Evidence of Galaxy Cluster Motions with the Kinematic Sunyaev-Zel'dovich Effect

TL;DR

This paper provides the first strong observational evidence of galaxy cluster motions using the kinematic Sunyaev-Zel'dovich effect, linking microwave background distortions to cosmic structure growth.

Contribution

It introduces a novel measurement of galaxy cluster velocities via microwave background distortions, combining high-resolution sky maps with galaxy surveys.

Findings

Detected significant cluster motions with high confidence

Results align with standard cosmological model predictions

First direct measurement of cluster velocities using this method

Abstract

Using high-resolution microwave sky maps made by the Atacama Cosmology Telescope, we for the first time present strong evidence for motions of galaxy clusters and groups via microwave background temperature distortions due to the kinematic Sunyaev-Zel'dovich effect. Galaxy clusters are identified by their constituent luminous galaxies observed by the Baryon Oscillation Spectroscopic Survey, part of the Sloan Digital Sky Survey III. We measure the mean pairwise momentum of clusters, with a probability of the signal being due to random errors of 0.002, and the signal is consistent with the growth of cosmic structure in the standard model of cosmology.