The Contribution of Fermi Gamma-Ray Pulsars to the local Flux of Cosmic-Ray Electrons and Positrons

We analyze the contribution of gamma-ray pulsars from the first Fermi-Large Area Telescope (LAT) catalogue to the local flux of cosmic-ray electrons and positrons (e+e-). We present new distance estimates for all Fermi gamma-ray pulsars, based on the measured gamma-ray flux and pulse shape. We then estimate the contribution of gamma-ray pulsars to the local e+e- flux, in the context of a simple model for the pulsar e+e- emission. We find that 10 of the Fermi pulsars potentially contribute significantly to the measured e+e- flux in the energy range between 100 GeV and 1 TeV. Of the 10 pulsars, 2 are old EGRET gamma-ray pulsars, 2 pulsars were discovered with radio ephemerides, and 6 were discovered with the Fermi pulsar blind-search campaign. We argue that known radio pulsars fall in regions of parameter space where the e+e- contribution is predicted to be typically much smaller than from those regions where Fermi-LAT pulsars exist. However, comparing the Fermi gamma-ray flux sensitivity to the regions of pulsar parameter space where a significant e+e- contribution is predicted, we find that a few known radio pulsars that have not yet been detected by Fermi can also significantly contribute to the local e+e- flux if (i) they are closer than 2 kpc, and if (ii) they have a characteristic age on the order of one mega-year.Comment: 21 pages, 6 figures, accepted for publication in JCA

Associations of Very High Energy Gamma-Ray Sources Discovered by H.E.S.S. with Pulsar Wind Nebulae

The H.E.S.S. array of imaging Cherenkov telescopes has discovered a number of previously unknown gamma-ray sources in the very high energy (VHE) domain above 100 GeV. The good angular resolution of H.E.S.S. (~0.1 degree per event), as well as its sensitivity (a few percent of the Crab Nebula flux) and wide 5-degree field of view, allow a much better constrained search for counterparts in comparison to previous instruments. In several cases, the association of the VHE sources revealed by H.E.S.S. with pulsar wind nebulae (PWNe) is supported by a combination of positional and morphological evidence, multi-wavelength observations, and plausible PWN model parameters. These include the plerions in the composite supernova remnants G 0.9+0.1 and MSH 15-52, the recently discovered Vela X nebula, two new sources in the Kookaburra complex, and the association of HESS J1825-137 with PSR B1823-13. The properties of these better-established associations are reviewed. A number of other sources discovered by H.E.S.S. are located near high spin-down power pulsars, but the evidence for association is less complete. These possible associations are also discussed, in the context of the available multi-wavelength data and plausible PWN scenarios.Comment: 5 pages, to appear in Astrophysics and Space Science (proceedings of "The Multi-Messenger Approach to High-Energy Gamma-Ray Sources"

Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release

Does ISO 9000 work?

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Systemic consumer production Lessons from family therapy

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Marketing communication theory What do the texts teach our students?

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The co-ordinated management of meaning A new technology for consumer researchers

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The theory and practice of customer bonding An IMP perspective

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Reconstrucción tridimensional de la velocidad del viento solar mediante tomografía Lyman-α

La determinación de la estructura termodinámica tridimensional (3D) de la corona solar por medios observacionales es de gran importancia para avanzar en la comprensión de los mecanismos físicos responsables del calentamiento coronal, así como para el desarrollo de modelos magnetohidrodinámicos (MHD) globales de la corona. Orientada a este fin, la tomografia solar rotacional utiliza series temporales de imágenes de la corona solar en luz visible (LV) y extremo ultravioleta, para determinar la distribución 3D de la densidad y temperatura electrónica de la corona solar. En este trabajo presentamos una nueva técnica tomográfica que, basada en imágenes coronales en Lyman-α y LV, permite la reconstrucción 3D del factor de atenuación Doppler Lyman-α. Este resultado, en combinación con un modelo global del campo magnético, permite reconstruir la distribución 3D de la velocidad del viento solar. El coronógrafo Metis a bordo de la misión espacial Solar Orbiter, que recientemente entró en operación, toma imágenes en ambos rangos espectrales, lo que permitirá aplicar la técnica por primera vez. Presentamos la metodología y resultados preliminares basados en simulaciones numéricas.Determination of the three-dimensional (3D) thermodynamic structure of the solar corona by observational means is of great importance to advance the understanding of the physical mechanisms responsible for coronal heating, as well as for the development of global magnetohydrodynamic (MHD) models of the corona. Oriented to this end, solar rotational tomography makes use of time series of images of the solar corona in visible light (VL) and in extreme ultraviolet, to determine the 3D distribution of the electron density and temperature of the solar corona. In this work we present a new tomographic technique that, based on coronal images in Lyman-α and VL, allows 3D reconstruction of the Lyman-α Doppler dimming term. In combination with a global model of the magnetic field, this allows 3D reconstruction of the solar wind speed. The recently operational Metis coronagraph, aboard the Solar Orbiter space mission, takes images in both spectral ranges, which will allow to apply the technique for the first time. We describe the methodology and present preliminary results based on numerical simulations.Asociación Argentina de Astronomí