Related papers: GRB Jet Beaming Angle Statistics
We report test results of the correlation between time variability and peak luminosity of Gamma-Ray Bursts (GRBs), using a larger sample (32) of GRBs with known redshift than that available to Reichart et al. (2001), and using as…
An observed correlation Ep \propto (E_{iso})^{1/2} extending from Gamma-ray Bursts (GRBs) to X-ray flashes (XRFs) poses problems both for a power-law universal jet model where the energy per solid angle decreases as the inverse square of…
Long-duration gamma-ray bursts (GRBs) are widely believed to be highly-collimated explosions (opening angle theta ~ 1-10 deg). As a result of this beaming factor, the true energy release from a GRB is usually several orders of magnitude…
Studies of GRB host galaxies are crucial to understanding GRBs. However, since they are identified by the superposition in the plane of the sky of a GRB afterglow and a galaxy there is always a possibility that an association represents a…
The composition and radiation mechanism of gamma-ray bursts (GRBs) within jets continue to be hotly debated. Investigating the joint polarimetric and spectral properties is crucial for understanding GRB composition and radiation mechanism.…
Gamma-ray bursts (GRBs) associated with gravitational wave events are, and will likely continue to be, viewed at a larger inclination than GRBs without gravitational wave detections. As demonstrated by the afterglow of GW170817, this…
We extend our calculation of physical parameters of GRB jets by modeling the broadband emission of the afterglows 970508, 980519, 991208, 000926, 000418, and 010222. Together with 990123, 990510, 991216, and 000301c, there are ten…
We report on optical, near-infrared and centimeter radio observations of GRB000418 which allow us to follow the evolution of the afterglow from 2 to 200 days after the gamma-ray burst. In modeling these broad-band data, we find that an…
The GRB980425-SN1998bw association put in severe strain and contradiction the simplest "candle" fireball model for GRBs. We probed that statistically the association is reliable, the energy luminosity and probability puzzles between cosmic…
If gamma ray bursts are highly collimated, radiating into only a small fraction of the sky, the energy requirements of each event may be reduced by several (up to 4 - 6) orders of magnitude, and the event rate increased correspondingly. The…
Starting with models for the compact object merger event rate, the short-duration Gamma-ray Burst (sGRB) luminosity function, and the Swift/BAT detector, we calculate the observed Swift sGRB rate and its uncertainty. Our probabilistic sGRB…
The Collapsar model provides a theoretical framework for the well known association between long gamma-ray bursts (GRBs) and collapsing massive stars. A bipolar relativistic jet, launched at the core of a collapsing star, drills its way…
If the threshold for $e^{-}e^{+}$ pair production depends on an angle between photon momenta, and if the $\gamma$-rays are collimated right in gamma-ray burst (GRB) source then another solution of the compactness problem is possible. The…
In several GRBs afterglows, rapid temporal decay is observed which is inconsistent with spherical (isotropic) blast-wave models. In particular, GRB 980519 had the most rapidly fading of the well-documented GRB afterglows, with t^{-2.05\pm…
Three different methods of measuring cosmology with gamma-ray bursts (GRBs) have been proposed since a relation between the $\gamma$-ray energy $E_{\gamma} $ of a GRB jet and the peak energy $E_p$ of the $\nu F_{\nu}$ spectrum in the burst…
There are several lines of evidence indicating that the ultra-relativistic outflows powering gamma-ray bursts (GRBs) are collimated into narrow jets. However, these are indirect, and the jet structure is rather poorly constrained. What is…
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…
Evidence of polarized $\gamma$-ray emission ($>$ 50 keV) from Gamma-Ray Bursts (GRBs) has been accumulated in recent years. Measurements have been reported with levels in the range of 30-80\%, typically with limited statistical…
The two leading models for the structure of GRB jets are the uniform jet model and the universal structured jet (USJ) model. In the latter, all GRB jets are intrinsically identical and the energy per solid angle drops as the inverse square…
We investigate the shape of the jet break in within-beam gamma-ray burst (GRB) optical afterglows for various lateral jet structure profiles. We consider cases with and without lateral spreading and a range of inclinations within the jet…