Related papers: Relativistic Wind Bubbles and Afterglow Signatures
Recent observations suggest that $\gamma$-ray bursts (GRBs) and their afterglows are produced by jets of highly relativistic cannonballs (CBs), emitted in supernova (SN) explosions. The CBs, reheated by their collision with the shell, emit…
We believe that the radiation we receive from Gamma-Ray Bursts (GRBs) and radio loud Active Galacti Nuclei (AGNs) originates from the transformation of bulk relativistic motion into random energy. Mechanisms to produce, collimate and…
We present a model for relativistic jets which generates a particular angular distribution of Lorentz factor and energy per solid angle. We consider a fireball with specific internal energy E/M launched with bulk Lorentz factor \gamma_B.…
Three-dimensional special relativistic magnetohydrodynamic simulations are performed to investigate properties of the downstream turbulence generated by the interaction between a relativistic shock wave and multiple clumps. We analyze the…
The SN explosion in the closed binary can give the magnetospheric flare possessing the properties of GRB. The SN shock, flowing around the magnetosphere of a magnetized neutron star or a white dwarf, produces a narrow magnetic tail 10^9 cm…
We construct a model of a relativistic fireball or light--like shell of matter by considering a spherically symmetric moving gravitating mass experiencing an impulsive deceleration to rest. We take this event to be followed by the mass…
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…
In the Poynting Flux dominated outflow (the initial ratio of the electromagnetic energy flux to the particle energy flux $\sigma_0\gg1$) model for Gamma-ray bursts, nearly half of the internally dissipated magnetic energy is converted into…
Most recent extragalactic models of gamma-ray bursts consider the expansion of a relativistic blast wave, emanating from a solar-mass type progenitor, into the surrounding interstellar medium as the site for their activity. The popular…
The connection between Gamma-Ray Bursts (GRBs) and their afterglows is currently not well understood. Afterglow models of synchrotron emission generated by external shocks in the GRB fireball model predict emission detectable in the…
The extreme hypothesis that essentially all types of ultrarelativistic outflow -- specifically AGN jets, pulsar wind nebulae and GRB --are electromagnetic, rather than gas dynamical, phenomena is considered. Electromagnetic flows are…
The progenitor stars of long Gamma-Ray Bursts (GRBs) are thought to be Wolf-Rayet stars, which generate a massive and energetic wind. Nevertheless, about 25 percent of all GRB afterglows light curves indicate a constant density medium close…
To demonstrate the magnetic energy dissipation via relativistic shocks, we carry out spherically symmetrical one-dimensional special relativistic magneto-hydrodynamic simulations of highly magnetised outflows with an adaptive mesh…
Observations of very early multi-wavelength afterglows are critical to reveal the properties of the radiating fireball and its environment as well as the central engine of gamma-ray bursts (GRBs). We report our optical observations of GRB…
We calculate the creation of electron--positron pairs in Gamma-Ray Bursts (GRBs) resulting from the collision between scattered and outward moving gamma-ray photons. The number of pairs exceeds the number of ambient medium electrons…
We consider GRBs that occur inside pulsar wind bubbles (PWBs), in the context of the supranova model, where initially a supernova explosion takes place, leaving behind a supra-massive neutron star (SMNS), which eventually loses its…
Hydrodynamical simulations of the last inspiral stages and the final coalescence of a double neutron star system are used to investigate the power of the neutrino-driven wind, the energy and momentum of the fireball produced via $\nu…
The collapse of massive stars drives explosions that power relativistic fireballs. If only a small amount of matter is entrained, such clean fireballs can expand with Lorentz factors $\Gamma> 100$, accounting for gamma-ray bursts (GRBs). It…
The afterglow emission that follows gamma-ray bursts (GRBs) contains valuable information about the circumburst medium and, therefore, about the GRB progenitor. Theoretical studies of GRB blast waves, however, are often limited to simple…
We use a parent sample of 118 gamma-ray burst (GRB) afterglows, with known redshift and host galaxy extinction, to separate afterglows with and without signatures of dominant reverse-shock emission and to determine which physical conditions…