Issue |
A&A
Volume 653, September 2021
|
|
---|---|---|
Article Number | A23 | |
Number of page(s) | 21 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/202140513 | |
Published online | 03 September 2021 |
Simulating the transport of relativistic electrons and magnetic fields injected by radio galaxies in the intracluster medium⋆
1
Dipartimento di Fisica e Astronomia, Universitá di Bologna, Via Gobetti 93/2, 40122 Bologna, Italy
e-mail: franco.vazza2@unibo.it
2
Hamburger Sternwarte, University of Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
3
Istituto di Radioastronomia, INAF, Via Gobetti 101, 40122 Bologna, Italy
Received:
8
February
2021
Accepted:
20
May
2021
Radio galaxies play an important role in the seeding of cosmic rays and magnetic fields in galaxy clusters. Here, we simulate the evolution of relativistic electrons injected into the intracluster medium by radio galaxies. Using passive tracer particles added to magnetohydrodynamical adaptive-mesh simulations, we calculated the evolution of the spectrum of relativistic electrons, taking into account energy losses and re-acceleration mechanisms associated with the dynamics of the intracluster medium. Re-acceleration can occur at shocks via diffusive shock acceleration, and in turbulent flows via second-order Fermi re-acceleration. This study confirms that relativistic electrons from radio galaxies can efficiently fill the intracluster medium over scales of several hundreds of Myr and that they create a stable reservoir of fossil electrons that remains available for further re-acceleration by shock waves and turbulent gas motions. Our results also show that late evolution of radio lobes and remnant radio galaxies is significantly affected by the dynamics of the surrounding intracluster medium. Here, the diffusive re-acceleration couples the evolution of relativistic particles to the gas perturbations. In the near future, deep radio observations, especially at low frequencies, will be able to probe such mechanisms in galaxy clusters.
Key words: acceleration of particles / magnetohydrodynamics (MHD) / radio continuum: general / methods: numerical / galaxies: clusters: intracluster medium
Movies associated to Figs. A.1 and A.2 are available at https://www.aanda.org
© ESO 2021
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