Modelling the Evolution of Pulsar Wind Nebulae PDF Download

Author: Michael Johannes Vorster
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 168

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Author: Michael Johannes Vorster
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 0

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Book Description
Composite supernova remnants -- Morphological evolution -- Hydrodynamic -- Kinematic magnetic field -- Pulsar wind nebulae -- Particle evolution models -- Fokker-Planck transport equation -- Spherically-symmetric -- Axisymmetric -- Diffusion -- Drift -- Energy losses -- Saamgestelde supernova-oorblyfsels -- Morfologiese evolusie -- Hidrodinamiese -- Kinematiese magneetveld pulsarwindnewels -- Deeltjie evolusiemodelle -- Fokker-Planck transport vergelyking -- Sferies-simmetries -- Aksiaal-simmetries -- Diffusie -- Dryf -- Energie verliese.

Author: Diego F. Torres
Publisher:
ISBN: 9783319630328
Category : Astronomy
Languages : en
Pages : 313

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Author: Sebastian Meßlinger
Publisher:
ISBN:
Category :
Languages : en
Pages : 34

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Author: David Carreto Fidalgo
Publisher: Springer
ISBN: 3030241947
Category : Science
Languages : en
Pages : 208

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This book reports on the extraordinary observation of TeV gamma rays from the Crab Pulsar, the most energetic light ever detected from this type of object. It presents detailed information on the painstaking analysis of the unprecedentedly large dataset from the MAGIC telescopes, and comprehensively discusses the implications of pulsed TeV gamma rays for state-of-the-art pulsar emission models. Using these results, the book subsequently explores new testing methodologies for Lorentz Invariance Violation, in terms of a wavelength-dependent speed of light. The book also covers an updated search for Very-High-Energy (VHE), >100 GeV, emissions from millisecond pulsars using the Large Area Telescope on board the Fermi satellite, as well as a study on the promising Pulsar Wind Nebula candidate PSR J0631. The observation of VHE gamma rays is essential to studying the non-thermal sources of radiation in our Universe. Rotating neutron stars, also known as pulsars, are an extreme source class known to emit VHE gamma rays. However, to date only two pulsars have been detected with emissions above 100 GeV, and our understanding of their emission mechanism is still lacking.

Author:
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Category :
Languages : en
Pages : 0

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Pulsars -- Pulsar wind nebulae -- Supernova remnants -- Gamma rays -- Non-thermal radiation mechanisms -- Neutron stars -- X-rays -- Multi-wavelength astronomy -- Astroparticle physics -- Numerical methods.

Author: Albert Adam Van Etten
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Energetic particles streaming out from rapidly spinning neutron stars radiate across the electromagnetic spectrum, creating a pulsar wind nebula (PWN). Many PWNe are spatially resolved in the radio, X-ray, and even gamma-ray wavebands, and thereby provide an excellent laboratory to study not only pulsar winds and dynamics, but also shock processes, magnetic field evolution, and particle transport. Single-zone spectral energy distribution (SED) models have long been used to study the global properties of PWNe, but to fully take advantage of high spatial resolution data one must move beyond these simple models. Supported by multiple X-ray PWN observations, we describe multi-zone time-dependent SED model fitting, with particular emphasis on the spatial variations within nebulae. The SED model constrains the wind velocity profile, magnetic field profile, age and spin-down history of the central pulsar, and the PWN injection spectrum. These constraints are of great value to the study of the gamma-ray pulsar population, and to investigations of particle acceleration and the cosmic ray spectrum. The large size of many PWNe in the very high energy gamma-ray (TeV) regime is indicative of significant particle transport over the pulsar lifetime, and in the case study of HESS J1825-137 we find that rapid diffusion of high energy particles is required to match the multi-wavelength data.

Author: Steven Brett McArthur
Publisher:
ISBN:
Category :
Languages : en
Pages : 302

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Book Description
Observations of TeV gamma rays enable investigation of extreme, high-energy astrophysical environments. Of the identied TeV sources within the Galaxy, the largest number are pulsar wind nebulae (PWNe), formed by the shocked wind of relativistic leptons emitted by a pulsar and conned by the surrounding medium, with broadband emission arising from synchrotron and inverse Compton mechanisms. PWNe exhibit a wide range of morphologies as a result of a complex evolution, depending on the properties of the parent pulsar and conning medium. This work describes the discovery of gamma-ray emission from the PWN within the supernova remnant (SNR) CTA 1 by the VERITAS telescope array. By imaging the Cherenkov light from gamma-ray induced atmospheric showers, VERITAS revealed an extended TeV nebula surrounding the pulsar PSR J0007+7303. Comparison of the observed properties with known PWN, along with a one-zone model, suggests a recent interaction with the SNR reverse shock and allows for an estimate of the average nebular magnetic eld strength. No signicant energy-dependent morphology is seen. A multi-zone, cylindrically symmetric model is created to investigate tailed-out PWN morphology, accounting for multiple mechanisms for particle transport and cooling. The model is applied to the CTA 1 data, with a limited search of the parameter space performed to t the observed spectrum and extent. Possible improvements to the model performance are discussed.

Author: Markus Holler
Publisher:
ISBN:
Category :
Languages : en
Pages : 60

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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In recent years, Cherenkov telescopes like H.E.S.S. have identified PulsarWind Nebulae (PWNe) at energies between 100 GeV and 100 TeV as one of the main source populations emitting gamma-rays at these energies. PWNe consist of electrons and positrons emitted by pulsars which radiatively cool down by undergoing synchrotron radiation and inverse Compton scattering. In the case of inverse Compton scattering, the resulting photons show energies up to hundreds of TeV and are therefore making PWNe visible in the mentioned energy range. The first part of this work is dedicated to a model describing the spectral and spatial distribution of the gamma-ray emission from PWNe. Its application to the PWN created by the Geminga pulsar shows an agreement with measured flux values obtained by the Milagro and EGRET experiments. The modelled spatial extension coincides with Milagro observations. The aim of the second part is to verify previously derived analytical results concerning the spectral evolution of electrons due to inverse Compton scattering with a Monte-Carlo simulation using the exact Klein-Nishina cross section. Analytically expected spectral shapes have been qualitatively reproduced for both a burst-like and a stationary injection scenario assumingmono-energetic or blackbody distributed target photons.