Related papers: Gamma-ray burst early optical afterglows: implicat…
The prompt optical emission that arrives with gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions…
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…
Most long gamma-ray bursts (GRBs) exhibit afterglows broadly consistent with external forward-shock emission, typically described by smooth broken power-law decays in the multiband light curve. However, a minority of well-sampled GRBs…
Based on the refined dynamical model proposed by us earlier for beamed $\gamma$-ray burst ejecta, we carry out detailed numerical procedure to study those $\gamma$-ray bursts with rapidly fading afterglows (i.e., $\sim t^{-2}$). It is found…
The long gamma-ray burst GRB 161017A was detected by Fermi and Swift, and its afterglow was observed by the MITSuME 50-cm optical telescope promptly about 50 s after the burst. Early optical observations revealed that the optical lightcurve…
One of the most energetic gamma-ray bursts GRB 110731A, was observed from optical to GeV energy range by Fermi and Swift Observatories, and by the MOA and GROND optical telescopes. The multiwavelength observations over different epochs…
The detection of optical re-brightenings and X-ray plateaus in the afterglows of gamma-ray bursts (GRBs) challenges the generic external shock model. Recently, we have developed a numerical method to calculate the dynamic of the system…
(Abridged) The Swift X-Ray Telescope (XRT) reveals some interesting features of early X-ray afterglows, including a distinct rapidly decaying component preceding the conventional afterglow component in many sources, a shallow decay…
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…
We present results of Swift optical, UV and X-ray observations of the afterglow of GRB 050801. The source is visible over the full optical, UV and X-ray energy range of the Swift UVOT and XRT instruments.Both optical and X-ray lightcurves…
We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT, UVOT data and multi-color optical imaging from ten ground-based telescopes. GRB 061126 was a long burst (T_90=191 s) with four…
In the internal shock scenario for GRBs we expect some fraction of the energy of the burst to be carried by slow moving shells that were ejected at late times. These slow shells collide with faster moving outer shells when the outer shells…
We present optical and near-infrared photometric observations of GRB 191016 with the COATLI, DDOTI and RATIR ground-based telescopes over the first three nights. We present the temporal evolution of the optical afterglow and describe 5…
We report on the multiwavelength observations of the bright, long gamma-ray burst \GRB, by the \Fermi and \Swift observatories, and by the MOA and GROND optical telescopes. The analysis of the prompt phase reveals that \GRB shares many…
We describe our attempt to determine if gamma-ray burst (GRB) and afterglow emissions could both arise in external shocks for simple GRBs--bursts consisting of just a few peaks in their lightcurves. We calculate peak flux and peak frequency…
The optical emission of GRB 110205A is distinguished by two flares. In this work we examine two possible scenarios for the optical afterglow emission. In the first scenario, the first optical flare is the reverse shock emission of the main…
The reverse shock (RS) model is generally introduced to interpret the optical afterglows with the rapid rising and decaying, such as the early optical afterglow of GRB 990123 (which is also called optical flash). In this paper, we collected…
Gamma-ray bursts (GRBs) are the most luminous explosions in the universe, yet the nature and physical properties of their energy sources are far from understood. Very important clues, however, can be inferred by studying the afterglows of…
The afterglow of a gamma-ray burst (GRB) has been widely argued to arise from the interaction of a relativistic outflow with its ambient medium. During such an interaction, a pair of shocks are generated: a forward shock that propagates…
We study the early afterglows of gamma-ray bursts produced by geometrically thick fireballs, following the development of the external shock as energy is continually supplied to the shocked material. We study the dependence of the early…