Heat resistant protective hand covering

The heat resistant, protective glove is made up of first and second shell sections which define a palm side and a backside, respectively. The first shell section is made of a twill wave fabric of a temperature-resistant aromatic polyamide fiber. The second shell section is made of a knitted fabric of a temperature-resistant aromatic polyamide fiber. The first and second shell sections are secured to one another, e.g., by sewing, to provide the desired glove configuration and an opening for insertion of the wearer's hand. The protective glove also includes a first liner section which is secured to and overlies the inner surface of the first shell section and is made of a felt fabric of a temperature-resistant aromatic polyamide fiber and has a flame resistant, elastomenic coating on the surface facing and overlying the inner surface of the first shell section

Discovery of kHz Fluctuations in Centaurus X-3: Evidence for Photon Bubble Oscillations (PBO) and Turbulence in a High Mass X-ray Binary Pulsar

We report the discovery of kHz fluctuations, including quasi-periodic oscillations (QPO) at ~330 Hz and ~760 Hz and a broadband kHz continuum in the power density spectrum of the high mass X-ray binary pulsar Centaurus X-3. These observations of Cen X-3 were carried out with the Rossi X-ray Timing Explorer (RXTE). The fluctuation spectrum is flat from mHz to a few Hz, then steepens to $f^{-2}$ behavior between a few Hz and ~100 Hz. Above a hundred Hz, the spectrum shows the QPO features, plus a flat continuum extending to ~1200 Hz and then falling out to ~1800 Hz. These results, which required the co-adding three days of observations of Cen X-3, are at least as fast as the fastest known variations in X-ray emission from an accreting compact object (kHz QPO in LMXB sources) and probably faster since extension to ~1800 Hz is indicated by the most likely parameterization of the data. Multi-dimensional radiation hydrodynamics simulations of optically thick plasma flow onto the magnetic poles of an accreting neutron star show that the fluctuations at frequencies above 100 Hz are consistent with photon bubble turbulence and oscillations (PBO) previously predicted to be observable in this source. For a polar cap opening angle of 0.25 radians, we show that the spectral form above 100 Hz is reproduced by the simulations, including the frequencies of the QPO and the relative power in the QPO and the kHz continuum. This has resulted in the first model-dependent measurement of the polar cap size of an X-ray pulsar.Comment: received ApJ: April 1, 1999 accepted ApJ: September 1, 199

Heat resistant protective hand covering

A heat-resistant aromatic polyamide fiber is described. The outer surface of the shell is coated with a fire-resistant elastomer and liner. Generally conforming and secured to the shell and disposed inwardly of the shell, the liner is made of a felt fabric of temperature-resistant aromatic polymide fiber

Relativistic Particle Acceleration in a Folded Current Sheet

Two-dimensional particle simulations of a relativistic Harris current sheet of pair plasmashave demonstrated that the system is unstable to the relativistic drift kink instability (RDKI) and that a new kind of acceleration process takes place in the deformed current sheet. This process contributes to the generation of non-thermal particles and contributes to the fast magnetic dissipation in the current sheet structure. The acceleration mechanism and a brief comparison with relativistic magnetic reconnection are presented.Comment: 11 preprint pages, including 3 .eps figure

A Tale of Two Current Sheets

I outline a new model of particle acceleration in the current sheet separating the closed from the open field lines in the force-free model of pulsar magnetospheres, based on reconnection at the light cylinder and "auroral" acceleration occurring in the return current channel that connects the light cylinder to the neutron star surface. I discuss recent studies of Pulsar Wind Nebulae, which find that pair outflow rates in excess of those predicted by existing theories of pair creation occur, and use those results to point out that dissipation of the magnetic field in a pulsar's wind upstream of the termination shock is restored to life as a viable model for the solution of the "$\sigma$" problem as a consequence of the lower wind 4-velocity implied by the larger mass loading.Comment: 17 pages, 6 figures, Invited Review, Proceedings of the "ICREA Workshop on The High-Energy Emission from Pulsars and their Systems", Sant Cugat, Spain, April 12-16, 201

Can the anomalous X-ray pulsars be powered by accretion?

