Dissertations / Theses on the topic 'High Energy Astrophysics; Cosmic Rays'
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Lee, Anthony A. "Application of Monte Carlo methods to some problems in high energy astrophysics /." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phl4768.pdf.
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Chadwick, Mary Paula. "Very high energy cosmic gamma rays from radio and X-ray pulsars." Thesis, Durham University, 1987. http://etheses.dur.ac.uk/6720/.
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This thesis is concerned with the detection of very high energy cosmic gamma-rays from isolated pulsars and X-ray binary sources using the atmospheric Cerenkov technique. A general introduction to gamma ray detection techniques is followed by adscription of the properties of atmospheric Cerenkov radiation and a discussion of the principles of the atmospheric Cerenkov technique. The Mark I and Mark II gamma-ray telescopes operated in Dugway, Utah by the University of Durham between 1981 and 1984 are briefly described. There follows a discussion of the results from observations at many different wavelengths of Cygnus X-3. This object was observed by the Durham group between 1981 and 1983 in Dugway Utah and also in Durham during autumn 1985. The detection in the Dugway data of the 4.8 hr X-ray period and the possible detection of a19.2 day intensity variation are considered. The discovery of a 12.59 ms pulsar in data taken on Cygnus X-3 in 1983 is described. Evidence is presented which suggests this periodicity is also present at a weaker level in earlier data and also in the data taken in Durham in 1985.Results from observations of PSR1937+21 , PSR1953+29and six radio pulsars , are presented. The design and construction of the Mark III telescope, now operating in Narrabri , N.S.W. , is described in detail. Preliminary results from observations with the Mark III telescope of three objects, LMC X-4, the Vela pulsar and CentaurusX-3, are presented, with particular reference to periodicities inherent in the sources. An observation of the supernova in the Large Magellanic Cloud is discussed. A brief discussion of the mechanisms by which V.H.E. gamma-rays may be produced in isolated pulsars and X-ray binary pulsars is given, followed by a description of the future prospects for the Mark III and Mark IV telescopes.
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Taylor, Andrew Martin. "The propagation of ultra high energy cosmic rays." Thesis, University of Oxford, 2007. http://ora.ox.ac.uk/objects/uuid:63572ebe-fb32-41b6-8b91-a7294db135a6.
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This thesis presents theoretical work on the propagation of ultra high energy cosmic rays, from their source to Earth. The different energy loss processes, resulting from cosmic ray interactions with the radiation fields, are addressed. The subsequent uncertainties in the energy loss rates and the effect produced on the arriving cosmic ray spectrum are highlighted. The question of the composition of ultra high energy cosmic rays remains unresolved, with the range of possibilities leading to quite different results in both the secondary fluxes of particles produced through cosmic ray energy loss interactions en route, and the arriving cosmic ray spectra at Earth. A large range of nuclear species are considered in this work, spanning the range of physically motivated nuclear types ejected from the cosmic ray source. The treatment of cosmic ray propagation is usually handled through Monte Carlo simulations due to the stochastic nature of some of the particle physics processes relevant. In this work, an analytic treatment for cosmic ray nuclei propagation is developed. The development of this method providing a deeper understanding of the main components relevant to cosmic ray nuclei propagation, and through its application, a clear insight into the contributing particle physics aspects of the Monte Carlo simulation. A flux of secondary neutrinos, produced as a consequence of cosmic ray energy loss through pion production during propagation, is also expected to be observed at Earth. This spectrum, however, is dependent on several loosely constrained factors such as the radiation field in the infrared region and cosmic ray composition. The range of possible neutrino fluxes obtainable with such uncertainties are discussed in this work. High energy cosmic ray interactions with the radiation fields present within the source may also occur, leading to cosmic ray energy loss before the cosmic ray has even managed to escape. The secondary spectra produced are investigated through the consideration of three candidate sources. A relationship between the degree of photo-disintegration in the source region and the neutrino flux produced through p γ interactions is found.
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Brandt, Theresa J. "On High Energy Cosmic Rays from the CREAM Instrument." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259540765.
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Szabo, Anthony Paul. "High energy emissions for astrophysical objects." Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phs996.pdf.
