Lobservation Des Pulsars Au Radiotelescope De Nancay

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L'observation des pulsars au Radiotélescope de Nançay

Author : Grégory Desvignes
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (69 download)

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Book Synopsis L'observation des pulsars au Radiotélescope de Nançay by : Grégory Desvignes

Download or read book L'observation des pulsars au Radiotélescope de Nançay written by Grégory Desvignes and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Un pulsar est une étoile à neutrons en rotation rapide et dotée d'un fort champ magnétique qui peut se manifester en émettant sur tout le spectre électromagnétique. Dans cette thèse, je m'intéresse au rayonnement radio produit par l'étoile. Je commence ainsi par décrire l'instrumentation de dédispersion cohérente à base de GPUs installée au Radiotélescope de Nançay avec deux autres modes d'observation que j'ai développés : un mode pour la recherche de nouveaux pulsar et un mode spectromètre. Une autre partie de ce travail détaille le retraitement en cours du sondage Foster fait à la fin des années 90 à Nançay ainsi que de nouvelles observations ciblées, sur des candidats HESS notamment. Je présente ensuite les résultats obtenus sur les pulsars relativistes J0737-3039A et J1906+0746 avec respectivement des tests de la Relativité Générale et la mesure de la précession géodétique. Des données de polarimétrie ont ainsi permis de déterminer la géométrie du système de PSR J1906+0746. Enfin, je termine par l'analyse des temps d'arrivées de 20 pulsars millisecondes observés à Nançay dans le cadre de l'EPTA, une collaboration européenne pour un réseau de chronométrage pulsar avec pour objectif la détection d'un fond d'ondes gravitationnelles, possible d'ici 5 à 10 ans.

Première caractérisation de la population de pulsars radio à basses fréquences avec NenuFAR

Author : Louis Bondonneau
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (123 download)

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Book Synopsis Première caractérisation de la population de pulsars radio à basses fréquences avec NenuFAR by : Louis Bondonneau

Download or read book Première caractérisation de la population de pulsars radio à basses fréquences avec NenuFAR written by Louis Bondonneau and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Un pulsar est une étoile à neutrons en rotation rapide (typiquement un tour par seconde) dont le faisceau d'émission radio provenant des pôles magnétiques de l'étoile balaie l'univers. Quand le faisceau intercepte la Terre, le pulsar est détectable comme une série de pulsations régulières dans dans un vaste domaine de longueurs d'onde, de la radio jusqu'aux rayons gamma. Au cours de cette thèse j'ai utilisé, adapté et développé des méthodes d'analyses ainsi qu'un pipeline de traitement de signal en temps réel afin d'étudier les signaux radio des pulsars dans la gamme des basses fréquences utilisée par les radiotélescopes LOFAR(LOw Frequency Array) et NenuFAR (New Extension in Nançay Upgrading loFAR).NenuFAR est le nouvel instrument de la station de Radioastronomie de Nançay, construit pour observer le ciel entre 10 et 85 MHz de fréquence. C'est un réseau compact de nouvelle génération, constitué à terme de 1938 antennes phasées analogiquement et numériquement. Depuis le début de ma thèse, j'ai participé activement au développement, puis à la recette de ce nouvel instrument, jusqu'à son ouverture à la communauté scientifique le 1er juillet 2019 dans le cadre d'un appel à "Early Science".Le premier chapitre de ma thèse est consacré à la description du phénomène « pulsar », de l'émission du rayonnement dans la magnétosphère de l'étoile à neutrons jusqu'à l'observation du signal par le radiotélescope. Le second chapitre décrit l'instrumentation des radiotélescopes utilisés pendant la thèse, et en particulier, la conception du dédisperseur « pulsar » cohérent en temps réel de NenuFAR (LUPPI) et du « pipeline » de traitement des observations. Le troisième chapitre est réservé à l'étude d'une centaine de pulsars observés à basse fréquence avec LOFAR. Les données sont issues de deux relevés, l'un effectué avec le coeur de LOFAR (situé aux Pays-Bas) et l'autre avec la station LOFAR de Nançay. Finalement, le dernier chapitre est dédié à la mise en service de NenuFAR et aux premiers résultats scientifiques obtenus pour les observations des pulsars. Ce chapitre décrit en particulier les tests pour les différents modes d'observation (dédispersion cohérente, multi-beam, single pulse, enregistrement en forme d'onde) et le résultat du premier grand relevé du ciel Nord par NenuFAR, qui a permis à partir de l'observation de 500 pulsars la détection de 130 sources, dont plus de 50 pour la première fois à ces fréquences. J'y présente également le programme scientifique du projet clé pulsars de NenuFAR, que j'ai fortement contribué à mettre en place.

