We simulate the evolution of relativistic electrons injected into the medium of a small galaxy cluster by a central radio galaxy, studying how the initial jet power affects the dispersal and the emission properties of radio plasma. By coupling passive tracer particles to adaptive-mesh cosmological MHD simulations, we study how cosmic-ray electrons are dispersed as a function of the input jet power. We also investigate how the latter affects the thermal and non-thermal properties of the intracluster medium, with differences discernible up to $\sim$ Gyr after the start of the jet. We evolved the energy spectra of cosmic-ray electrons, subject to energy losses that are dominated by synchrotron and inverse Compton emission as well as energy gains via re-acceleration by shock waves and turbulence. We find that in the absence of major mergers the amount of re-acceleration experienced by cosmic-ray electrons is not enough to produce long-lived detectable radio emissions. However, for all simulations the role of re-acceleration processes is crucial to maintain a significant and volume-filling reservoir of fossil electrons ($\gamma \sim 10^3$) for several Gyrs after the first injection by jets. This is important to possibly explain recent discoveries of cluster-wide emission and other radio phenomena in galaxy clusters.

Life cycle of cosmic-ray electrons in the intracluster medium

F. Vazza
Primo
Data Curation
;
D. Wittor;M. Brienza;G. Brunetti;F. Brighenti;T. Pasini
2022

Abstract

We simulate the evolution of relativistic electrons injected into the medium of a small galaxy cluster by a central radio galaxy, studying how the initial jet power affects the dispersal and the emission properties of radio plasma. By coupling passive tracer particles to adaptive-mesh cosmological MHD simulations, we study how cosmic-ray electrons are dispersed as a function of the input jet power. We also investigate how the latter affects the thermal and non-thermal properties of the intracluster medium, with differences discernible up to $\sim$ Gyr after the start of the jet. We evolved the energy spectra of cosmic-ray electrons, subject to energy losses that are dominated by synchrotron and inverse Compton emission as well as energy gains via re-acceleration by shock waves and turbulence. We find that in the absence of major mergers the amount of re-acceleration experienced by cosmic-ray electrons is not enough to produce long-lived detectable radio emissions. However, for all simulations the role of re-acceleration processes is crucial to maintain a significant and volume-filling reservoir of fossil electrons ($\gamma \sim 10^3$) for several Gyrs after the first injection by jets. This is important to possibly explain recent discoveries of cluster-wide emission and other radio phenomena in galaxy clusters.
F. Vazza; D. Wittor; L. Di Federico; M. Brüggen; M. Brienza; G. Brunetti; F. Brighenti; T. Pasini
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/903745
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