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Gabici, Stefano. "Gamma ray astronomy and the origin of galactic cosmic rays." Habilitation à diriger des recherches, Université Paris-Diderot - Paris VII, 2011. http://tel.archives-ouvertes.fr/tel-00719791.
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Diffusive shock acceleration operating at expanding supernova remnant shells is by far the most popular model for the origin of galactic cosmic rays. Despite the general consensus received by the model, an unambiguous and conclusive proof of the supernova remnant hypothesis is still missing. In this context, the recent developments in gamma ray astronomy provide us with precious insights into the problem of the origin of galactic cosmic rays, since production of gamma rays is expected both during the acceleration of cosmic rays at supernova remnant shocks and during their subsequent propagation in the interstellar medium. In particular, the recent detection of a number of supernova remnants at TeV energies nicely fits with the model, but it still does not constitute a conclusive proof of it, mainly due to the difficulty of disentangling the hadronic and leptonic contributions to the observed gamma ray emission. The main goal of my research is to search for an unambiguous and conclusive observational test for proving (or disproving) the idea that supernova remnants are the sources of galactic cosmic rays with energies up to (at least) the cosmic ray knee. Our present comprehension of the mechanisms of particle acceleration at shocks and of the propagation of cosmic rays in turbulent magnetic fields encourages beliefs that such a conclusive test might come from future observations of supernova remnants and of the Galaxy in the almost unexplored domain of multi-TeV gamma rays.
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MacRae, John Hamish Kenneth. "The detection of very high energy cosmic gamma rays using the atmospheric Cerenkov technique." Thesis, Durham University, 1985. http://etheses.dur.ac.uk/7854/.
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This thesis is concerned with the detection of very high energy cosmic gamma rays using the atmospheric Cerenkov technique. A general introduction to gamma ray detection techniques is followed by a detailed discussion of the principles of the atmospheric Cerenkov technique and the history of its use prior to this work. The design and operation of the University of Durham facility in Dugway, Utah is described in depth. Monte Carlo computer simulations have been developed to assist in both the understanding of the equipment and the analysis of the results for the Durham facility. The variation of the response of the array with zenith angle and detector threshold has been investigated and the aperture function of a single telescope calculated. The latter has been found to be a complicated function of both zenith angle and detector threshold. Computer simulations have also been developed to aid in the design of a camera to record two-dimensional Cerenkov light images from small extensive air showers, and to provide a means of testing analysis routines; these are discussed. The camera is located at the F.L. Whipple Observatory in Arizona. The techniques employed in the analysis of data recorded by the Dugway facility are discussed, and a computer package developed to aid in the routine aspects of the analysis is described. Results of observations from two sources, Cygnus X-3 and PSR0531, are presented, with particular reference to periodicities inherent in the sources and to bursts of gamma ray emission. The discussion of the results includes a review of the various models which have been proposed for Cygnus X-3.
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Morris, Chad Michael. "Detection Techniques of Radio Emission from Ultra High Energy Cosmic Rays." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1254506832.
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Pinzke, Anders. "Gamma-Ray Emission from Galaxy Clusters : DARK MATTER AND COSMIC-RAYS." Doctoral thesis, Stockholms universitet, Fysikum, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-42453.
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The quest for the first detection of a galaxy cluster in the high energy gamma-ray regime is ongoing, and even though clusters are observed in several other wave-bands, there is still no firm detection in gamma-rays. To complement the observational efforts we estimate the gamma-ray contributions from both annihilating dark matter and cosmic-ray (CR) proton as well as CR electron induced emission. Using high-resolution simulations of galaxy clusters, we find a universal concave shaped CR proton spectrum independent of the simulated galaxy cluster. Specifically, the gamma-ray spectra from decaying neutral pions, which are produced by CR protons, dominate the cluster emission. Furthermore, based on our derived flux and luminosity functions, we identify the galaxy clusters with the brightest galaxy clusters in gamma-rays. While this emission is challenging to detect using the Fermi satellite, major observations with Cherenkov telescopes in the near future may put important constraints on the CR physics in clusters. To extend these predictions, we use a dark matter model that fits the recent electron and positron data from Fermi, PAMELA, and H.E.S.S. with remarkable precision, and make predictions about the expected gamma-ray flux from nearby clusters. In order to remain consistent with the EGRET upper limit on the gamma-ray emission from Virgo, we constrain the minimum mass of substructures for cold dark matter halos. In addition, we find comparable levels of gamma-ray emission from CR interactions and dark matter annihilations without Sommerfeld enhancement.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted.
