13 research outputs found
No Universality for Electron's Power-Law Index (p) in Gamma-Ray Bursts and Other Relativistic Sources
The Gamma-Ray Burst (GRB) prompt emission is believed to be from highly
relativistic electrons accelerated in relativistic shocks. From the GRB
high-energy power-law spectral indices observed by the Burst and
Transient Source Experiment (BATSE) Large Area Detectors (LAD), we determine
the spectral index, , of the electrons' energy distribution. Both the
theoretical calculations and numerical simulations of the particle acceleration
in relativistic shocks show that has a universal value .
We show that the observed distribution of during GRBs is not consistent
with a -function distribution or an universal value, with the width
of the distribution 0.54. The distributions of during X-ray
afterglows are also investigated and found to be inconsistent with a
-function distribution. The -distributions in blazars and pulsar
wind nebulae are also broad, inconsistent with a -function
distribution.Comment: 19 pages, 6 figures, a larger Swift afterglow sample include
Using X-Ray Polarimetry to Probe the Physics of Black Holes and Neutron Stars
This white paper highlights compact object and fundamental physics science opportunities afforded by high-throughput broadband (0.1-60 keV) X-ray polarization observations. The polarimetric observations can reveal the inner workings of high-energy sources, and allow us to test physical laws in the extreme conditions close to compact objects
A case re-opened: the science and folklore of a âWitchâs Ladderâ
This article retraces the process by which a feathered rope, discovered in the roof of a house in Somerset, came to be displayed as a âWitchâs Ladderâ in a glass case showing âMagic and Witchcraftâ at the Pitt Rivers Museum. This âretracingâ has revealed a set of alternative associations that the feathered rope has had: with other museum objects and written documents, as well as with a range of people. Although presented in the museum as a âmatter of factâ, its original function is revealed to have been a âmatter of concernâ, enabling this âobjectâ to emerge from its glass case as a âthingâ (Latour). Retracing its network and the historical process by which it became a museum object has meant engaging with the scientific ambitions of E.B.Tylor and his notions of independent corroborating evidence, as well as with the more âfolkloricâ practices of literary folklore