1997/10/22 by S. Ettori, A. C. Fabian · 1 citation
Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Atomic physics #Cluster (spacecraft) #Coulomb #Electron #Electron temperature #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Intracluster medium #Nuclear physics #Physics #Quantum mechanics #Stellar, planetary, and galactic studies #Temperature gradient #Virial theorem #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.1998.01253.x
published as MNRAS, 293, L33 (1998) · 4 pages, accepted as a Letter in the MNRAS
arxiv created 1997/10/22 · openalex publication_date 1998/01/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In this paper we discuss the effect of Coulomb collisions on the temperature profiles of the intracluster medium in clusters of galaxies, motivated by recent reports of negative temperature gradients in some clusters by Markevitch et al. The time-scale for electrons and protons to reach temperature equilibrium can exceed a few ×109 years beyond radii of a megaparsec, if the intracluster gas is assumed to be at the usual cluster virial temperature. If a cluster merger has occurred within that time causing the protons, but not the electrons, to be rapidly heated then a small negative temperature gradient can result. This gradient is larger in clusters with higher temperatures and steeper density profiles. Applying these considerations to the cluster of galaxies A2163, we conclude that, more plausibly, the observed gradient is due to a lack of hydrostatic equilibrium following a merger.