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Burton, Ross E. "Upper Limits on the Ultra-High Energy Cosmic Ray Flux from Unresolved Sources." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1323452264.
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LaHurd, Danielle V. "Searching for Quark Gluon Plasma Signatures in Ultra High Energy Cosmic Rays." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1479298851843212.
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Murase, Kota. "High-Energy Phenomena in Extreme Astrophysical Objects and the Origin of High-Energy Cosmic Rays." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120655.
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Graham, Lilian Joan. "Ultra high energy gamma ray point sources and cosmic ray anisotropy." Thesis, Durham University, 1994. http://etheses.dur.ac.uk/5594/.
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The experimental set-up at the Baksan Air Shower Array, used to detect air showers above ~0.2xl0(^14)eV, is described. An estimation of the angular resolution using the cosmic ray shadow of the Sun and the Moon gives a value of ~2.5˚ which is consistent with previous estimates from Monte-Carlo simulations. Using data from this array covering 1985-1992, a search is made for 7-ray emission from 18 candidate sources. Upper limits to the flux from these sources are stated in all cases. A periodicity search is made on data for which the excess for a single transit of a particular source is above 3(7. The results of this periodicity analysis on such days points to 4 possible observations of pulsed emission at the 95% confidence level. These are 4U0115+63 on 19.03.89, PSR19534-29 on 12.02.85, 1E2259+586 on 01.08.91 and PSR0655+64 on 12.08.89. Without confirmation from other groups however the findings are not significant enough to stand alone. A harmonic analysis has been performed on the 8 years of data and after pressure corrections and a Farley & Storey analysis to eradicate any spurious sidereal variations we find negligible evidence of 2nd or 3rd harmonic but a 1st harmonic amplitude and phase of (12.7 ±1.2) x 10(^-4) at 23.1 ± 0.3hr right ascension. When one takes into account the cosϐ effect on the sidereal anisotropy this value becomes 17.4±1.6xl0(^-4).Future developments and improvements to be undertaken at BASA, including the building of a muon detector, are outlined.
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Griffith, Nathan E. "Microwave Detection of Cosmic Rays and Multi-Messenger Analysis of the Parameters of Ultra-High Energy Astrophysical Sources." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429799044.
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Stapleton, James C. "Ultra-High Energy Cosmic Rays: Composition, Early Air Shower Interactions, and Xmax Skewness." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431044195.
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Voigt, Bernhard. "Sensitivity of the IceCube detector for ultra-high energy electron-neutrino events." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15850.
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Zur Zeit wird das IceCube Neutrino-Teleskop am Südpol im Eis der Antarktis installiert, die Hälfte des Detektors ist bereits im Betrieb. Bei Fertigstellung im Jahr 2011 wird mehr als 1 km^3 Eis mit Photovervielfachern instrumentiert sein. IceCube bietet damit eine einzigartige Möglichkeit, die Quellen der kosmischen Strahlung mit Hilfe hochenergetischer Neutrinos zu finden. Im Rahmen dieser Arbeit wurde die Sensitivität des kompletten Icecube Detektors für den Nachweis eines diffusen Flusses von Elektronneutrinos bestimmt. Ziel war es, die Eigenschaften des Detektors für Energien oberhalb von einem PeV zu bestimmen. Besonderes Augenmerk wurde dabei auf die Simulation von elektromagnetischen Kaskaden gelegt, die in Neutrino-Nukleon-Wechselwirkungen auftreten. Da existierende