Related papers: Evidences for two Gamma-Ray Burst afterglow emissi…
We present a set of seventeen Gamma-Ray Bursts (GRBs) with known redshifts and X-ray afterglow emission. We apply cosmological corrections in order to compare their fluxes normalized at a redshift of 1. Two classes of GRB can be defined…
The recent detection of delayed X-ray and optical emission, ``afterglow,'' associated with gamma-ray bursts (GRBs) supports models, where the bursts are produced by relativistic expanding blastwaves, ``fireballs,'' at cosmological…
The 'jet-break' in the X-ray afterglow of gamma ray bursts (GRBs) appears to be correlated to other properties of the X-ray afterglow and the prompt gamma ray emission, but the correlations are at odds with those predicted by the conical…
The discovery of X-ray, optical and radio afterglows of GRBs provides an important tool for understanding these sources. Most current models envisage GRB as arising in a cataclysmic stellar event leading to a relativistically expanding…
We investigate the clustering of afterglow light curves observed at X-ray and optical wavelengths. We have constructed a sample of 61 bursts with known distance and X-ray afterglow. GRB sources can be divided in three classes, namely…
The detection of x-ray afterglows of gamma-ray burst (GRB) sources has enabled the optical discovery that GRBs are at cosmological distances, which confirms that the enormous luminosities required must produce a relativistically expanding…
A GRB afterglow has been commonly thought to be due to continuous deceleration of a postburst fireball. Many analytical models have made simplifications for deceleration dynamics of the fireball and its radiation property, although they are…
The detection of delayed X-ray, optical and radio emission, "afterglow", associated with $\gamma$-ray bursts (GRBs) is consistent with fireball models, where the emission are produced by relativistic expanding blast wave, driven by…
A systematical study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts (B-GRBs and D-GRBs) observed by Swift has been presented. Our sample includes 25 GRBs. Among them 13 are B-GRBs and 12 are D-GRBs. Our…
We consider possible interpretations of the recently detected X- ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray…
I review gamma-ray burst optical/multiwavelength afterglow observations since 1997, when the first counterparts to GRBs were discovered. I discuss what we have learned from multiwavelength observations of GRB afterglows in relation to the…
The afterglow emission has become the main stream of Gamma-Ray burst research since its discovery three years ago. With the distance-scale enigma solved, the study of the late-time GRB emission is now the most promising approach to disclose…
The afterglow of a gamma-ray burst (GRB) is commonly thought to be due to continuous deceleration of a relativistically expanding fireball in the surrounding medium. Assuming that the expansion of the fireball is adiabatic and that the…
Four years after the launch the Swift satellite the nature of the Gamma Ray Bursts (GRBs) broadband afterglow behaviour is still an open issue ad the standard external shock fireball models cannot easily explain the puzzling combined…
The Gamma-Ray Bursts - GRBs are one of the most energetic astronomical events in the universe that have not yet an adequate explanation of what kind of mechanism is carried out. This question motivates the astronomical community to do…
Observational evidence of iron absorption and emission lines in X-ray spectra of Gamma-Ray Bursts is quite compelling. I will briefly review the results, summarize different models and describe the connection with massive progenitors in…
We study an extensive sample of 87 GRBs for which there are well sampled and simultaneous optical and X-ray light-curves. We extract the cleanest possible signal of the afterglow component, and compare the temporal behaviors of the X-ray…
This paper presents the theoretical basis of the fireball/blast wave model, and some implications of recent results on GRB source models and cosmic-ray production from GRBs. BATSE observations of the prompt gamma-ray luminous phase, and…
Gamma-ray bursts (GRBs) are thought to result from the interaction of an extremely relativistic outflow interacting with a small amount of material surrounding the site of the explosion. Multi-wavelength observations covering the gamma-ray…
The optical and X-ray light-curves of long Gamma Ray Bursts (GRBs) often show a complex evolution and in most cases do not track each other. This behaviour can not be easily explained by the simplest standard afterglow models. A possible…