Related papers: Gamma-ray burst early afterglows: reverse shock em…
We present a comprehensive catalog and analysis of broad-band afterglow observations for 103 short-duration gamma-ray bursts (GRBs), comprised of all short GRBs from November 2004 to March 2015 with prompt follow-up observations in the…
GRB afterglow polarization is discussed. We find an observable, up to 10%, polarization, if the magnetic field coherence length grows at about the speed of light after the field is generated at the shock front. Detection of a polarized…
We present extensive radio and millimeter observations of the unusually bright GRB 130427A at z=0.340, spanning 0.67 to 12 days after the burst. Taken in conjunction with detailed multi-band UV, optical, NIR, and X-ray observations we find…
Gamma-ray bursts (GRBs) are luminous stellar explosions characterized by the ejection of relativistic jets. This work proposes a novel paradigm to study these GRB jets. By analyzing the timing information of prompt pulses and X-ray flares,…
We calculate the creation of electron--positron pairs in Gamma-Ray Bursts (GRBs) resulting from the collision between scattered and outward moving gamma-ray photons. The number of pairs exceeds the number of ambient medium electrons…
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…
Gamma-ray bursts (GRBs) are powered by ultra-relativistic jets. The launching sites of these jets are surrounded by dense media, which the jets must cross before they can accelerate and release the high energy emission. Interaction with the…
Despite the pre-Swift expectation that bright optical flashes from reverse shocks would be prevalent in early-time afterglow emission, rapid response observations show this not to be the case. Although very bright at early times, some GRBs…
We calculate the reverse shock (RS) synchrotron emission in the optical and the radio wavelength bands from electron-positron pair enriched gamma-ray burst ejecta with the goal of determining the pair content of GRBs using early time…
We present the second multi-frequency radio detection of a reverse shock in a $\gamma$-ray burst. By combining our extensive radio observations of the Fermi-LAT GRB 160509A at $z = 1.17$ up to $20$ days after the burst with Swift X-ray…
The origins of the magnetic fields that power gamma-ray burst (GRB) afterglow emission are not fully understood. One possible channel for generating these fields involves the pre-conditioning of the circumburst medium: in the early…
Motivated by the detection of very high energy gamma-rays deep in the afterglow emission of a gamma-ray burst, we revisit predictions of the maximum energy to which electrons can be accelerated at a relativistic blast wave. Acceleration at…
Gamma-ray burst (GRB) 120729A was detected by Swift/BAT and Fermi/GBM, and then rapidly observed by Swift/XRT, Swift/UVOT, and ground-based telescopes. It had a single long and smooth \gamma-ray emission pulse, which extends continuously to…
Despite more than fifty years of gamma-ray burst (GRB) observations, several questions regarding the origin of the prompt emission, particularly at high energies, remain unresolved. We present a comprehensive analysis of 35 GRBs observed by…
Gamma-ray Burst (GRB) collimation has been inferred with the observations of achromatic steepening in GRB light curves, known as jet breaks. Identifying a jet break from a GRB afterglow lightcurve allows a measurement of the jet opening…
Gamma-ray bursts (GRBs) are powerful probes of early stars and galaxies, during and potentially even before the era of reionization. Although the number of GRBs identified at z>6 remains small, they provide a unique window on typical…
Recent observations suggest that gamma ray bursts (GRBs) and their afterglows are produced by highly relativistic jets emitted in core collapse supernova explosions (SNe). The result of the event, probably, is not just a compact object plus…
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…
The afterglow emission that follows gamma-ray bursts (GRBs) contains valuable information about the circumburst medium and, therefore, about the GRB progenitor. Theoretical studies of GRB blast waves, however, are often limited to simple…
We constrain the circum-burst medium profile with the rise behavior of the very early afterglow light curves of gamma-ray bursts (GRBs). Using this method, we find a constant and low-density medium profile for GRB 060418 and GRB 060607A,…