scholarly journals High energy emission from galaxy clusters and particle acceleration due to MHD turbulence

2009 ◽  
Author(s):  
G. Brunetti ◽  
P. Blasi ◽  
R. Cassano ◽  
S. Gabici ◽  
Denis Bastieri ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Galaxy Clusters ◽  
High Energy ◽  
Mhd Turbulence ◽  
Energy Emission ◽  
High Energy Emission

scholarly journals Particle Reacceleration by Turbulence and Radio Constraints on Multimessenger High-energy Emission from the Coma Cluster

2021 ◽  
Vol 922 (2) ◽  
pp. 190
Author(s):  
Kosuke Nishiwaki ◽  
Katsuaki Asano ◽  
Kohta Murase
Keyword(s):  
Galaxy Clusters ◽  
Gamma Ray ◽  
Radial Profile ◽  
Planck Equation ◽  
High Energy ◽  
Coma Cluster ◽  
Radio Halo ◽  
Energy Emission ◽  
Neutrino Fluxes ◽  
High Energy Emission

Abstract Galaxy clusters are considered to be gigantic reservoirs of cosmic rays (CRs). Some of the clusters are found with extended radio emission, which provides evidence for the existence of magnetic fields and CR electrons in the intra-cluster medium. The mechanism of radio halo (RH) emission is still under debate, and it has been believed that turbulent reacceleration plays an important role. In this paper, we study the reacceleration of CR protons and electrons in detail by numerically solving the Fokker–Planck equation, and show how radio and gamma-ray observations can be used to constrain CR distributions and resulting high-energy emission for the Coma cluster. We take into account the radial diffusion of CRs and follow the time evolution of their one-dimensional distribution, by which we investigate the radial profile of the CR injection that is consistent with the observed RH surface brightness. We find that the required injection profile is nontrivial, depending on whether CR electrons have a primary or secondary origin. Although the secondary CR electron scenario predicts larger gamma-ray and neutrino fluxes, it is in tension with the observed RH spectrum for hard injection indexes, α < 2.45. This tension is relaxed if the turbulent diffusion of CRs is much less efficient than the fiducial model, or the reacceleration is more efficient for lower-energy CRs. In both the secondary and primary scenario, we find that galaxy clusters can make a sizable contribution to the all-sky neutrino intensity if the CR energy spectrum is nearly flat.

scholarly journals High Energy Emission of Symbiotic Recurrent Novae: RS Oph and V407 Cyg

2012 ◽  
Vol 21 (1-2) ◽  
Author(s):  
M. Hernanz ◽  
V. Tatischeff
Keyword(s):  
Particle Acceleration ◽  
White Dwarf ◽  
Pion Production ◽  
Supernova Remnant ◽  
High Energy ◽  
Energy Emission ◽  
Inverse Compton ◽  
Red Giant ◽  
Symbiotic Binaries ◽  
High Energy Emission

AbstractRecurrent novae occurring in symbiotic binaries are candidate sources of high energy photons, reaching GeV energies. Such emission is a consequence of particle acceleration leading to pion production. the shock between matter ejected by the white dwarf, undergoing a nova explosion, and the wind from the red giant companion are responsible for such a process, which mimics a supernova remnant but with much smaller energetic output and much shorter time scales. Inverse Compton can also be responsible for high energy emission. Recent examples are V407 Cyg, detected by Fermi, and RS Oph, which unfortunately exploded in 2006, before Fermi was launched.

High‐Energy Emission from the TeV Blazar Markarian 501 during Multiwavelength Observations in 1996

1999 ◽  
Vol 514 (1) ◽  
pp. 138-147 ◽  
Author(s):  
J. Kataoka ◽  
J. R. Mattox ◽  
J. Quinn ◽  
H. Kubo ◽  
F. Makino ◽  
...  
Keyword(s):  
High Energy ◽  
Energy Emission ◽  
High Energy Emission ◽  
Multiwavelength Observations
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