Related papers: Resolving Doppler-factor crisis in AGNs: non-stead…
Gamma-ray bursts (GRBs) are powered by ultra-relativistic jets. Usually a minimum value of the Lorentz factor of the relativistic bulk motion is obtained based on the argument that the observed high energy photons ($\gg {\rm MeV}$) can…
Relativistic jets in Galactic superluminals and extragalactic AGN may be surrounded by a wind near to the central engine. Theoretical analysis and numerical simulation reveal considerable stabilization of relativistic jet flow by a wind to…
We propose a straightforward and efficient mechanism for the high-energy emission of relativistic astrophysical jets associated with an exchange of interacting high-energy photons between the jet and the external environment. Physical…
We investigate hadronic and leptonic scenarios for the GeV--TeV gamma-ray emission from jets of the microquasar SS 433. The emission region of the TeV photons coincides with the X-ray knots, where electrons are efficiently accelerated. On…
The detection of a high-energy neutrino from the flaring blazar TXS 0506+056 and the subsequent discovery of a neutrino excess from the same direction have strengthened the hypothesis that blazars are cosmic neutrino sources. The lack,…
Relativistic jets are believed to be born magnetically dominated. Very and ultra-high energy cosmic rays can be efficiently accelerated by magnetic reconnection in these sources. We here demonstrate this directly, with no extrapolations to…
It is widely accepted that the Doppler deboosting effects exist in counter relativistic jets. However, people often neglect another important fact that both Doppler boosting and deboosting effects could happen in forward relativistic jets.…
Photon breeding in relativistic jets involves multiplication of high-energy photons propagating from the jet to the external environment and back with the conversion into electron-positron pairs. The exponential growth of the energy density…
Comprehensive VLBI and multi-waveband monitoring indicate that a single superluminal knot can cause a number of gamma-ray flares at different locations. However, the often very rapid variability timescale is a challenge to theoretical…
{\it Fermi Gamma-ray Space Telescope} observations of GRB110721A have revealed two emission components from the relativistic jet: emission from the photosphere, peaking at $\sim 100$ keV and a non-thermal component, which peaks at $\sim…
Gradual shear acceleration of energetic particles in gamma-ray burst (GRB) jets is considered. Special emphasis is given to the analysis of universal structured jets, and characteristic acceleration timescales are determined for a power-law…
The mechanism for flow generation in dense degenerate stellar atmospheres is suggested when the electron gas is degenerate and ions are assumed to be classical. It is shown, that there is a catastrophe in such system -- fast flows are…
The major multi-epoch VLBA programs are described and discussed in terms of relativistic beaming models. Broadly speaking the observed kinematics are consistent with models having a parent population which is only mildly relativistic but…
It is well known that if the most energetic cosmic rays ($E>10^{20}$ eV) were protons then their acceleration sites should possess some extreme properties, including gigantic luminosity. As no stationary sources with such properties are…
We use the complete MOJAVE 1.5 Jy sample of active galactic nuclei (AGN) to examine the gamma-ray detection statistics of the brightest radio-loud blazars in the northern sky. We find that 23% of these AGN were not detected above 0.1 GeV by…
TeV emission from BL Lacertae (BL) objects is commonly modeled as Synchrotron-Self Compton (SSC) radiation from relativistically moving homogeneous plasma blobs. In the context of these models, the blob Lorentz factors needed to reproduce…
The multi-wavelength spectrum observed from M87 extends from radio wavelengths up to TeV gamma-ray energies. The radio through GeV components have been interpreted successfully using SSC models based on misaligned blazar jets, but the…
Bright blazars were found to be prominent neutrino sources, and a number of IceCube events were associated with them over recent years. A particularly strong observational connection is present between neutrinos and blazars with bright,…
Most active galactic nuclei (AGN) lack prominent jets, and show modest radio emission and significant X-ray emission which arises mainly from the galactic core, very near from the central black hole. We use a quantitative scenario of such…
We investigate the dissipation of the bulk kinetic energy of a relativistic jet at different distances from the central power--house and analyse in detail how the dissipated energy is radiated away. We assume that the location of the…