scholarly journals Theory of “Jitter” Radiation from Small‐Scale Random Magnetic Fields and Prompt Emission from Gamma‐Ray Burst Shocks

2000 ◽  
Vol 540 (2) ◽  
pp. 704-714 ◽  
Author(s):  
Mikhail V. Medvedev
Keyword(s):  
Magnetic Fields ◽  
Gamma Ray ◽  
Small Scale ◽  
Gamma Ray Burst ◽  
Jitter Radiation ◽  
Prompt Emission

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.

GRB PROMPT EMISSION: TURBULENCE, MAGNETIC FIELD AND JITTER RADIATION

2012 ◽  
Vol 08 ◽  
pp. 231-234
Author(s):  
JIRONG MAO
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
High Energy ◽  
Maximum Energy ◽  
Gamma Ray Bursts ◽  
Small Scale ◽  
Relativistic Electrons ◽  
Jitter Radiation ◽  
High Energy Emission ◽  
Prompt Emission

The jitter radiation, which is the emission of relativistic electrons in the random and small-scale magnetic field, is utilized to investigate the high-energy emission of gamma-ray bursts. We produce the random and small-scale magnetic field using turbulent scenario. The electrons can be accelerated by stochastic acceleration. We also estimate the acceleration and cooling timescales, aiming to identify the validation of jitter regime under the GRB fireball framework. The possible maximum energy of electrons in our case is estimated as well.

scholarly journals Simulation of relativistic shocks and associated radiation from turbulent magnetic fields

2010 ◽  
Vol 6 (S275) ◽  
pp. 354-357 ◽  
Author(s):  
K.-I. Nishikawa ◽  
J. Niemiec ◽  
M. Medvedev ◽  
B. Zhang ◽  
P. Hardee ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Small Scale ◽  
Spectral Structure ◽  
Relativistic Shocks ◽  
Electron Positron ◽  
Jitter Radiation ◽  
Transverse Deflection

AbstractRecent PIC simulations of relativistic electron-positron (electron-ion) jets injected into a stationary medium show that particle acceleration occurs in the shocked regions. Simulations show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields and for particle acceleration. These magnetic fields contribute to the electron's transverse deflection behind the shock. The “jitter” radiation from deflected electrons in turbulent magnetic fields has different properties from synchrotron radiation calculated in a uniform magnetic field. This jitter radiation may be important for understanding the complex time evolution and/or spectral structure of gamma-ray bursts, relativistic jets in general, and supernova remnants. In order to calculate radiation from first principles and go beyond the standard synchrotron model, we have used PIC simulations. We will present detailed spectra for conditions relevant to various astrophysical sites of collisionless shock formation. In particular we will discuss application to GRBs and SNRs.

scholarly journals Radiation from accelerated particles in shocks

2011 ◽  
Vol 7 (S279) ◽  
pp. 371-372
Author(s):  
K.-I. Nishikawa ◽  
B. Zhang ◽  
E. J. Choi ◽  
K. W. Min ◽  
J. Niemiec ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Small Scale ◽  
Spectral Structure ◽  
Electron Positron ◽  
Jitter Radiation ◽  
Transverse Deflection ◽  
Accelerated Particles

AbstractRecent PIC simulations of relativistic electron-positron (electron-ion) jets injected into a stationary medium show that particle acceleration occurs in the shocked regions. Simulations show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields and for particle acceleration. These magnetic fields contribute to the electron's transverse deflection behind the shock. The “jitter” radiation from deflected electrons in turbulent magnetic fields has properties different from synchrotron radiation calculated in a uniform magnetic field. This jitter radiation may be important for understanding the complex time evolution and/or spectral structure of gamma-ray bursts, relativistic jets in general, and supernova remnants. In order to calculate radiation from first principles and go beyond the standard synchrotron model, we have used PIC simulations. We present synthetic spectra to compare with the spectra obtained from Fermi observations.

scholarly journals Prompt emission from the counter jet of a short gamma-ray burst

2018 ◽  
Vol 2018 (3) ◽  
Author(s):  
Ryo Yamazaki ◽  
Kunihito Ioka ◽  
Takashi Nakamura
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst ◽  
Prompt Emission

scholarly journals GAMMA-RAY BURSTS: PROGRESS, PROBLEMS & PROSPECTS

2004 ◽  
Vol 19 (15) ◽  
pp. 2385-2472 ◽  
Author(s):  
BING ZHANG ◽  
PETER MÉSZÁROS
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Current Understanding ◽  
Shock Model ◽  
Gamma Ray Burst ◽  
Prompt Emission

The cosmological gamma-ray burst (GRB) phenomenon is reviewed. The broad observational facts and empirical phenomenological relations of the GRB prompt emission and afterglow are outlined. A well-tested, successful fireball shock model is introduced in a pedagogical manner. Several important uncertainties in the current understanding of the phenomenon are reviewed, and prospects of how future experiments and extensive observational and theoretical efforts may address these problems are discussed.

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