› › X Ray Observations Of Pulsar Wind Nebulae

Very-high-energy Gamma-ray Observations of Pulsar Wind Nebulae and Cataclysmic Variable Stars with MAGIC and Development of Trigger Systems for IACTs

Author : Rubén López Coto

Publisher : Springer

Page : 241 pages

File Size : 41,95 MB

Release : 2016-09-29

Category : Science

ISBN : 3319447513

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Book Description

This thesis is a comprehensive work that addresses many of the open questions currently being discusssed in the very-high-energy (VHE) gamma-ray community. It presents a detailed description of the MAGIC telescope together with a glimpse of the future Cherenkov Telescope Array (CTA). One section is devoted to the design, development and characterization of trigger systems for current and future imaging atmospheric Cherenkov telescopes. The book also features a state-of-the-art description of pulsar wind nebula (PWN) systems, the study of the multi-TeV spectrum of the Crab nebula, as well as the discovery of VHE gamma rays at the multiwavelength PWN 3C 58, which were sought at these wavelengths for more than twenty years. It also includes the contextualization of this discovery amongst the current population of VHE gamma-ray PWNe. Cataclysmic variable stars represent a new source of gamma ray energies, and are also addressed here. In closing, the thesis reports on the systematic search for VHE gamma-ray emissions of AE Aquarii in a multiwavelength context and the search for VHE gamma-ray variability of novae during outbursts at different wavelengths.



X-ray Observations of Pulsar Wind Nebulae

Author : Benson Guest

Publisher :

Page : 0 pages

File Size : 30,56 MB

Release : 2020

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ISBN :

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Pulsar wind nebulae (PWNe) are non-thermal bubbles blown by the relativistic winds of rapidly rotating neutron stars. They are formed in the cavity evacuated by the explosion of a core collapse supernova, and depending on their evolutionary stage may appear as a region of hard X-ray emission within a shell of million degree gas, or be the only visible remains of the cataclysmic event. With deep observations and spatially resolved X-ray spectroscopy, we probe the environment surrounding PWNe of different ages to search for the missing emission predicted from shock heated gas. We examine the properties of the relativistic winds and compare our results with diffusion models and hydrodynamic simulations. In the process of creating consistent spectral maps of PWNe we discover variability in archival Chandra data, opening a new window for observations and theory to explore. We present the deepest Chandra study of G21.5-0.9, finding faint thermal emission embedded in the primarily non-thermal limb-brightened shell. In analysing the synchrotron emission from the PWN, we find an adequate fit with a spatially averaged diffusion model to describe the transport of the wind through the nebula. Unlike the limb-brightened shell previously revealed in G21.5-0.9 with sufficient observation time, the missing shell in CTB 87 remains hidden despite a deep XMM-Newton observation. We constrain the ambient density and favour expansion into a low density bubble. We attribute the morphology to an interaction of the wind with a reverse shock due to the motion of the pulsar within a ~20 kyr old remnant. We present the first X-ray spectral map of this remnant, and find a good agreement with a simulated map. While merging or simultaneously fitting observations separated by extended periods of time will improve statistics, it may also hide unknown variability. We discover significant spectral variability in G21.5-0.9, 3C58, and Kes 75, and marginal evidence of variability in G11.2-0.3 and G54.1+0.3 to be confirmed with future observations.



X-ray Observations of the Young Pulsar Wind Nebula G21.5-0.9 and the Evolved Pulsar Wind Nebulae CTB 87 (G74.9+1.2) and G63.7+1.1

Author : Heather Matheson

Publisher :

Page : 0 pages

File Size : 12,57 MB

Release : 2010

Category :

ISBN :

