Related papers: Beaming effects in GRBs and orphan afterglows
Gamma-Ray Bursts (GRBs), short and intense pulses of low energy gamma-rays, have fascinated astronomers and astrophysicists since their unexpected discovery in the late sixties. During the last decade, several space missions: BATSE (Burst…
The discoveries that GRBs have X-ray, optical and radio afterglows have connected the study of GRBs to the rest of astronomy, and revolutionized the field. In this review, I discuss the implications that the observation of these afterglows…
A strong correlation is reported between gamma-ray burst (GRB) pulse lags and afterglow jet-break times for the set of bursts (seven) with known redshifts, luminosities, pulse lags, and jet-break times. This may be a valuable clue toward…
Gamma-ray bursts with long durations are widely thought to arise from the collapse of massive stars, where the wind environment is unavoidable. It is also believed that $\gamma$-ray bursts come from jets. Considering these two points in…
The optical afterglows of gamma-ray bursts can be used to probe the physics, geometry, and environments of gamma-ray bursts. In this article I discuss the how spectra and photometry can be used to constrain fireball parameters, describe…
We here discuss a new model of $\gamma$-ray bursts (GRBs) based on differentially rotating strange stars. Strange stars in this model and differentially rotating neutron stars in the Klu\'zniak-Ruderman model can produce extremely…
As the most energetic explosions in the Universe, gamma-ray bursts (GRBs) are commonly believed to be generated by relativistic jets. Recent observational evidence suggests that the jets producing GRBs are likely to have a structured…
I discuss some aspects of the evolution of the standard GRB model, emphasizing various theoretical developments in the last decade, and review the impact of some of the most recent observational discoveries and the new challenges they pose…
Gamma-Ray Bursts (GRBs) are the strongest explosions in the Universe, and are powered by initially ultra-relativistic jets. The angular profile of GRB jets encodes important information about their launching and propagation near the central…
It is by now fairly well established that gamma-ray burst afterglows result from initially relativistic outflows interacting with the medium surrounding the burster and emitting non-thermal radiation ranging from radio to X-rays. However,…
We review some open problems in the physics of afterglows, namely their polarization properties and the existence of dark/faint bursts. Polarization studies yield precious insights in the physical structure and dynamical evolution of GRB…
Gamma-ray burst (GRB) afterglows are likely produced in the shock that is driven as the GRB jet interacts with the external medium. Long-duration GRBs are also associated with powerful supernovae (SNe). We consider the optical and radio…
Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge…
There have been great and rapid progresses in the field of $\gamma$-ray bursts (denoted as GRBs) since BeppoSAX and other telescopes discovered their afterglows in 1997. Here, we will first give a brief review on the observational facts of…
Recent observations suggest that long-duration gamma-ray bursts (GRBs) and their afterglows are produced by highly relativistic jets emitted in core-collapse explosions. The pre-explosive ambient medium provides a natural test for the most…
Gamma-ray bursts and their afterglows are thought to be produced by an ultrarelativistic jet. One of the most important open questions is the outflow composition: the energy may be carried out from the central source either as kinetic…
It is now generally accepted that long gamma-ray bursts are associated with the final evolutionary stages of massive stars. As a consequence, their jets must propagate through the stellar progenitor and break out on their surface, before…
Radio afterglow studies have become an integral part of the study of gamma-ray bursts, providing complementary and sometimes unique diagnostics on GRB explosions, their progenitors, and their environments. This brief review consists of two…
Gamma-ray bursts are thought to be the outcome of a cataclysmic event leading to a relativistically expanding fireball, in which particles are accelerated at shocks and produce nonthermal radiation. We discuss the theoretical predictions of…
The association of at least some long gamma-ray bursts with type Ic supernova explosions has been established beyond reasonable doubt. Theoretically, the challenge is to explain the presence of a light hyper-relativistic flow propagating…