Galaxy clusters form from the infall of dark and baryonic matter at the intersection of cosmic filaments. Most of the baryons are in the form of a hot, magnetized, intracluster plasma detected through its X-ray thermal bremsstrahlung emission. This plasma is tightly coupled to a second, cosmic ray plasma, detected through its synchrotron radio emission. Together, the properties of these plasmas encode the history of the cluster's formation and provide a snapshot of the ongoing cluster evolution. This article provides an overview for the more general astrophysical and space plasma community of the dynamical processes revealed by the diffuse plasma emissions.
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Proprieties of clumps and filaments around galaxy clusters
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⋅ R 500, 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.
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- Award ID(s):
- 1714205
- NSF-PAR ID:
- 10326086
- Date Published:
- Journal Name:
- Astronomy & Astrophysics
- Volume:
- 653
- ISSN:
- 0004-6361
- Page Range / eLocation ID:
- A171
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1051/0004-6361/202140471
