相关论文: Rapid TeV variability in Blazars as result of Jet-…
M87 has been recently shown to be a TeV source which is likely to be variable. Based on this, and on contemporaneous optical and X-ray monitoring, we argue that the source of the TeV emission is the core of M87 and not one of two jet knots…
Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the stellar envelope is a widely discussed scenario for gamma-ray burst production. For very extended or slow rotating stars, the fireball may be…
A hard TeV $\gamma$-ray component excess over the single-zone leptonic model prediction (TeV excess) is observed in the spectral energy distributions (SEDs) of some BL Lacs. Its origin is uncertain. We revisit this issue with four BL Lacs…
It is proposed that the variable TeV emission observed in M87 may be produced in a starved magnetospheric region, above which the outflow associated with the VLBA jet is established. It is shown that annihilation of MeV photons emitted by…
We have developed a model for the variability of gamma ray emission in jets of active galactic nuclei in which the variability arises as a result of photon-photon pair production interactions with X-rays emitted by a hot spot in the inner…
The broad high-energy spectral component in blazars is usually attributed to various inverse Compton scattering processes in the relativistic jet, but has not been clearly identified in most cases due to degeneracies in physical models. AP…
Broadband spectral energy distributions (SEDs) are complied from literature for 24 TeV BL Lac objects. Two SEDs, which are identified as low and high states with their flux densities at $1\ {\rm TeV}$ ($F_{1 TeV}$), are available for each…
In this paper we discuss models of the X-rays and TeV gamma-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole owing to the strong electric fields…
We report on the variations of the physical parameters of the jet observed in the blazar Mrk 421, and discuss the origin of X-ray flares in the jet, based on the analysis of the several spectral energy distributions (SEDs). The SEDs are…
We analyze how the spectrum of synchrotron and inverse Compton radiation from a narrow relativistic jet changes with the observation angle. It is shown that diversity of acceleration mechanisms (in particular, taking the converter mechanism…
There is an increasing number of observational evidence that very high energy gamma-rays in radio-loud active galactic nuclei are produced in the direct vicinity of a supermassive black hole (SMBH), close to the base of a relativistic jet.…
Measurements from astroparticle experiments, such as the 2017 flare associated with the source TXS 0506+056, indicate that blazars act as multi-messenger (MM; radiation and neutrinos) factories. Theoretically, the particle acceleration…
We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6-minute exposure,…
It's generally believed that young and rapidly rotating pulsars are important sites of particle's acceleration, in which protons can be accelerated to relativistic energy above the polar cap region if the magnetic moment is antiparallel to…
Long TeV $\gamma$-ray campaigns have been carried out to study the spectrum, variability and duty cycle of the BL Lac object Markarian 421. These campaigns have given some evidence of the presence of protons in the jet: i) Its spectral…
Rapid flares from blazars in very high energy (VHE) $\gamma$-rays challenge the common understanding of jets of active galactic nuclei (AGNs). The same population of ultra-relativistic electrons is often thought to be responsible for both…
Accreting black holes produce powerful relativistic plasma jets which emit radiation across all observable wavelengths but the details of the initial acceleration and confinement of the jet are uncertain. We apply an innovative new model…
The VERITAS Collaboration recently reported the detection of very-high-energy (VHE) gamma-ray emission from the prototypical radio quasar 3C273. The temporal and the spectral properties of this component do not appear compatible with the…
Context. Very high-energy (VHE) $\gamma$-ray measurements of distant TeV blazars can be nicely explained by TeV spectra induced by ultra high-energy cosmic rays. Aims. We develop a model for a plausible origin of hard spectra in distant TeV…
Black-hole driven relativistic astrophysical jets, such as blazars and gamma-ray bursts (GRBs), are powerful sources of electromagnetic radiation. Their emission is powered by some energy dissipation and particle acceleration mechanism…