Pulsar Astronomy

Author : Andrew Lyne
Publisher : Cambridge University Press
ISBN 13 : 1108864104
Total Pages : 422 pages
Book Rating : 4.1/5 (88 download)

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Book Synopsis Pulsar Astronomy by : Andrew Lyne

Download or read book Pulsar Astronomy written by Andrew Lyne and published by Cambridge University Press. This book was released on 2022-08-04 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: After more than half a century since their unexpected discovery and identification as neutron stars, the observation and understanding of pulsars touches upon many areas of astronomy and astrophysics. The literature on pulsars is vast and the observational techniques used now cover the whole of the electromagnetic spectrum from radio to gamma-rays. Now in its fifth edition, this volume has been reorganised and features new material throughout. It provides an introduction in historical and physical terms to the many aspects of neutron stars, including condensed matter, physics of the magnetosphere, supernovae and the development of the pulsar population, propagation in the interstellar medium, binary stars, gravitation and general relativity. The current development of a new generation of powerful radio telescopes, designed with pulsar research in mind, makes this survey and guide essential reading for a growing body of students and astronomers.

High-Sensitivity Radio Astronomy

Author : N. Jackson
Publisher : Cambridge University Press
ISBN 13 : 9780521573504
Total Pages : 332 pages
Book Rating : 4.5/5 (735 download)

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Book Synopsis High-Sensitivity Radio Astronomy by : N. Jackson

Download or read book High-Sensitivity Radio Astronomy written by N. Jackson and published by Cambridge University Press. This book was released on 1997-01-28 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced sensitivity radio telescopes are producing dramatic results. An international conference was held in Jodrell Bank to take stock of these advances. This timely volume presents the review articles presented by a host of world experts who gathered at this meeting. We are shown how high sensitivity is advancing our understanding in radio spectral line analysis, radio continuum observations of galaxies, cosmology, pulsars, and radio emission from stars; what new and enhanced instruments are now available and those planned for the future. This volume provides graduate students and researchers with an up-to-date and wide-ranging review of the new and future research possible with high-sensitivity radio telescopes.

Gravitational Wave Detection and Data Analysis for Pulsar Timing Arrays

Author : Rutger van Haasteren
Publisher : Springer Science & Business Media
ISBN 13 : 3642395996
Total Pages : 149 pages
Book Rating : 4.6/5 (423 download)

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Book Synopsis Gravitational Wave Detection and Data Analysis for Pulsar Timing Arrays by : Rutger van Haasteren

Download or read book Gravitational Wave Detection and Data Analysis for Pulsar Timing Arrays written by Rutger van Haasteren and published by Springer Science & Business Media. This book was released on 2013-09-12 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsar timing is a promising method for detecting gravitational waves in the nano-Hertz band. In his prize winning Ph.D. thesis Rutger van Haasteren deals with how one takes thousands of seemingly random timing residuals which are measured by pulsar observers, and extracts information about the presence and character of the gravitational waves in the nano-Hertz band that are washing over our Galaxy. The author presents a sophisticated mathematical algorithm that deals with this issue. His algorithm is probably the most well-developed of those that are currently in use in the Pulsar Timing Array community. In chapter 3, the gravitational-wave memory effect is described. This is one of the first descriptions of this interesting effect in relation with pulsar timing, which may become observable in future Pulsar Timing Array projects. The last part of the work is dedicated to an effort to combine the European pulsar timing data sets in order to search for gravitational waves. This study has placed the most stringent limit to date on the intensity of gravitational waves that are produced by pairs of supermassive black holes dancing around each other in distant galaxies, as well as those that may be produced by vibrating cosmic strings. Rutger van Haasteren has won the 2011 GWIC Thesis Prize of the Gravitational Wave International Community for his innovative work in various directions of the search for gravitational waves by pulsar timing. The work is presented in this Ph.D. thesis.

Nuclear Science Abstracts

Author :
Publisher :
ISBN 13 :
Total Pages : 958 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis Nuclear Science Abstracts by :

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975-08 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Galactic Radio Astronomy

Author : F.J. Kerr
Publisher : Springer Science & Business Media
ISBN 13 : 9401022631
Total Pages : 629 pages
Book Rating : 4.4/5 (1 download)

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Book Synopsis Galactic Radio Astronomy by : F.J. Kerr

