The correlation structure of dark matter halo properties

TL;DR

This study analyzes the relationships among nine dark matter halo properties, revealing that concentration is fundamental and most properties are correlated with it, while some like spin and environment are more independent.

Contribution

It provides a comprehensive correlation analysis of multiple halo properties, highlighting the central role of concentration and the independence of certain parameters.

Findings

Concentration is the most fundamental property.

Most parameters are strongly correlated with concentration.

Spin and environment are more independent from other properties.

Abstract

We investigate the correlation between nine different dark matter halo properties using a rank correlation analysis and a Principal Component Analysis for a sample of haloes spanning five orders of magnitude in mass. We consider mass and dimensionless measures of concentration, age, relaxedness, sphericity, triaxiality, substructure, spin, and environment, where the latter is defined in a way that makes it insensitive to mass. We find that concentration is the most fundamental property. Except for environment, all parameters are strongly correlated with concentration. Concentration, age, substructure, mass, sphericity and relaxedness can be considered a single family of parameters, albeit with substantial scatter. In contrast, spin, environment, and triaxiality are more independent, although spin does correlate strongly with substructure and both spin and triaxiality correlate substantially with concentration. Although mass sets the scale of a halo, all other properties are more sensitive to concentration.