Prospects for independent measurement of $\boldsymbol{\ell}$=1,2,3 CMB anisotropy multipoles using the anisotropic Sunyaev-Zel'dovich effect

Abstract

We investigate the prospects for observing a specific spectral distortion of the cosmic microwave background, which occurs due to the anisotropy of the radiation when it is scattered by hot plasma of galaxy clusters. Detection of this "anisotropic Sunyaev-Zel'dovich effect" will allow us to independently measure the anisotropy multipoles with $\ell=1,2,3$, separate the Sachs-Wolf effect from the integrated Sachs-Wolf effect (Rees-Sciama effect) and, to a certain extent, circumvent the 'cosmic variance' problem for low multipoles. We propose a modified Least Response Method for the components separation in the data processing and estimate the required sensitivity of the experiment for such observations. We test our approach on a simulated signal that is contaminated by various foregrounds with poorly defined spectral shapes, along with distortions of the relic blackbody spectrum caused by the Sunyaev-Zel'dovich effect and its relativistic corrections.