Parametrisierungen die Unterdrückung der Wechselwirkungsquerschnitte durch den LPM-Effekt nicht beinhalten, wurde eine Simulation des Energieverlustes von elektromagnetischen Kaskaden für Energien oberhalb von 1 PeV entwickelt, die entsprechend modifizierte Wirkungsquerschnitte verwendet. Die Analyse, die in dieser Arbeit vorgestellt wird, nutzt die komplette Information des durch einen Photovervielfacher aufgezeichneten Ladungsverlaufes aus, die mit der Datennahme des IceCube Detektors zur Verfügung steht. Es werden neue Methoden entwickelt, um zwischen atmosphärischen Myonen-Hintergrund- und Signalereignissen von Kaskaden aus Neutrino-Nukleon-Wechselwirkungen zu unterscheiden. Die erreichbare Sensitivität innerhalb einer Laufzeit von einem Jahr ist 1.5*10^-8 E^-2 GeV/(cm^2 sr s) in einem Energiebereich von 16 TeV bis 13 PeV für den Nachweis von Elektronneutrinos eines diffusen Flusses. Eine Verbesserung von mindestens einer Größenordnung wird erwartet, wenn alle Neutrinofamilien in die Analyse einbezogen werden. Damit sollte eine Sensitivität erreicht werden, die auf dem gleichen Niveau einer diffusen Myonenanalyse liegt.IceCube is a neutrino telescope currently under construction in the glacial ice at South Pole. At the moment half of the detector is installed, when completed it will instrument 1 km^3 of ice providing a unique experimental setup to detect high energy neutrinos from astrophysical sources. In this work the sensitivity of the complete IceCube detector for a diffuse electron-neutrino flux is analyzed, with a focus on energies above 1 PeV. Emphasis is put on the correct simulation of the energy deposit of electromagnetic cascades from charged-current electron-neutrino interactions. Since existing parameterizations lack the description of suppression effects at high energies, a simulation of the energy deposit of electromagnetic cascades with energies above 1 PeV is developed, including cross sections which account for the LPM suppression of bremsstrahlung and pair creation. An attempt is made to reconstruct the direction of these elongated showers. The analysis presented here makes use of the full charge waveform recorded with the data acquisition system of the IceCube detector. It introduces new methods to discriminate efficiently between the background of atmospheric muons, including muon bundles, and cascade signal events from electron-neutrino interactions. Within one year of operation of the complete detector a sensitivity of 1.5*10^-8 E^-2 GeV/(cm^2 sr s) is reached, which is valid for a diffuse electron-neutrino flux in the energy range from 16 TeV to 13 PeV. Including all neutrino flavors in this analysis, an improvement of at least one order of magnitude is expected, reaching the anticipated performance of a diffuse muon analysis.
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Sutherland, Michael. "A Method for Establishing Constraints on Galactic Magnetic Field Models Using Ultra High Energy Cosmic Rays and Results from the Data of the Pierre Auger Observatory." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274798328.
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Quinn, Sean P. "Arrival Direction Probabilities of Ultra High Energy Cosmic Rays with the Pierre Auger Observatory and Progress Toward an in-situ Cross-calibration of Auger and Telescope Array Surface Detector Stations." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1512730856642865.
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Halliday, Robert Paul. "Electronics and Timing for the AugerPrime Upgrade and Correlation of Starburst Galaxies with Arrival Directions of Ultra High Energy Cosmic Rays." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1553599216169462.
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Grégoire, Timothée. "Search for high energy neutrinos from the Galactic plane with the ANTARES neutrino telescope." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC129/document.