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Book Description

Pulsar wind nebulae (PWNe), nebulae harbouring a rotation-powered neutron star that was born in a supernova, provide opportunities to study highly relativistic pulsar winds and their interaction with the surrounding medium. Particularly interesting are PWNe that do not show any sign of the expected surrounding SNR shell and were thought to be born in subenergetic explosions or with unusual progenitors. The detection of a shell around one such PWN suggested that shells are indeed produced but may be faint due to unseen shocked ejecta, a low density environment, and/or a young age that has not yet allowed the shell to brighten and become visible. Here, by using observational X-ray data from modern telescopes with excellent spatial and energy resolution (Chandra and XMM-Newton), we target PWNe that do not have prominent SNR shells, and are known to be in varied environments, to further explore the characteristics of this growing, but poorly explored, class of PWNe. By combining imaging and spectroscopic results, we study the morphology of the PWNe, search for thermal emission from shock-heated material, investigate the energetics of the nebulae, and search for candidates for the neutron stars powering the nebulae. We find that while the faint shell surrounding G21.5-0.9 can be explained as a young PWN evolving in a low density medium, CTB 87 (G74.9+1.2) appears to be in an advanced stage of evolution, and G63.7+1.1 appears to be both in an advanced stage of evolution and in a dense environment. By performing spatially resolved spectroscopy, we have shown how the spectral characteristics vary across the PWNe, and note that more data will place better constraints on possible thermal emission in these remnants. The imaging portion of these studies has revealed intriguing large-scale morphologies for CTB 87 and G63.7+1.1, as well as a torus-jet structure in CTB 87 and neutron star candidates in both CTB 87 and G63.7+1.1. We conclude that both CTB 87 and G63.7+1.1 are likely interacting with the supernova remnant reverse shock, and CTB 87 may be additionally influenced by the motion of its neutron star.



Revealing the Most Energetic Light from Pulsars and Their Nebulae

Author : David Carreto Fidalgo

Publisher : Springer

Page : 213 pages

File Size : 12,19 MB

Release : 2019-07-17

Category : Science

ISBN : 3030241947

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Book Description

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.



Handbook of Supernovae

Author : Athem W. Alsabti

Publisher :

Page : pages

File Size : 22,40 MB

Release :

Category : Supernovae

ISBN : 9783319207940

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The Search For Pulsar Wind Nebulae in the Very High Energy Gamma-ray Regime

Author : Dominic Robert Keogh

Publisher :

Page : pages

File Size : 36,20 MB

Release : 2010

Category : Gamma ray astronomy

ISBN :

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Book Description

The aim of this Thesis is to study the development of pulsar wind nebulae in the TeV regime and in doing so uncover more sources which have as yet not been observed at these wavelengths. It is found that the extent of pulsar wind nebula in the TeV gamma-ray increases with its age while no developmental relationship is seen concerning the luminosity or spectral index of the nebulae when observed in the TeV gamma-ray regime due to uncertainties in the measurements available. TeV gamma-ray upper limits are calculated for several nebulae observed in the X-ray regime allowing the strength of their magnetic fields to be constrained but only one new source, which was previously confused with its companion, was discovered, the Eel Nebula. Predictions of the fluxes of many of the sources for which upper limits are derived in this work have been calculated from observations of their emission in X-rays and some of these sources should be uncovered with the next generation CTA instrument.



Modelling Pulsar Wind Nebulae

Author : Diego F. Torres

Publisher : Springer

Page : 318 pages

File Size : 36,94 MB

Release : 2017-11-13

Category : Science

ISBN : 3319630318

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Book Description

In view of the current and forthcoming observational data on pulsar wind nebulae, this book offers an assessment of the theoretical state of the art of modelling them. The expert authors also review the observational status of the field and provide an outlook for future developments. During the last few years, significant progress on the study of pulsar wind nebulae (PWNe) has been attained both from a theoretical and an observational perspective, perhaps focusing on the closest, more energetic, and best studied nebula: the Crab, which appears in the cover. Now, the number of TeV detected PWNe is similar to the number of characterized nebulae observed at other frequencies over decades of observations. And in just a few years, the Cherenkov Telescope Array will increase this number to several hundreds, actually providing an essentially complete account of TeV emitting PWNe in the Galaxy. At the other end of the multi-frequency spectrum, the SKA and its pathfinder instruments, will reveal thousands of new pulsars, and map in exquisite detail the radiation surrounding them for several hundreds of nebulae. By carefully reviewing the state of the art in pulsar nebula research this book prepares scientists and PhD students for future work and progress in the field.





Particle Populations and High Energy Emission in Pulsar Wind Nebulae

Author : Albert Adam Van Etten

Publisher :

Page : pages

File Size : 22,83 MB

Release : 2012

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ISBN :

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Book Description

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.