Second-order Fermi Reacceleration Mechanisms and Large-Scale Synchrotron Radio Emission in Intracluster Bridges.

  title={Second-order Fermi Reacceleration Mechanisms and Large-Scale Synchrotron Radio Emission in Intracluster Bridges.},
  author={G. Brunetti and F. Vazza},
  journal={Physical review letters},
  volume={124 5},
Radio observations at low frequencies with the low frequency array (LOFAR) start discovering gigantic radio bridges connecting pairs of massive galaxy clusters. These observations probe unexplored mechanisms of in situ particle acceleration that operate on volumes of several Mpc^{3}. Numerical simulations suggest that such bridges are dynamically complex and that weak shocks and super-Alfvénic turbulence can be driven across the entire volume of these regions. In this Letter, we explore, for… Expand
Fast magnetic field amplification in distant galaxy clusters
In the present-day Universe, magnetic fields pervade galaxy clusters 1 and have strengths of a few microgauss, as measured from Faraday rotation 2 . Evidence for cluster magnetic fields is alsoExpand
Turbulent pressure support and hydrostatic mass bias in the intracluster medium
The degree of turbulent pressure support by residual gas motions in galaxy clusters is not well known. Mass modelling of combined X-ray and Sunyaev Zel'dovich observations provides an estimate ofExpand
Nonthermal phenomena in the center of Abell 1775
Context. Thermal gas in the center of galaxy clusters can show substantial motions that generate surface brightness and temperature discontinuities known as cold fronts. The motions may be triggeredExpand
Radio observations of the merging galaxy cluster system Abell 3391-Abell 3395
The pre-merging system of galaxy clusters Abell 3391-Abell 3395 located at a mean redshift of 0.053 has been observed at 1 GHz in an ASKAP/EMU Early Science observation as well as in X-rays withExpand
MeerKAT’s discovery of a radio relic in the bimodal merging cluster A2384
We present the discovery of a single radio relic located at the edge of the galaxy cluster A2384, using the MeerKAT radio telescope. A2384 is a nearby ($z$ = 0.092), low mass, complex bimodal,Expand
Discovery of a supercluster in the eROSITA Final Equatorial Depth Survey: X-ray properties, radio halo, and double relics
We examine the X-ray, optical, and radio properties for the members clusters of a new supercluster discovered during the SRG/eROSITA Performance Verification phase. In the 140 deg2 eROSITA FinalExpand
Discovery of magnetic fields along stacked cosmic filaments as revealed by radio and X-ray emission
Diffuse filaments connect galaxy clusters to form the cosmic web. Detecting these filaments could yield information on the magnetic field strength, cosmic ray population and temperature ofExpand
Troubled cosmic flows: turbulence, enstrophy, and helicity from the assembly history of the intracluster medium
Both simulations and observations have shown that turbulence is a pervasive phenomenon in cosmic scenarios, yet it is particularly difficult to model numerically due to its intrinsically multiscaleExpand
Unravelling cosmic velocity flows: a Helmholtz-Hodge decomposition algorithm for cosmological simulations
A new method for performing a Helmholtz-Hodge decomposition of the velocity field around a massive galaxy cluster, based on solving elliptic equations for a scalar and a vector potential, from which the compressive and the solenoidal velocity fields are derived through differentiation. Expand
Particle Acceleration by Relativistic Magnetic Reconnection Driven by Kink Instability Turbulence in Poynting Flux–Dominated Jets
Particle acceleration in magnetized relativistic jets still puzzles theorists. In this work, we investigate the acceleration of particles injected into a three-dimensional relativisticExpand


Diffusive Shock Acceleration Simulations of Radio Relics
Recent radio observations have identified a class of structures, so-called radio relics, in clusters of galaxies. The radio emission from these sources is interpreted as synchrotron radiation fromExpand
The challenge of turbulent acceleration of relativistic particles in the intra-cluster medium
Acceleration of cosmic-ray electrons (CRe) in the intra-cluster-medium (ICM) is probed by radio observations that detect diffuse, Mpc-scale, synchrotron sources in a fraction of galaxy clusters.Expand
Stochastic reacceleration of relativistic electrons by turbulent reconnection: a mechanism for cluster-scale radio emission?
In this paper we investigate a situation where relativistic particles are reaccelerated diffusing across regions of reconnection and magnetic dynamo in super-Alfvenic, incompressible large-scaleExpand
Resolved magnetic dynamo action in the simulated intracluster medium
Faraday rotation and synchrotron emission from extragalactic radio sources give evidence for the presence of magnetic fields extending over ˜ Mpc scales. However, the origin of these fields remainsExpand
A Diffusive Shock Acceleration Model for Protons in Weak Quasi-parallel Intracluster Shocks
Low sonic Mach number shocks form in the intracluster medium (ICM) during the formation of the large-scale structure of the universe. Nonthermal cosmic-ray (CR) protons are expected to be acceleratedExpand
Cluster mergers and non‐thermal phenomena: a statistical magneto‐turbulent model
There is now firm evidence that the intracluster medium (ICM) consists of a mixture of hot plasma, magnetic fields and relativistic particles. The most important evidence for non-thermal phenomena inExpand
Cluster mergers and non-thermal phenomena: expectations from a statistical magneto-turbulent model
The most important evidences for non-thermal phenomena in galaxy clusters comes from the spectacular synchrotron radio emission diffused over Mpc scale observed in a growing number of massiveExpand
Relativistic protons in the Coma galaxy cluster: first gamma-ray constraints ever on turbulent reacceleration
The Fermi-LAT (Large Area Telescope) collaboration recently published deep upper limits to the gamma-ray emission of the Coma cluster, a cluster hosting the prototype of giant radio haloes. In thisExpand
Particle reacceleration by compressible turbulence in galaxy clusters: effects of a reduced mean free path
Direct evidence forinsitu particle acceleration mechanisms in the intergalactic medium (IGM) is provided by the diffuse Mpc-scale synchrotron emissions observed from galaxy clusters. It has beenExpand
The Interplay of Magnetically Dominated Turbulence and Magnetic Reconnection in Producing Nonthermal Particles
Magnetized turbulence and magnetic reconnection are often invoked to explain the nonthermal emission observed from a wide variety of astrophysical sources. By means of fully-kinetic 2D and 3D PICExpand