Related papers: Afterglow Lightcurves from Misaligned Structured J…
Our knowledge of the intrinsic properties of short duration Gamma-Ray Bursts has relied, so far, only upon a few cases for which the estimate of the distance and an extended, multiwavelength monitoring of the afterglow have been obtained.…
Gamma-ray burst afterglows arise from relativistic collisionless shocks in which the postshock tangled magnetic field $\vec{B}$ is produced by the two-stream and/or Weibel instabilities on plasma skin-depth scales $(c/\omega_p)$. The field…
We investigate analytically the effect of an anisotropic distribution of the kinetic energy within a relativistic fireball on the decay of the afterglow emission, focusing on axially symmetric fireballs with a uniform core and a power-law…
The most interesting current open question in the theory of GRB afterglow is the propagation of jetted afterglows during the sideway expansion phase. Recent numerical simulations show hydrodynamic behavior that differs from the one…
In this paper, within the popular internal shock scenario of GRBs, we calculate the early optical afterglow lightcurves of a neutron-fed GRB fireball for different assumed neutron fractions in the fireball and for both ISM- and…
We use data on the image size of the radio afterglow of GRB 030329 (Taylor et al. 2004) to constrain the physical parameters of this explosion. Together with the observed broad band spectrum, this data over-constrains the physical…
Among the large variety of astrophysical sources that we can observe, gamma-ray bursts (GRBs) are the most energetic of the whole Universe. The definition of a general picture describing the physics behind GRBs has always been a compelling…
(Abridged) We present the earliest optical observations of the optical counterpart to the GRB 010222, obtained with the FLWO 1.2-m telescope in UBVRI passbands, starting 3.64 hours after the burst. We also present late R-band observations…
Extragalactic fast X-ray transients (FXTs) are short-duration ($\sim$ ks) X-ray flashes of unknown origin, potentially arising from binary neutron star mergers. We investigate the possible link between FXTs and the afterglows of off-axis…
Gamma-ray bursts (GRBs) at high redshifts are expected to be gravitationally lensed by objects of different mass scales. Besides a single recent claim, no lensed GRB has been detected so far by using the gamma-ray data only. In this paper,…
X-ray light curves of gamma-ray burst (GRB) afterglows exhibit various features, with the shallow decay phase being particularly puzzling. While some studies report absence of the X-ray shallow decay for hyper-energetic GRBs, recently…
In gamma-ray burst research it is quite common to fit the afterglow light curves with a broken power law to interpret the data. We apply this method to a computer simulated population of afterglows and find systematic differences between…
We carry out a numerical hydrodynamical modeling for the evolution of a relativistic collimated outflow, as it interacts with the surrounding medium, and calculate the light-curve resulting from synchrotron emission of the shocked fluid.…
The simplest model of the afterglows of the gamma-ray bursts (GRBs) envisions a spherical blast wave with a power-law distribution of electron energy above some cutoff running into a constant density medium. A refinement involves a narrow…
We present multicolor optical observations of the nearby (z=0.1685) GRB 030329 obtained with the same instrumentation over a time period of 6 hours for a total of an unprecedented 475 quasi-simultaneous BVR observations. The achromatic…
Gamma-ray burst (GRB) afterglows are well described by synchrotron emission originating from the interaction between a relativistic blast wave and the external medium surrounding the GRB progenitor. We introduce a code to reconstruct…
Aims: GRB 050502B is well known for the very bright flare displayed in its X-ray light curve. Despite extensive studies, however, the optical light curve has never been discussed and its redshift is unconstrained. Possible correlations…
According to the fireball model gamma-ray burst (GRB) afterglows are the result of a shock pushed into the surrounding medium by an extremely relativistic outflow from the GRB. By modeling the broadband spectrum, ranging from X-ray to radio…
This paper investigates GRB 050802, one of the best examples of a it Swift gamma-ray burst afterglow that shows a break in the X-ray lightcurve, while the optical counterpart decays as a single power-law. This burst has an optically bright…
Early rebrightenings at a post-burst time of 10^2 - 10^4 s have been observed in the afterglows of some gamma-ray bursts (GRBs). Unlike X-ray flares, these rebrightenings usually last for a relatively long period. The continuous energy…