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Deux analyses sont présentées dans cette thèse. Une première analyse exploite les données du télescope à neutrino ANTARES pour sonder la présence d'un flux de neutrino diffus galactique. Cette analyse se base sur un modèle récent de propagation des rayons cosmiques dans la galaxie, le modèle KRAγ. Ce modèle prédit un flux de neutrinos particulièrement élevé et proche de la sensibilité des télescopes à neutrinos actuels. Il existe deux versions de ce modèle correspondant à différentes coupures sur l'énergie des rayons cosmiques, à 5 et 50 PeV/nucléon. Une méthode de maximisation d'une fonction de vraisemblance est utilisée pour prendre en compte les caractéristiques du modèle, autant spatiales qu'en énergie. Cette analyse a également été combinée avec les données de l'expérience IceCube dans le but d'exploiter au mieux les données actuelles. Des limites ont été mises sur ce modèle rejetant la version avec une coupure à 50 PeV et limitant la version avec une coupure à 5 PeV à moins de 1,2 fois le flux prédit par le modèle. Une deuxième analyse de suivi du signal d'ondes gravitationnelles GW170817 par le télescope à neutrino ANTARES est également présentée. Le signal d'onde gravitationnelles GW170817 résulte de la coalescence d'une binaire d'étoiles à neutrons. Cette deuxième analyse a pour objectif de sonder la présence d'un flux de neutrinos provenant de cet événement en cherchant des neutrinos corrélés spatialement et temporellement. J'ai pris part à cette analyse en y ajoutant les événement de type cascade. Aucun événement n'a été détecté en corrélation, des limites ont été mises sur le flux de neutrino attenduTwo analyses are detailed in this thesis. A first analysis exploit the data of the ANTARES neutrino telescope to probe the presence of a Galactic diffuse neutrino flux. This analysis is based on a recent model of cosmic ray propagation in the Galaxy, the KRAγ model. This model predict a neutrino flux particularly high and close to the sensitivity of the current neutrino telescopes. Two versions of this model exist corresponding to different cuts in the cosmic ray energy, one at 5 PeV/nucleon and an other one at 50 PeV/nucleon. A method of maximization of a likelihood function is used in order to account for the model characteristics in energy and space. The analysis has also been combined with the data of the IceCube experiment in order to exploit all the available data. Limits have been put on this model rejecting the version of the model with the 50 PeV cut and limiting the version with the 5 PeV cut to less than 1.2 times the predicted flux.A second analysis of gravitational wave signal follow-up by the ANTARES neutrino telescope is also presented in this work. The GW170817 gravitational wave signal results from the coalescence of a binary neutron star system. This second analysis aims at probing the presence of a neutrino flux coming from this event looking for neutrino events correlated in space and time. I took part to this analysis by adding the shower-like event sample. No event has been detected in correlation, limits have been put on the expected neutrino flux
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Caccianiga, Lorenzo. "Cosmic-ray astronomy at the highest energies with ten years of data of the Pierre Auger observatory." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066643/document.
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L'identification des sources de rayons cosmiques d'ultra-haute énergie (au-delà de 10^18 eV) constituerait une avancée majeure aussi bien dans le domaine de l'astrophysique que dans celui de la physique des particules. La difficulté principale dans la recherche de telles sources réside dans la perte de l'information directionnelle des rayons cosmiques les moins énergétiques. En effet, leur direction est sujette à des déviations d'amplitude inversement proportionnelle à leur énergie à cause des champs magnétiques qu'il traversent lors de leur propagation jusqu'à la Terre. D'autre part, pour des énergies supérieures à 4x10^(19)eV, l'interaction des rayons cosmiques avec le fond diffus cosmologique limite l'horizon de leurs sources à l'Univers proche (200 Mpc ou moins). Cette thèse a été effectuée au sein de l’observatoire Pierre Auger, le plus grand détecteur de rayons cosmiques de haute énergie. Elle est dédiée à l'étude, la sélection, la reconstruction, ainsi qu'à l'analyse des évènements de plus haute énergie. D'autre part, les particules de plus bas numéro atomique sont plus susceptibles de garder leur direction mais la composition des rayons cosmiques est inconnue à de telles énergies. Une méthode de sélection des événements les plus similaires aux protons a été élaborée et développée dans cette thèse pour étudier la possibilité de leur utilisation pour une "astronomie protons"Identifying the sources of the ultra-high energy cosmic rays (UHECRs, above 10^{18} eV), the most energetic particles known in the universe, would be an important leap forward for both the astrophysics and particle physics knowledge. However, developing a cosmic-ray astronomy is arduous because magnetic fields, that permeate our Galaxy and the extra-Galactic space, deflect cosmic rays that may lose the directional information on their sources. This problem can be reduced by studying the highest energy end of the cosmic ray spectrum. Indeed, magnetic field deflections are inversely proportional to the cosmic ray energy. Moreover, above 4x10^{19} eV, cosmic rays interact with cosmic photon backgrounds, losing energy. This means that the sources of the highest energy cosmic rays observed on Earth can be located only in the nearby universe (200 Mpc or less). The largest detector ever built for detecting cosmic rays at such high energies is the Pierre Auger Observatory, in Argentina. It combines a 3000 km^2 surface array of water Cherenkov detectors with fluorescence telescopes to measure extensive air showers initiated by the UHECRs. This thesis was developed inside the Auger Collaboration and was devoted to study the highest energy events observed by Auger, starting from the selection and reconstruction up to the analysis of their distribution in the sky. Moreover, since the composition at these energies is unknown, we developed a method to select proton-like events, since high Z cosmic rays are too much deflected by magnetic fields to be used for cosmic-ray astronomy
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Heinze, Jonas. "Ultra-high-energy cosmic-ray nuclei and neutrinos in models of gamma-ray bursts and extragalactic propagation." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21386.
