Properties of clumps and filaments around galaxy clusters

TL;DR

This study explores the properties of cosmic clumps and filaments around galaxy clusters using simulations, revealing how their thermodynamics relate to cluster mass and position, and suggesting observational strategies for studying diffuse baryons.

Contribution

The paper introduces new algorithms for identifying cosmic structures in simulations and analyzes their properties, providing insights into baryon thermodynamics around galaxy clusters.

Findings

Clump density and temperature are independent of cluster mass.

Filament temperature correlates positively with host cluster mass.

Clumps are hotter and more luminous near the cluster center.

Abstract

We report on the possibility of studying the proprieties of cosmic diffuse baryons by studying self-gravitating clumps and filaments connected to galaxy clusters. While filaments are challenging to detect with X-ray observations, the higher density of clumps makes them visible and a viable tracer to study the thermodynamical proprieties of baryons undergoing accretion along cosmic web filaments onto galaxy clusters. We developed new algorithms to identify these structures and applied them to a set of non-radiative cosmological simulations of galaxy clusters at high resolution. We find that in those simulated clusters, the density and temperature of clumps are independent of the mass of the cluster where they reside. We detected a positive correlation between the filament temperature and the host cluster mass. The density and temperature of clumps and filaments also tended to correlate. Both the temperature and density decrease moving outward. We observed that clumps are hotter, more massive, and more luminous if identified closer to the cluster center. Especially in the outermost cluster regions (~3*R500,c or beyond), X-ray observations might already have the potential to locate cosmic filaments based on the distribution of clumps and to allow one to study the thermodynamics of diffuse baryons before they are processed by the intracluster medium.