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We analyse the influence of the stochastic particle acceleration for the evolution of the electron spectrum. We assume that all investigated spectra are generated inside a spherical, homogeneous source and also analyse the synchrotron and…

Astrophysics · Physics 2009-11-11 K. Katarzynski , G. Ghisellini , A. Mastichiadis , F. Tavecchio , L. Maraschi

Supernova remnants are believed to be a major source of cosmic-rays in the Galaxy. As their progenitors are commonly found clustered in OB associations, one has to consider the possibility of collective effects in the acceleration process.…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Gilles Ferrand , Alexandre Marcowith

The theory of diffusive acceleration of energetic particles at shock fronts assumes charged particles undergo spatial diffusion in a uniform magnetic field. If, however, the magnetic field is not uniform, but has a stochastic or braided…

Astrophysics · Physics 2007-05-23 J. G. Kirk , P. Duffy , Y. A. Gallant

About 1/3 of X-ray-luminous clusters show smooth, Mpc-scale radio emission, known as giant radio haloes. One promising model for radio haloes is Fermi-II acceleration of seed relativistic electrons by compressible turbulence. The origin of…

High Energy Astrophysical Phenomena · Physics 2017-01-11 Anders Pinzke , S. Peng Oh , Christoph Pfrommer

One of the most important challenges for the largely accepted idea that Galactic CRs are accelerated in SNR shocks is the maximum energy at which particles can be accelerated. The resonant streaming instability, long invoked for magnetic…

High Energy Astrophysical Phenomena · Physics 2015-07-23 Martina Cardillo , Elena Amato , Pasquale Blasi

In this study we predict the total distributions of powerful (FR II) active double-lobed radio galaxies and ghost sources, and their observable distribution in the X-ray sky. We develop an analytic model for the evolution of the lobe…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 P. Mocz , A. C. Fabian , Katherine M. Blundell

Based on the drift-kinetic theory, we develop a model for particle acceleration and transport in solar flares. The model describes the evolution of the particle distribution function by means of a numerical simulation of the drift-kinetic…

Solar and Stellar Astrophysics · Physics 2015-05-18 T. Minoshima , S. Masuda , Y. Miyoshi

The radio spectra of many shell-type supernova remnants show deviations from those expected on theoretical grounds. In this paper we determine the effect of stochastic reacceleration on the spectra of electrons in the GeV band and at lower…

High Energy Astrophysical Phenomena · Physics 2015-01-28 M. Pohl , A. Wilhelm , I. Telezhinsky

We consider evolution properties of galaxies and quasars with steep radio spectrum at the decametre band from the UTR-2 catalogue. The ratios of source's monochromatic luminosities at the decametre and high-frequency bands display the…

Astrophysics of Galaxies · Physics 2016-10-19 Alla Miroshnichenko

Despite the great variation in the light curves of Gamma Ray Burst (GRB) prompt emission, their spectral energy distribution is generally curved and broadly peaked. In particular, their spectral evolution is well described by the…

High Energy Astrophysical Phenomena · Physics 2015-05-27 F. Massaro , J. E. Grindlay

Radio relic sources in galaxy clusters are often described as the remnants of powerful radio galaxies. Here we develop a model for the evolution of such relics after the jets cease to supply energy to the lobes. This includes the treatment…

Astrophysics · Physics 2009-11-07 Christian R. Kaiser , Garret Cotter

The evolution of the radio emission from Sco X-1 is determined from a 56-hour continuous VLBI observation and from shorter observations over a four-year period. The radio source consists of a variable core near the binary, and two variable…

Astrophysics · Physics 2009-11-06 E. B. Fomalont , B. J. Geldzahler , C. F. Bradshaw

We study the evolution of the energy spectrum of cosmic-ray electrons accelerated at spherically expanding shocks with low Mach numbers and the ensuing spectral signatures imprinted in radio synchrotron emission. Time-dependent simulations…

High Energy Astrophysical Phenomena · Physics 2017-01-18 Hyesung Kang

We test the models of synchrotron emission presented in Part I of this series (Lloyd & Petrosian, these proceedings) against the distributions and evolution of GRB spectral parameters (particularly the low energy index, $\alpha$). With…

Astrophysics · Physics 2018-11-06 Nicole M. Lloyd-Ronning , Vahe' Petrosian , Robert D. Preece

Radiative cooling of electron beams interacting with counter-propagating electromagnetic waves is analyzed, taking into account the quantum modification of the radiation friction force. Central attention is paid to the evolution of the…

Context. The origin of coronal type-II radio bursts and of their band-splitting are still not fully understood. Aims. To make progress in solving this problem on the basis of one extremely well observed solar eruptive event. Methods. The…

Solar and Stellar Astrophysics · Physics 2015-06-11 I. Zimovets , N. Vilmer , A. C. -L. Chian , I. Sharykin , A. Struminsky

We discuss the spectrum arising from synchrotron emission by fast cooling (FC) electrons, when fresh electrons are continually accelerated by a strong blast wave, into a power law distribution of energies. The FC spectrum was so far…

Astrophysics · Physics 2009-10-31 Jonathan Granot , Tsvi Piran , Re'em Sari

Particle acceleration in relativistic shocks is not a very well understood subject. Owing to that difficulty, radiation spectra from relativistic shocks, such as those in GRB afterglows, have been often modelled by making assumptions about…

Astrophysics · Physics 2009-11-13 L. Resmi , D. Bhattacharya

The low-energy spectra of gamma-ray bursts' (GRBs) prompt emission are closely related to the energy distribution of electrons, which is further regulated by their cooling processes. We develop a numerical code to calculate the evolution of…

High Energy Astrophysical Phenomena · Physics 2018-01-16 Jin-Jun Geng , Yong-Feng Huang , Xue-Feng Wu , Bing Zhang , Hong-Shi Zong

Shear particle acceleration is a promising candidate for the origin of extended high-energy emission in extra-galactic jets. In this paper, we explore the applicability of a shear model to 24 X-ray knots in the large-scale jets of FR II…

High Energy Astrophysical Phenomena · Physics 2023-08-23 Jia-Chun He , Xiao-Na Sun , Jie-Shuang Wang , Frank M. Rieger , Ruo-Yu Liu , En-Wei Liang