Download or read book Galactic Radio Astronomy written by F.J. Kerr and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 629 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Galactic Radio Astronomy' was chosen as the subject of this Symposium, which was held in conjunction with the IAU General Assembly that took place in Sydney in August 1973, largely because it is a very suitable Southern Hemisphere topic. This results in part from the advantages of a southern location in studying the Galaxy and in part from the long association of Australia with radio astronomy. Following the General Assembly, the Symposium was held at the Surf air Inter national Hotel in Maroochydore, Queensland, from 3 to 7 September, 1973. The conference participants were effectively isolated from the rest of the world during the Symposium, and the excellent spring weather and geographical situation led to the development of an unusually good rapport. The Symposium was sponsored by Commissions 40, 33, and 34. The Organizing Committee was composed of A. H. Barrett (chairman), J. E. Baldwin, D. S. Heeschen, F. J. Kerr, J. Lequeux, S. W. McCuskey, P. G. Mezger, B. Y. Mills, Yu. N. Parijskij, B. J. Robinson, H. van der Laan, and H. F. Weaver. The Local Committee, consisting ofB. J. Robinson, N. G. Seddon, and P. J. Kelly, looked after the arrangements in very fine style. The Symposium was supported financially by the IAU, the Australian Academy o~ Science, the CSIRO Division of Radiophysics, Union Carbide Australia Limited, and the Science Foundation for Physics within the University of Sydney.

Understanding Pulsars and Space Navigations

Author : Ping Shuai
Publisher : Springer Nature
ISBN 13 : 9811610673
Total Pages : 437 pages
Book Rating : 4.8/5 (116 download)

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Book Synopsis Understanding Pulsars and Space Navigations by : Ping Shuai

Download or read book Understanding Pulsars and Space Navigations written by Ping Shuai and published by Springer Nature. This book was released on 2021-04-16 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically presents the concept, history, implementation, theory system and basic methods of pulsar and space flight, illustrating the characteristics of pulsars. It also describes the classification of spacecraft navigation systems and the autonomous navigation technologies, as well as X-ray pulsar-based navigation systems (XPNAV) and discusses future navigation satellite systems in detail.

Simulation de la scintillation interstellaire des pulsars

Author : Mourad Hamidouche
Publisher :
ISBN 13 :
Total Pages : 188 pages
Book Rating : 4.:/5 (495 download)

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Book Synopsis Simulation de la scintillation interstellaire des pulsars by : Mourad Hamidouche

Download or read book Simulation de la scintillation interstellaire des pulsars written by Mourad Hamidouche and published by . This book was released on 2003 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nous tentons dans cette thèse d'interpréter les Extreme Scattering Events (ESE's) par la turbulence naturelle du milieu interstellaire (MIS) ionisé. Il est bien connu que les inhomogénéités du MIS ionisé suivent un spectre de puissance de Kolmogorov. Dans l'approximation de l'écran mince, on montre d'abord en optique géométrique qu'on peut produire le phénomène d'ESE. On effectue ensuite le calcul dans le cadre de la diffraction de Fresnel. On obtient des pseudo-ESEs qui ne sont pas très profonds et n'apparaissent pas au même moment aux trois fréquences simulées comme dans le cas des observations du pulsar B1937+21 au radiotélescope de Nançay. On montre par contre que les paramètres obtenus de la scintillation simulée sont en très bon accord avec les observations et la théorie. Cette étude conduite sur un ALPHA server est une première étape nécessaire et importante dans l'étude de la scintillation interstellaire.

27th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting

Author :
Publisher :
ISBN 13 :
Total Pages : 512 pages
Book Rating : 4.:/5 (317 download)

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Book Synopsis 27th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting by :

Download or read book 27th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting written by and published by . This book was released on 1996 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Pulsar Timing, General Relativity, and the Internal Structure of Neutron Stars

Author : Zaven Arzoumanian
Publisher :
ISBN 13 :
Total Pages : 376 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Pulsar Timing, General Relativity, and the Internal Structure of Neutron Stars by : Zaven Arzoumanian

Download or read book Pulsar Timing, General Relativity, and the Internal Structure of Neutron Stars written by Zaven Arzoumanian and published by . This book was released on 1999 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Clocks in the Sky

Author : Geoff McNamara
Publisher : Springer Science & Business Media
ISBN 13 : 038776562X
Total Pages : 192 pages
Book Rating : 4.3/5 (877 download)

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Book Synopsis Clocks in the Sky by : Geoff McNamara

Download or read book Clocks in the Sky written by Geoff McNamara and published by Springer Science & Business Media. This book was released on 2009-04-24 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsars are rapidly spinning neutron stars, the collapsed cores of once massive stars that ended their lives as supernova explosions. In this book, Geoff McNamara explores the history, subsequent discovery and contemporary research into pulsar astronomy. The story of pulsars is brought right up to date with the announcement in 2006 of a new breed of pulsar, Rotating Radio Transients (RRATs), which emit short bursts of radio signals separated by long pauses. These may outnumber conventional radio pulsars by a ratio of four to one. Geoff McNamara ends by pointing out that, despite the enormous success of pulsar research in the second half of the twentieth century, the real discoveries are yet to be made including, perhaps, the detection of the hypothetical pulsar black hole binary system by the proposed Square Kilometre Array - the largest single radio telescope in the world.