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Utrahochenergetische kosmische Strahlung (ultra-high-energy cosmic rays -- UHECR) besteht aus ionisierten Atomkernen mit den höchsten Teilchenergien, die je gemessen wurden.
Zwar wurden die Quellen von UHECRs noch nicht eindeutig identifiziert, doch gibt es deutliche Anzeichen, dass sie extragalaktisch sind.
Um die Beobachtungen zu interpretieren, wird ein Modell der Wechselwirkungen mit Photofeldern sowohl in der Quelle als auch während der extragalaktischen Propagation benötigt.
Bei diesen Wechselwirkungen werden sekundäre Neutrinos erzeugt.
Diese Dissertation behandelt Modelle der Quellen von UHECRs und die damit verbundene Produktion von Neutrinos sowohl in den Quellen als auch während der Propagation.
Dafür wurde ein neuer Code, PriNCe, für die Propagation von UHECRs entwickelt. Dieser Code wird in einem umfangreichen Parameterscan für ein generisches Quellenmodell angewendet, welches mit dem Spektralindex, der maximalen Rigidität, der kosmologischen Quellenverteilung und der chemischen Komposition als freie Parameter definiert ist. Dabei wird der Einfluss von verschiedenen Photodisintegrations- und Luftschauermodellen auf die erwarteten Eigenschaften der Quellen demonstriert.
Der Fluss kosmogenischer Neutrinos, der sich daraus robust vorhersagen lässt, liegt außerhalb der Reichweite aller derzeit geplanten Neutrinodetektoren.
GRBs als mögliche Quellen von UHECRs werden im Multi-Collision Internal-Shock Modell simuliert, welches die Abhängigkeit der Strahlungsprozesse von den verschiedenen Dissipationsradien im Plasmajet berücksichtigt.
Für dieses Modell wird der Effekt demonstriert, den verschiedene Annahmen über die anfängliche Verteilung des Plasmajets und das hydrodynamische Modell auf die resultierende UHECR- und Neutrinosstrahlung haben.
Für den Gammastrahlenblitz GRB170817A, welcher zusammen mit einem Gravitationswellensignal beobachtet wurde, werden Vorhersagen für den Neutrinofluss und ihre Abhängigkeit vom Beobachtungswinkel gemacht.Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles observed in the Universe. While the astrophysical sources of UHECRs have not yet been uniquely identified, there are strong indications for an extragalactic origin. The interpretation of the observations requires both simulations of UHECR acceleration and energy losses inside the source environment as well as interactions during extragalactic propagation. Due to their extreme energies, UHECR will interact with photons in these environments, producing a flux of secondary neutrinos. This dissertation deals with models of UHECR sources and the accompanying neutrino production in the source environment and during extragalactic propagation. We have developed a new, computationally efficient code, PriNCe, for the extragalactic propagation of UHECR nuclei. The PriNCe code is applied for an extensive parameter scan of a generic source model that is described by the spectral index, the maximal rigidity, the cosmological source evolution and the injected mass composition. In this scan, we demonstrate the impact of different disintegration and air-shower models on the inferred source properties. A prediction for the expected flux of cosmogenic neutrinos is also derived. GRBs are discussed as specific UHECR source candidates in the multi-collision internal-shock model. This model takes the radiation from different radii in the GRB outflow into account. We demonstrate how different assumptions about the initial setup of the jet and the hydrodynamic collision model impact the production of UHECRs and neutrinos. Motivated by the multi-messenger observation of GRB170817A, we discuss the expected neutrino production from this GRB and its dependence on the observation angle. We show that the neutrino flux for this event is at least four orders of magnitude below the detection limit for different geometries of the plasma jet.
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Coste, Benoît. "Mesure et phénoménologie du rayonnement cosmique avec l'expérience CREAM." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00821110.
