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 X-ray, optical, near-infrared and/or radio bands. These afterglow observations have uncovered 71 X-ray detections, 30 optical/NIR detections, and 4 radio detecti...

A new method to estimate the Doppler beaming factor of relativistic large-scale jet regions is presented. It is based on multiwaveband fitting to radio-to-X-ray continua with synchrotron spectrum models. Combining our method with available observational data of proper motions, we derive the intrinsic velocity as well as the viewing angles to the line of sight for eight knotty regions down the M...

In this paper I put forward a model in which GRB980425 is both associated with SN1998bw and is also a standard canonical (long; ∼ seconds) gamma-ray burst. Herein it is argued that if gamma-ray bursts are relativistic jets with the fastest moving material at the core, then the range of observed jet inclinations to the line-of-sight produces a range in the observed properties of GRBs, i.e. the l...

Power beaming from ground-based systems to space-based platforms has been proposed by a number of researchers as a means of delivering energy to orbiting satellites and stations. This paper considers the use of a seeded high-gain highefficiency Free-Electron Laser (FEL) amplifier based on a conventional linac as the source for power beaming. While the wall-plug efficiency of a single pass FEL i...

Most of gamma-ray bursts (GRBs) models have predicted that the intrinsic isotropic energy is limited to below ∼ 10ergs. Recently claimed high redshifts, correlation with supernovae, and connection to the cosmic star formation activity point to a different energy requirement and source evolution history possibly with strong beaming. We study the effects of the beaming-induced luminosity function...

We present a freely available XSPEC model for the modulations seen in the long-term light curves of multiple ultraluminous X-ray sources (ULXs). By incorporating the physics of multiple electron scatterings (ray traced with a Monte-Carlo routine), we go beyond analytical predictions and show that the geometrical beaming of radiation in the conical outflow can be more than a factor of 100 for op...

The number of orphan radio afterglows associated with γ-ray bursts (GRBs) that should be detected by a flux limited radio survey, is calculated. It is shown that for jetted GRBs this number is smaller for smaller jet opening angle θ, contrary to naive expectation. For a beaming factor f b ≡ (θ/2) ≃ 500, roughly the value inferred by Frail et al. (2001) from analysis of afterglow light curves, w...

For a sample of 51 blazars with extensive optical polarization data, we used circular statistics to calculate the scatter among the polarization position angles for each object. We found that this scatter is correlated with the radio core dominance. We compared this relationship with the predictions of a simple transverse shock model. The result suggests that blazar jets are likely to cover a w...