Clusters in the Disperse cosmic web

TL;DR

This paper investigates the relationship between galaxy clusters and cosmic web structures identified by the Disperse method, revealing how clusters associate with web nodes and filaments across different simulation parameters.

Contribution

It introduces a systematic approach to match galaxy clusters with Disperse cosmic web nodes, analyzing how these associations vary with web parameters and matching criteria.

Findings

Approximately 75% of clusters have Disperse node counterparts for certain smoothing scales.

Cluster-Disperse node pairs follow a mass-density relation within twice the smoothing length.

Clusters matched to Disperse nodes show enhanced subhalo counts and halo mass.

Abstract

Galaxy cluster mass halos ("clusters") in a dark matter simulation are matched to nodes in several different cosmic webs found using the Disperse cosmic web finder. The webs have different simulation smoothings and Disperse parameter choices; for each, 4 methods are considered for matching Disperse nodes to clusters. For most of the webs, Disperse nodes outnumber clusters, but not every cluster has a Disperse node match (and sometimes $>1$ cluster matches to the same Disperse node). The clusters frequently lacking a matching Disperse node have a different distribution of local shear trends and perhaps merger histories. It might be interesting to see in what other ways, e.g., observational properties, these clusters differ. For the webs with smoothing $\leq$ 2.5 $Mpc/h$, and all but the most restrictive matching criterion, $\sim$3/4 of the clusters always have a Disperse node counterpart. The nearest cluster to a given Disperse node and vice versa, within twice the smoothing length, obey a cluster mass-Disperse node density relation. Cluster pairs where both clusters match Disperse nodes can also be assigned the filaments between those nodes, but as the web and matching methods are varied, most such filaments do not remain. There is an enhancement of subhalo counts and halo mass between cluster pairs, averaging over cluster pairs assigned Disperse filaments increases the enhancement. The approach here also lends itself to comparing nodes across many cosmic web constructions, using the fixed underlying cluster distribution to make a correspondence.