Related papers: GRB jet structure and the jet break
The afterglow of GRB 050401 presents several novel and interesting features : [1] An initially faster decay in optical band than in X-rays. [2] A break in the X-ray light curve after $\sim$ 0.06 day with an unusual slope after the break.…
We present radio, optical/NIR, and X-ray observations of the afterglow of the short-duration 130603B, and uncover a break in the radio and optical bands at 0.5 d after the burst, best explained as a jet break with an inferred jet opening…
Gamma-ray bursts are expected to be generated by structured jets, whose profiles significantly impact their afterglow emission. Previously, we developed a numerical code jetsimpy, to model the afterglow of jets with arbitrary angular…
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…
We report the results of the \chandra observations of the \swift-discovered short Gamma-Ray Burst GRB 050724. \chandra observed this burst twice, about two days after the burst and a second time three weeks later. The first \chandra…
We determine the basic physical characteristics of eight Gamma-Ray Bursts -- 980519, 990123, 990510, 991028, 991216, 000301c, 000926 and 010222 -- by modelling the broadband emission of their afterglows. We find that the burst kinetic…
In Budai et al. (2020) we argued that angular non-stationarities of gamma-ray burst (GRB) jets can result in a statistical connection between the angle values deduced from jet break times and the variabilities of prompt light curves. The…
In the past few years, the improved sensitivity and cadence of wide-field optical surveys have enabled the discovery of several afterglows without associated detected gamma-ray bursts (GRBs). We present the identification, observations, and…
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…
We present X-ray observations of the afterglow of GRB000926 performed around and after the break observed in the optical light curve two days after the burst. The steep X-ray light curve observed around the break confirms the presence of…
The energy requirements of gamma ray bursts have in past been poorly constrained because of three major uncertainties: The distances to bursts, the degree of burst beaming, and the efficiency of gamma ray production. The first of these has…
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…
The X-ray afterglows (AGs) of Gamma-Ray Bursts (GRBs) and X-Ray Flashes (XRFs) have, after the fast decline phase of their prompt emission, a temporal behaviour varying between two extremes. A large fraction of these AGs has a 'canonical'…
A number of gamma-ray bursts (GRBs) exhibit the late simultaneous bumps in their optical and Xray afterglows around the jet break. Its origin is unclear. Based on the following two facts, we suggest that this feature may sound a transition…
Two-component jets are frequently invoked to explain complex features in gamma-ray burst (GRB) afterglows, such as late-time rebrightening and chromatic breaks. While many studies fit these models to individual events, a systematic…
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 nearest GRB 170817A provided an opportunity to probe the angular structure of the jet of this short gamma-ray burst (SGRB), by using its off-axis observed afterglow emission. It is investigated that whether the afterglow-constrained jet…
Follow-up observations of large numbers of gamma-ray burst (GRB) afterglows, facilitated by the Swift satellite, have produced a large sample of spectral energy distributions and light curves, from which the basic micro- and macrophysical…
Due to relativistic bulk motion, the structure and orientation of gamma-ray burst jets have a fundamental role in determining how they appear. The recent discovery of the GW170817 binary neutron star merger and the associated GRB boosted…
The jet opening angle theta_jet and the bulk Lorentz factor Gamma_0 are crucial parameters for the computation of the energetics of Gamma Ray Bursts (GRBs). From the ~30 GRBs with measured theta_jet or Gamma_0 it is known that: (i) the real…