical stability and broad applicability to different CMB components.

Works without multiple parameter fitting or foreground assumptions.

Abstract

Extracting CMB B-mode polarization from complicated foregrounds is a challenging task in searching for inflationary gravitational waves. We propose the ABS method as a blind and analytical solution to this problem. It applies to the measured cross bandpower between different frequency bands and obtains the CMB B-mode bandpower analytically. It does not rely on assumptions of foregrounds and does not require multiple parameter fitting. Testing against a variety of foregrounds, survey frequency configurations and instrument noise, we verify its applicability and numerical stability. The ABS method also applies to CMB temperature, E-mode polarization, the thermal Sunyaev Zel'dovich effect, spectral distortion, and even significantly different problems such as cosmic magnification.