Bulk motion measurements in clusters of galaxies with ATHENA-like missions

TL;DR

This paper demonstrates the feasibility of using high-resolution X-ray spectroscopy with ATHENA-like missions to detect and map bulk motions in galaxy clusters, providing new insights into cluster formation and mass estimation.

Contribution

It introduces a method to measure and map gas bulk motions in galaxy clusters using Doppler shifts of X-ray emission lines with future ATHENA-like missions.

Findings

Feasible detection of bulk motions via Doppler shifts

Potential for improved cluster formation diagnostics

Enhanced accuracy in X-ray mass estimates

Abstract

The hierarchical formation of clusters of galaxies by accretion of material releases gravitational energy which dissipates into the intracluster gas. The process heats the material and generates gas turbulence and bulk motions and thus kinetic pressure. Mapping the velocity fields of the moving subunits would enable a new diagnostics tool for cluster formation studies and unbiased X-ray mass estimates. The required spatially resolved high resolution spectroscopy is not currently available. I demonstrate here the feasibility of detecting and mapping the velocities of the bulk motions using the Doppler shift of the Fe XXV K alpha line with the proposed ATHENA satellite.