The effect of cluster magnetic field on the Sunyaev-Zel'dovich power spectrum

Abstract

Precision measurements of the Sunyaev-Zel'dovich (SZ) effect in upcoming blank sky surveys require theoretical understanding of all physical processes with ≳ 10 per cent effects on the SZ power spectrum. We show that the observed cluster magnetic field could reduce the SZ power spectrum by ∼20 per cent at l ∼ 4000, where the SZ power spectrum will be precisely measured by the Sunyaev-Zel'dovich array (SZA) and the Atacama Cosmology Telescope (ACT). At smaller scale, this effect is larger and could reach a factor of several. Such an effect must be considered for an unbiased interpretation of the SZ data. Although the magnetic effect on the SZ power spectrum is very similar to that of radiative cooling, it is measurable by multiband cosmic microwave background polarization measurement.