Neutron Stars and Pulsars

Author : Werner Becker
Publisher : Springer Science & Business Media
ISBN 13 : 354076965X
Total Pages : 702 pages
Book Rating : 4.5/5 (47 download)

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Book Synopsis Neutron Stars and Pulsars by : Werner Becker

Download or read book Neutron Stars and Pulsars written by Werner Becker and published by Springer Science & Business Media. This book was released on 2009-02-11 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only reviews the progress made since the early days of pulsar astronomy, but especially focuses on questions such as: "What have we learned about the subject and how did we learn it?", "What are the most important open questions in this area?" and "What new tools, telescopes, observations, and calculations are needed to answer these questions?". All authors who have contributed to this book have devoted a significant part of their scientific careers to exploring the nature of neutron stars and understanding pulsars. Everyone has paid special attention to writing educational comprehensive review articles with the needs of beginners, students and young scientists as potential readers in mind. This book will be a valuable source of information for these groups.

Isolated Pulsars

Author : K. A. van Riper
Publisher : Cambridge University Press
ISBN 13 : 9780521434294
Total Pages : 456 pages
Book Rating : 4.4/5 (342 download)

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Book Synopsis Isolated Pulsars by : K. A. van Riper

Download or read book Isolated Pulsars written by K. A. van Riper and published by Cambridge University Press. This book was released on 1993-03-25 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: The extreme properties of pulsars demand a broad range of physics. From The Los Alamos Workshop on Isolated Pulsars contributions have been selected to encompass all aspects of pulsar detection and understanding. Recent observational highlights include results from the Compton Gamma-Ray Observatory, ROSAT and GINGA and the Hubble Space Telescope. Well-illustrated theoretical contributions cover a wide range of topics. This volume forms a comprehensive and up-to-date guide to the observation and theory of solitary neutron stars.

Détection d'évènements impulsionnels en environnement radioélectrique perturbé

Author : Dalal Ait Allal
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (867 download)

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Book Synopsis Détection d'évènements impulsionnels en environnement radioélectrique perturbé by : Dalal Ait Allal

Download or read book Détection d'évènements impulsionnels en environnement radioélectrique perturbé written by Dalal Ait Allal and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les travaux présentés dans ce mémoire s'inscrivent dans le cadre de la détection d'évènements impulsionnels intermittents en provenance de pulsars. Ces objets astrophysiques sont des étoiles à neutrons hautement magnétisées en rotation rapide, qui émettent un faisceau radio balayant l'espace comme la lentille d'un phare. Ils sont détectables grâce à une instrumentation spécifique. Depuis quelques années, on a découvert de nouvelles catégories de ces pulsars, aux caractéristiques extrêmes, avec en particulier des impulsions individuelles plus intenses et irrégulières comparé à la moyenne. Il faut pouvoir les détecter en temps réel dans un environnement radio perturbé à cause des signaux de télécommunications. Cette étude propose des algorithmes de traitement d'interférences radio fréquence (RFI) adaptés à ce contexte. Plusieurs méthodes de traitement de RFI sont présentées et comparées. Parmi elles, deux ont été retenues et comparées au moyen de simulations Monte Carlo, avec un jeu de paramètres simulant le pulsar et un signal BPSK avec des puissances et des durées différentes. Pour la recherche de nouveaux pulsars, une méthode alternative est proposée (SIPSFAR), combinant capacité de recherche en temps réel et robustesse contre les RFI. Elle est basée sur la transformée de Fourier 2D et la transformée de Radon. Une étude comparative théorique a permis de confronter et comparer la sensibilité de cette nouvelle méthode avec celle communément utilisée par les radioastronomes. La méthode a été implantée sur un GPU GTX285 et testée sur un grand relevé du ciel effectué au radiotélescope de Nançay. Les résultats obtenus ont donné lieu à une comparaison statistique complémentaire à partir de données réelles.

Pulsar Timing, General Relativity, and the Internal Structure of Neutron Stars

Author :
Publisher :
ISBN 13 :
Total Pages : 378 pages
Book Rating : 4.5/5 (164 download)

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Book Synopsis Pulsar Timing, General Relativity, and the Internal Structure of Neutron Stars by :

Download or read book Pulsar Timing, General Relativity, and the Internal Structure of Neutron Stars written by and published by . This book was released on 1951 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Relativity in Fundamental Astronomy (IAU S261)

Author : International Astronomical Union. Symposium
Publisher : Cambridge University Press
ISBN 13 : 9780521764810
Total Pages : 464 pages
Book Rating : 4.7/5 (648 download)

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Book Synopsis Relativity in Fundamental Astronomy (IAU S261) by : International Astronomical Union. Symposium

Download or read book Relativity in Fundamental Astronomy (IAU S261) written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2010-01-28 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU S261 summarizes the present state of applied relativity, and discusses the applications and future tests of general relativity.