scholarly journals Gamma-ray halos as a measure of intergalactic magnetic fields: A classical moment problem

2011 ◽  
Vol 84 (6) ◽  
Author(s):  
Markus Ahlers
Keyword(s):  
Magnetic Fields ◽  
Moment Problem ◽  
Gamma Ray ◽  
Classical Moment Problem

scholarly journals Gamma-Ray Bursts as Sources of Strong Magnetic Fields

2016 ◽  
pp. 481-528
Author(s):  
Jonathan Granot ◽  
Tsvi Piran ◽  
Omer Bromberg ◽  
Judith L. Racusin ◽  
Frédéric Daigne
Keyword(s):  
Magnetic Fields ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Strong Magnetic Fields

Gamma-Ray Bursts and Magnetic Fields

2008 ◽  
Author(s):  
Shiho Kobayashi ◽  
Yong-Feng Huang ◽  
Zi-Gao Dai ◽  
Bing Zhang
Keyword(s):  
Magnetic Fields ◽  
Gamma Ray ◽  
Gamma Ray Bursts

scholarly journals The Effect of Magnetic Fields Upon Cosmic X-ray Spectra

1990 ◽  
Vol 115 ◽  
pp. 70-77
Author(s):  
P. Mészáros
Keyword(s):  
Magnetic Fields ◽  
Gamma Ray ◽  
Line Emission ◽  
Atomic Line ◽  
Photon Scattering ◽  
Theoretical Understanding ◽  
Strong Magnetic Fields ◽  
X Ray ◽  
Two Photon ◽  
The One

AbstractThe effect of strong magnetic fields (B ≳ 1011Gauss) upon various atomic line emission mechanisms in the X-ray range is considered, in particular for H and H-like or He-like ions, and a discussion of the detectability and significance of possible measurements is given. The cyclotron mechanism, the one- and two-photon scattering and the bremsstrahlung effects in a strong B are reviewed, as well as the role they play in determining X-ray spectra. These considerations are applied to typical models of X-ray pulsars and Gamma-ray bursters, contrasting observations of magnetic related features to the present theoretical understanding of these objects.

scholarly journals PARTICLE ACCELERATION, MAGNETIC FIELD GENERATION, AND ASSOCIATED EMISSION IN COLLISIONLESS RELATIVISTIC JETS

2008 ◽  
Vol 17 (10) ◽  
pp. 1761-1767 ◽  
Author(s):  
K.-I. NISHIKAWA ◽  
Y. MIZUNO ◽  
G. J. FISHMAN ◽  
P. HARDEE
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Small Scale ◽  
Spectral Structure ◽  
Relativistic Jets ◽  
Weibel Instability ◽  
Electron Positron ◽  
Jitter Radiation

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electron-positron) jets show that acceleration occurs within the downstream jet. Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electrons' transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties to synchrotron radiation which assumes a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

scholarly journals SIMULATION OF RELATIVISTIC JETS AND ASSOCIATED SELF-CONSISTENT RADIATION

2012 ◽  
Vol 08 ◽  
pp. 259-264 ◽  
Author(s):  
K.-I. NISHIKAWA ◽  
J. NIEMIEC ◽  
B. ZHANG ◽  
M. MEDVEDEV ◽  
P. HARDEE ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Lorentz Factor ◽  
Shock Structure ◽  
Spectral Structure ◽  
Relativistic Jets ◽  
Collisionless Shocks ◽  
Electron Positron ◽  
Transverse Deflection

Plasma instabilities are responsible not only for the onset and mediation of collisionless shocks but also for the associated acceleration of particles. We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection and, more generally, relativistic acceleration behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. The properties of the radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants.

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