The nature of the 5-12 s "anomalous" X-ray pulsars remains a mystery. Among the models that have been proposed to explain the properties of AXPs, the most likely ones are: (1) isolated accreting neutron stars evolved from the Thorne-\.{Z}ytkow objects due to complete spiral-in during the common envelope evolution of high-mass X-ray binaries, and (2) magnetars, which are neutron stars with ultra-high ($\sim 10^{14}-10^{15}$ G) surface magnetic fields. We have critically examined the predicted change of neutron star's spin in the accretion model, and found that it is unable to account for the steady spin-down observed in AXPs. A simple analysis also shows that any accretion disk around an isolated neutron star has extremely limited lifetime. A more promising explanation for such objects is the magnetar model.Comment: 9 pages, accepted for publication in Ap

Drifting subpulses and inner acceleration regions in radio pulsars

The classical vacuum gap model of Ruderman & Sutherland, in which spark-associated subbeams of subpulse emission circulate around the magnetic axis due to the EB drift, provides a natural and plausible physical mechanism of the subpulse drift phenomenon. Recent progress in the analysis of drifting subpulses in pulsars has provided a strong support to this model by revealing a number of subbeams circulating around the magnetic axis in a manner compatible with theoretical predictions. However, a more detailed analysis revealed that the circulation speed in a pure vacuum gap is too high when compared with observations. Moreover, some pulsars demonstrate significant time variations of the drift rate, including a change of the apparent drift direction, which is obviously inconsistent with the EB drift scenario in a pure vacuum gap. We resolved these discrepancies by considering a partial flow of iron ions from the positively charged polar cap, coexisting with the production of outflowing electron-positron plasmas. By fitting the observationally deduced drift-rates to the theoretical values, we managed to estimate polar cap surface temperatures in a number of pulsars. The estimated surface temperatures correspond to a small charge depletion of the order of a few percent of the corotational charge density. We also argue that if the thermionic electron outflow from the surface of a negatively charged polar cap is slightly below the Goldreich-Julian density, then the resulting small charge depletion will have similar consequences as in the case of the ions outflow. We thus believe that the sparking discharge of a partially shielded acceleration potential drop occurs in all pulsars, with both positively (``pulsars'') and negatively (``anti-pulsars'') charged polar caps

Magnetic Confinement, MHD Waves, and Smooth Line Profiles in AGN

In this paper, we show that if the broad line region clouds are in approximate energy equipartition between the magnetic field and gravity, as hypothesized by Rees, there will be a significant effect on the shape and smoothness of broad emission line profiles in active galactic nuclei. Line widths of contributing clouds or flow elements are much wider than their thermal widths, due to the presence of non-dissipative MHD waves, and their collective contribution produce emission line profiles broader and smoother than would be expected if a magnetic field were not present. As an illustration, a simple model of isotropically emitting clouds, normally distributed in velocity, is used to show that smoothness can be achieved for less than 80,000 clouds and may even be as low as a few hundred. We conclude that magnetic confinement has far reaching consequences for observing and modeling active galactic nuclei.Comment: to appear in MNRA

INTEGRAL observations of TeV plerions

Amongst the sources seen in very high gamma-rays several are associated with Pulsar Wind Nebulae (``TeV plerions''). The study of hard X-ray/soft gamma-ray emission is providing an important insight into the energetic particle population present in these objects. The unpulsed emission from pulsar/pulsar wind nebula systems in the energy range accessible to the INTEGRAL satellite is mainly synchrotron emission from energetic and fast cooling electrons close to their acceleration site. Our analyses of public INTEGRAL data of known TeV plerions detected by ground based Cherenkov telescopes indicate a deeper link between these TeV plerions and INTEGRAL detected pulsar wind nebulae. The newly discovered TeV plerion in the northern wing of the Kookaburra region (G313.3+0.6 powered by the middle aged PSR J1420-6048) is found to have a previously unknown INTEGRAL counterpart which is besides the Vela pulsar the only middle aged pulsar detected with INTEGRAL. We do not find an INTEGRAL counterpart of the TeV plerion associated with the X-ray PWN ``Rabbit'' G313.3+0.1 which is possibly powered by a young pulsar.Comment: 4 pages, 6 figures, proceedings of conference "The Multi-Messenger Approach to High-Energy Gamma-ray Sources" Barcelona/Spain (2006