Related papers: Particle Acceleration And Emission Processes In Mr…
Evidence for very hard, intrinsic $\gamma$-ray source spectra, as inferred after correction for absorption in the extragalactic background light (EBL), has interesting implications for the acceleration and radiation mechanisms acting in…
The spectral shape of the prompt emissions of gamma-ray bursts (GRBs) is typically expressed by the Band function: smooth joining of two power-law functions for high-energy and low-energy regions. To reveal the origin of the Band function,…
We study the temporal/spectral variability of two extragalactic TeV sources, Mrk 421 and Mrk 501, based on 5-year observations with the ASCA and RXTE satellites. We found that the peak of the synchrotron emission exists just in the X-ray…
The Letter takes up a question of what radio emission is produced by electrons at the very acceleration site of a solar flare. Specifically, we calculate incoherent radio emission produced within two competing acceleration…
The spectral energy distribution (SED) of blazars is generally understood through the standard one-zone synchrotron self-Compton (SSC) model, where a strong correlation between X-ray and TeV gamma-ray fluxes is expected. Recently, for Mrk…
Blazars emit non-thermal radiation in all frequency bands from radio to \gamma-rays. Additionally, they often exhibit rapid flaring events at all frequencies with doubling time scale of the TeV and X-ray flux on the order of minutes, and…
The {\gamma}-ray flares from the Crab nebula observed by AGILE and Fermi-LAT reaching GeV energies and lasting several days challenge the standard models for particle acceleration in pulsar wind nebulae, because the radiating electrons have…
PKS 1510-089 is one of the most variable blazars. Very high energy gamma ray emission from this source was observed by H.E.S.S. during March-April 2009 and by MAGIC from February 3 to April 3, 2012 quasi-simultaneously with multi-wavelength…
Recent multiwavelength observations of PKS 0208-512 by SMARTS, Fermi, and Swift revealed that gamma-ray and optical light curves of this flat spectrum radio quasars are highly correlated, but with an exception of one large optical flare…
The current detectors of gamma-ray emission specially at TeV energies have too poor resolution to determine whether this emission is produced in the jet or in the core, particularly of low luminous, non-blazar AGNs (like radio galaxies). In…
We test the synchrotron emission scenario for the very bright gamma-ray flare of blazar 3C 279 observed in 2015 June using time-dependent numerical simulations. A bulk Lorentz factor as high as 100 can bring the synchrotron maximum energy…
We test one-zone synchrotron self-Compton (SSC) models with high-quality multiwavelength spectral energy distribution (SED) data of Mrk 421. We use Markov chain Monte Carlo (MCMC) technique to fit twelve day-scale SEDs of Mrk 421 with…
We develop a model for stochastic acceleration of electrons in solar flares. As in several previous models, the electrons are accelerated by turbulent fast magnetosonic waves ("fast waves") via transit-time-damping (TTD) interactions. (In…
Synchrotron radiation of ultra-relativistic particles accelerated in a pulsar wind nebula may dominate its spectrum up to gamma-ray energies. Because of the short cooling time of the gamma-ray emitting electrons, the gamma-ray emission zone…
Highly variable Markarian 421 is a bright high synchrotron energy peaked blazar showing wide featureless non-thermal spectrum making it a good candidate for our study of intraday flux and spectral variations over time. We analyse its X-ray…
Recent near-IR (NIR) and X-ray observations of Sagittarius A*'s spectrum have yielded several strong constraints on the transient energization mechanism, justifying a re-examination of the stochastic acceleration model proposed previously…
We study the synchrotron radiation as the observed non-thermal X-ray emission from old pulsars ($\gtrsim1-10$Myr) to investigate the particle acceleration in their magnetospheres. We assume that the power-law component of the observed X-ray…
During the observation period 1997, the nearby Blazar Mkn 501 showed extremely strong emission and high variability. We examine multiwavelength aspects of this event using radio, optical, soft and hard X-ray and TeV data. We concentrate on…
The extremely bright optical flash that accompanied GRB 080319B suggested, at first glance, that the prompt $\gamma$-rays in this burst were produced by Synchrotron self Compton (SSC). We analyze here the observed optical and $\gamma$…
Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. The emitting region is sufficiently compact to let…