Knowra Intracluster medium Intracluster medium The intracluster medium is hot, diffuse plasma occupying the space between galaxies in a galaxy cluster. It emits X-rays and contains most of the cluster’s ordinary matter.
Bremsstrahlung : Electromagnetic radiation produced when charged particles are deflected by other charged particles. Deflected electrons emit much of the intracluster medium’s X-ray radiation.
Galaxy cluster : A gravitationally bound system containing many galaxies, hot gas, and dark matter. The intracluster medium is the diffuse baryonic component of this larger structure.
X-ray astronomy : The study of celestial objects through their X-ray emission. The medium’s thermal X-rays make clusters among the brightest extended sources in this band.
Hierarchical structure formation : The growth of cosmic structure through the merger and accretion of smaller systems. Cluster assembly builds up the hot medium through accretion and mergers.
Circumgalactic medium : The gas surrounding an individual galaxy, extending beyond its visible disk or stellar body. It is associated with individual galaxies, unlike the cluster-wide plasma between them.
Hydrostatic equilibrium : A state in which pressure gradients balance gravity in a stationary fluid. This balance lets X-ray observations estimate the cluster’s gravitational mass.
Baryon : A particle made of three quarks, including protons and neutrons. The medium consists chiefly of ordinary matter ultimately counted among the cluster’s baryons.
X-ray spectroscopy : The analysis of an X-ray spectrum to identify emission lines and physical conditions. Line strengths and shapes reveal the medium’s temperature, composition, and motions.
Cosmic web : The large-scale network of filaments, sheets, and voids formed by matter in the universe. Clusters accrete gas from surrounding filaments of this network.
Intergalactic medium : The diffuse gas occupying space between galaxies outside, and sometimes within, larger structures. The term covers a broader range of environments and conditions than cluster gas.
Show all 26