Shapes and Probabilities of Galaxy Clusters II: Comparisons with observations

TL;DR

This study compares observed galaxy cluster energies from SDSS data with theoretical predictions, revealing correlations between velocity and spatial anisotropies and confirming the theory's accuracy across various scales.

Contribution

It provides the first detailed comparison of galaxy cluster energy distributions with theoretical models, including anisotropy measures.

Findings

Velocity anisotropy correlates with spatial anisotropy.

Energy distribution matches theoretical predictions across scales.

The approach estimates cluster velocity and spatial anisotropies.

Abstract

We identify low redshift clusters and groups in the Sloan Digital Sky Survey (SDSS) and estimate their kinetic and correlation potential energies. We compare the distribution of these energies to the predictions by Yang and Saslaw (2012) and in the process estimate a measure of an average 3-dimensional velocity and spatial anisotropy of a sample of clusters. We find that the inferred velocity anisotropy is correlated with the inferred spatial anisotropy. We also find that the general shape of the energy distribution agrees with theory over a wide range of scales from small groups to superclusters once the uncertainties and fluctuations in the estimated energies are included.