Kinetic Sunyaev--Zel'dovich effect in rotating galaxy clusters from MUSIC simulations

TL;DR

This study uses high-resolution simulations to analyze the kinetic Sunyaev--Zel'dovich effect in galaxy clusters, demonstrating the potential to reconstruct gas rotation profiles and measure bulk velocities accurately.

Contribution

It introduces a method to recover gas rotational velocity profiles from SZ maps using a theoretical model, validated on simulated galaxy clusters.

Findings

Successfully recovered rotational velocity profile parameters within two standard deviations.

The rotational SZ signal amplitude is about 23% of the bulk motion signal.

Bulk velocity measurements from the SZ maps are consistent with simulation true values.

Abstract

The masses of galaxy clusters are a key tool to constrain cosmology through the physics of large-scale structure formation and accretion. Mass estimates based on X-ray and Sunyaev--Zel'dovich measurements have been found to be affected by the contribution of non-thermal pressure components, due e.g. to kinetic gas energy. The characterization of possible ordered motions (e.g. rotation) of the intra-cluster medium could be important to recover cluster masses accurately. We update the study of gas rotation in clusters through the maps of the kinetic Sunyaev--Zel'dovich effect, using a large sample of massive synthetic galaxy clusters ($ M_{vir} > 5\times 10^{14} h^{-1}$M$_\odot$ at $z~=~0 $) from MUSIC high-resolution simulations. We select few relaxed objects showing peculiar rotational features, as outlined in a companion work. To verify whether it is possible to reconstruct the expected radial profile of the rotational velocity, we fit the maps to a theoretical model accounting for a specific rotational law, referred as the vp2b model. We find that our procedure allows to recover the parameters describing the gas rotational velocity profile within two standard deviations, both with and without accounting for the bulk velocity of the cluster. The amplitude of the temperature distortion produced by the rotation is consistent with theoretical estimates found in the literature, and it is of the order of 23 per cent of the maximum signal produced by the cluster bulk motion. We also recover the bulk velocity projected on the line of sight consistently with the simulation true value.