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Le rayonnement cosmique galactique nucléaire est composé de noyaux de différentes espèces et ses sources sont encore mal identifiées. Cette méconnaissance est en partie due au caractère diffusif de la propagation des noyaux dans les champs magnétiques dont la composante turbulente supprime toute information sur la position des sources. Dans le rayonnement cosmique, on distingue les noyaux pri- maires qui sont principalement créés puis accélérés près de leurs sources des noyaux secondaires, uniquement créés par spallation des primaires plus lourds. La mesure des rapports d'abondance se- condaire sur primaire permet d'étudier les processus de propagation et donc de remonter aux méca- nisme sources du rayonnement cosmique. Cette étude apporte de plus une meilleure compréhension de l'environnement astrophysique galactique. Ce travail nécessite une très bonne connaissance des sections efficaces d'interaction du rayonnement cosmique dans le milieu interstellaire qui régissent la modification des abondances lors de la propagation. La première partie de cette thèse est dédiée à la contrainte des paramètres de propagation du rayonnement cosmique galactique via l'étude des abondances des éléments du quartet (1H,2H,3He,4He). À partir d'une nouvelle estimation des sections efficaces, une analyse statistique a permis de démontrer le potentiel de ces éléments pour contraindre les modèles de propagation du rayonnement cosmique. Ces contraintes restent cependant limitées par la précision statistique des mesures actuelles et justifient la mise en œuvre de nouvelles expériences. La deuxième partie de cette thèse est dédiée à la mesure des abondances avec l'expérience CREAM, une expérience embarquée en ballon. Cette mesure nécessite l'identification des éléments dans le dé- tecteur, le calcul des efficacités des sous-détecteurs, la déconvolution des effets dus aux erreurs sur la mesure de l'énergie ainsi que la prise en compte des effets atmosphériques. Cette analyse des données du 3ième vol de CREAM a permis une estimation des abondances des éléments bore, carbone, azote et oxygène.
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Machado, Laura Paulucci. "Matéria de quarks (strangelets) de origem astrofísica e sua detecção por experimentos terrestres." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-26112008-100951/.
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A hipótese de que a matéria estranha de quarks (um plasma composto por quarks up, down e strange em quantidades aproximadamente iguais) é estável `a pressão nula vem sendo considerada há mais de vinte anos, tanto teoricamente quanto em experimentos específicos para sua eventual detecção. Se a matéria estranha é de fato estável, então poderia haver importantes implicações para a Astrofísica. Entre as mais estimulantes destas implicações está a possibilidade de conversão da matéria nuclear ordinária em matéria estranha no interior das estrelas de nêutrons devido ás altíssimas densidades ali encontradas. Processos tais como coalescência em binárias de estrelas de nêutrons e as próprias supernovas, eventos responsáveis pelo nascimento destas estrelas, poderiam ejetar estruturas finitas de matéria estranha, chamadas strangelets (equivalentes aos núcleos), no meio interestelar. Desta forma, strangelets estariam presentes entre os primários de raios cósmicos e seriam sujeitas a processos elementares análogos aos núcleos ordinários. Nesta Tese, as strangelets são estudadas desde os prováveis sítios para sua produção astrofísica, passando por interações com a matéria do meio interestelar, ate a chegada ás imediações terrestres. Estima-se o fluxo de strangelets de baixa energia que poderia ser mantido aprisionado na magnetosfera da Terra, bem como são estudados os processos de suas interações com componentes da atmosfera, com vistas às assinaturas observacionais então resultantes. Desta forma, são determinadas as características relevantes para a identificação destes exóticos por experimentos que testam o fluxo de raios cósmicos, ajudando na melhor compreensão das propriedades da matéria nuclear em alta densidade bariônica e baixa temperatura.The strange quark matter hypothesis, which states that a plasma composed of quarks up, down and strange in roughly equal amounts is absolutely stable at zero pressure, has been studied for more than twenty years, both theoretically and during searches for its detection in specific experiments. If strange quark matter is indeed stable, then there could be important implications for the field of Astrophysics. Among the most stimulating ones is the possibility of conversion of ordinary nuclear matter in strange quark matter in the interior of neutron stars due to the extremely high densities reached in the core of these compact objects. Processes such as the merger in neutron star binaries systems and supernovae themselves, responsible for the birth of these stars, may eject lumps of strange quark matter, termed strangelets, in the interstellar medium. In this way, strangelets may be present among the cosmic ray flux and be subjected to elementary processes much in the same way as ordinary nuclei. In this Thesis, strangelets are studied from their likely astrophysical production sites, passing through the interstellar medium until they reach the Earth neighborhood. Estimates of the low energy flux of strangelets that could be trapped in the terrestrial magnetosphere are given. Also, the interaction of these particles with components in the Earth atmosphere are studied with the aim of providing better understanding of the resulting observational signatures. It allows the determination of the relevant characteristics for the identification of these exotics by experiments testing the cosmic ray flux, helping to better understand the properties of nuclear matter at high densities and low temperatures.
