A catalogue of merging clusters of galaxies: cluster partners, merging subclusters, and post-collision clusters

TL;DR

This paper presents a large catalog of merging galaxy clusters, identifying pre-mergers, subclusters, and post-collision systems using optical and X-ray data, providing valuable resources for studying cosmic structure formation.

Contribution

The study introduces a comprehensive catalog of merging galaxy clusters, including new methods for identifying subclusters and post-collision mergers from optical survey data.

Findings

Identified 39,382 cluster partners within specific velocity and separation criteria.

Detected 7,845 clusters with merging subclusters using a two-component profile model.

Found 3,446 post-collision mergers, including two new bullet-like clusters.

Abstract

Clusters of galaxies are merging during the formation of large-scale structures in the Universe. Based on optical survey data, we identify a large sample of pre-mergers of galaxy clusters and merging subclusters in rich clusters. We find 39,382 partners within a velocity difference of 1500 km/s and a projected separation of 5r_{500} around 33,126 main clusters, where r_{500} is the radius of the main cluster. Based on the galaxy distribution inside rich clusters with more than 30 member galaxy candidates, we identify subclusters by modeling the smoothed optical distribution with a two-component profile, and a coupling factor is obtained for merging subclusters in 7845 clusters. In addition, we find 3446 post-collision mergers according to the deviations of brightest cluster galaxies from other member galaxies, most of which have been partially validated by using the Chandra and XMM-Newton X-ray images. Two new bullet-like clusters have been identified by using the optical and X-ray images. The large samples of merging clusters of galaxies presented here are important databases for studying the hierarchical structure formation, cluster evolution, and the physics of intergalactic medium.