Collapse, connectivity, and galaxy populations in supercluster cocoons: the case of A2142

TL;DR

This study examines the structure, dynamics, and galaxy populations of the A2142 supercluster and its surrounding cocoon, revealing a collapsing core and the distribution of old stellar populations across different environments.

Contribution

It provides a detailed analysis of the properties and connectivity of the A2142 supercluster and its cocoon at redshift 0.09, highlighting the collapsing state and galaxy distribution.

Findings

Supercluster core is collapsing.

Long filaments are detached from the supercluster.

Old stellar populations are present in various environments.

Abstract

The largest galaxy systems in the cosmic web are superclusters, overdensity regions of galaxies, groups, clusters, and filaments. Low-density regions around superclusters are called basins of attraction or cocoons. In my talk I discuss the properties of galaxies, groups, and filaments in the A2142 supercluster and its cocoon at redshift $z \approx 0.09$. Cocoon boundaries are determined by the lowest density regions around the supercluster. We analyse the structure, dynamical state, connectivity, and galaxy content of the supercluster, and its high density core with the cluster A2142. We show that the main body of the supercluster is collapsing, and long filaments which surround the supercluster are detached from it. Galaxies with very old stellar populations lie not only in the central parts of clusters and groups in the supercluster, but also in the poorest groups in the cocoon.