相关论文: Variability and Unification of Blazars and Gamma R…
The radiation observed by blazars is believed to originate from the transformation of bulk kinetic energy of relativistic jets into random energy. A simple way to achieve this is to have an intermittent central power source, producing…
The radiation we observe from blazars is most likely the product of the transformation of bulk kinetic energy into random energy. This process must have a relatively small efficiency (e.g. 10%) if jets are to power the extended…
The kinetic energy of bulk relativistic plasma ejected from the central engine of blazars is converted into nonthermal particle energy in the comoving frame through a process of sweeping up material from the surrounding medium. The…
In almost any scenario for 'cosmological' gamma-ray bursts (and in many models where they originate in our own Galaxy), the initial energy density is so large that the resulting relativistic plasma expands with $v\sim c$ producing a blast…
BeppoSAX is best known for its role in the disclosure of the Gamma-Ray Burst mystery, but it has also improved our understanding of jetted sources in general, and blazars in particular. On the interpretational side, we are curious to see if…
As powerful gamma-ray engines, blazars -- relativistic plasma jets launched toward Earth from active galactic nuclei -- are manifestly high-energy particle accelerators. Yet, exactly how these jets accelerate particles as well as what they…
A variety of arguments suggest that the most common form of gamma-ray bursts (GRBs), those longer than a few seconds, involve the formation of black holes in supernova-like events. Two kinds of ``collapsar'' models are discussed, those in…
The extragalactic gamma-ray sky is dominated by two classes of sources: Gamma-Ray Bursts (GRBs) and radio loud active galactic nuclei whose jets are pointing at us (blazars). We believe that the radiation we receive from them originates…
A pedagogical derivation is presented of the ``fireball'' model of gamma-ray bursts, according to which the observable effects are due to the dissipation of the kinetic energy of a relativistically expanding wind, a ``fireball.'' The main…
Blazars and Gamma Ray Bursts (GRBs) are the fastest objects known so far. The radiation we see from these sources originates in a jet of similar aperture angle, and we think it is the result of the conversion of some of the jet kinetic…
The standard blazar paradigm consists of a supermassive black hole that expels relativistic jets of magnetized plasma in our direction. This plasma entrains nonthermal synchrotron-emitting electrons that furthermore scatter…
Gamma-ray bursts (GRBs) are a mixed class of sources consisting of, at least, the long duration and short-hard subclasses, the X-ray flashes, and the low-luminosity GRBs. In all cases, the release of enormous amounts of energy on a short…
The possibility that gamma-ray bursts (GRBs) were not isotropic emissions was devised theoretically as a way to ameliorate the huge energetic budget implied by the standard fireball model for these powerful phenomena. However, the mechanism…
The Gamma-Ray Bursts (GRBs) offer the unprecedented opportunity to observe for the first time the blackholic energy extracted by the vacuum polarization during the process of gravitational collapse to a black hole leading to the formation…
Cosmological GRBs are discussed with an emphasis on their plausible connection with black holes. GRBs can be triggered by collapse of stellar-mass objects that leads to formation of a black hole and a transient debris disk with a huge…
Pulsar Wind Nebulae, Blazars, Gamma Ray Bursts and Magnetars all contain regions where the electromagnetic energy density greatly exceeds the plasma energy density. These sources exhibit dramatic flaring activity where the electromagnetic…
The idea that the vacuum polarization process occurring during gravitational collapse to a black hole endowed with electromagnetic structure (EMBH) could be the origin of gamma ray bursts (GRBs) is further developed. EMBHs in the range 3.2…
We calculate the spectrum of blast wave models of gamma-ray burst sources, for various assumptions about the magnetic field density and the relativistic particle acceleration efficiency. For a range of physically plausible models we find…
We propose that repeated photoexcitation/ionization of high Z atoms of highly relativistic flows by star light in dense stellar regions followed by emission of decay/recombination photons, which are beamed and boosted to gamma ray energies…
Being the most extreme explosions in the universe, gamma-ray bursts (GRBs) provide a unique laboratory to study various plasma physics phenomena. The complex lightcurve and broad-band, non-thermal spectra indicate a very complicated system…