CMB and SZ effect separation with Constrained Internal Linear Combinations

TL;DR

This paper extends the Internal Linear Combination method to simultaneously separate and produce clean maps of the CMB and thermal SZ effect from multifrequency data, improving component separation accuracy.

Contribution

It introduces a Constrained ILC approach that isolates CMB and SZ signals with minimal contamination, validated on simulated Planck data.

Findings

Successful reconstruction of independent CMB and SZ maps from simulations

Enhanced separation accuracy over traditional ILC methods

Validated performance on Planck-like observational data

Abstract

The `Internal Linear Combination' (ILC) component separation method has been extensively used on the data of the WMAP space mission, to extract a single component, the CMB, from the WMAP multifrequency data. We extend the ILC approach for reconstructing millimeter astrophysical emissions beyond the CMB alone. In particular, we construct a Constrained ILC to extract clean maps of both the CMB or the thermal Sunyaev Zeldovich (SZ) effect, with vanishing contamination from the other. The performance of the Constrained ILC is tested on simulations of Planck mission observations, for which we successfully reconstruct independent estimates of the CMB and of the thermal SZ.