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 $\beta$ observed by the Burst and Transient Source Experiment (BATSE) Large Area Detectors (LAD), we determine the spectral index, $p$, of the electrons' energy distribution. Both the theoretical calculations and numerical simulations of the particle acceleration in relativistic shocks show that $p$ has a universal value $\approx 2.2-2.3$. We show that the observed distribution of $p$ during GRBs is not consistent with a $\delta$-function distribution or an universal $p$ value, with the width of the distribution $\ge$ 0.54. The distributions of $p$ during X-ray afterglows are also investigated and found to be inconsistent with a $\delta$-function distribution. The $p$-distributions in blazars and pulsar wind nebulae are also broad, inconsistent with a $\delta$-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 ‘Witch’s Ladder’

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 ‘Witch’s Ladder’ in a glass case showing ‘Magic and Witchcraft’ at the Pitt Rivers Museum. This ‘retracing’ 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 ‘matter of fact’, its original function is revealed to have been a ‘matter of concern’, enabling this ‘object’ to emerge from its glass case as a ‘thing’ (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 ‘folkloric’ practices of literary folklore