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Meyhandan, Rishi. "Search for ultra high energy radiation from astrophysical sources." Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phm6137.pdf.
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Blanco-Pillado, José Juan. "Topological defects and ultra-high energy cosmic rays /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2001.
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Thesis (Ph.D.)--Tufts University, 2001.Adviser: Alexander Vilenkin. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 108-114). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Serpico, Pasquale Dario. "High energy astroparticle physics with cosmic rays and neutrinos." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980374863.
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Brobeck, Elina Stone Edward McKeown R. D. "Measurement of ultra-high energy cosmic rays with CHICOS /." Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-10192008-143041.
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Lundanes, Ingvild Olsen. "The propagation and energy losses of ultra high energy cosmic rays." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12654.
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This project investigates the propagation of ultra-high energy cosmic raynuclei and protons. A simulation of the propagation subjecting the particlesto energy losses due to cosmological redshift as well as interactions with theextra-galactic background radiation seeks to find the initial conditions at thesource which give the best results on Earth compared to the observations ofthe Pierre Auger Observatory (PAO).The results agree with previous works of the same kind that a chemicalcomposition of medium-weight fits the observed air shower data best. Thestarting conditions which gave the best results for the air shower characteristics
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Gagnon, Olivier. "Limits on Lorentz non-invariance from high energy cosmic rays." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82235.
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We put strong constraints on Lorentz violation by studying the inner structure of highly energetic protons. Our work is in direct continuation of previous analysis based on dimensions 4, 5 and 6 Lorentz violating operators. Our original contribution is due to the study of the inner structure of hadrons and their relation with Lorentz violating operators. The strength of the constraints arising from this new analysis should discourage us to propose new general theories that are Lorentz violating.
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Barbot, Cyrille. "Super-heavy X-particle decay and ultra-high energy cosmic rays." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969379846.
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Khanin, Alexander. "Bayesian methods for the analysis of ultra-high-energy cosmic rays." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/42034.
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The origins of ultra-high-energy cosmic rays (UHECRs) are one of the open puzzles of astrophysics. A number of plausible candidates, such as active galactic nuclei (AGNs) have been discussed, but no clear consensus has been reached. One way to assess the different hypotheses is by analyzing the UHECR arrival directions. Recently, a small number of studies have begun applying Bayesian methodologies to this problem, forming the first steps in the development of a comprehensive Bayesian framework for the study of UHECRs. In this work, we have developed two Bayesian methods to study this question, and have applied them to UHECRs from the Pierre Auger Observatory (PAO). The first method was a Bayesian approach to studying the catalogue-independent clustering of UHECRs. Previously, this had been difficult as there is no well motivated clustered model that can be used in a Bayesian model comparison. We have resolved this difficulty by developing a multi-step approach that derives such a model from a sub-set of the data. This approach could have broad applications for anisotropy searches in other areas of astronomy. Our results were consistent with both isotropic and clustered models. The second was a Bayesian method that was aimed to find associations between UHECR arrival directions and source catalogues. It was an extension of a previous Bayesian study, but analyzed a greater data set, used a more refined UHECR model, and was generalized to be applicable to a greater variety of source catalogues. Our results were broadly consistent with previous work, with the purely isotropic UHECR models being disfavoured for reasonable parameter ranges. It will be of great interest to apply our methods to samples of greater size. The extended UHECR samples that will be available in the near future should be sufficient for our methods to determine the origins of the UHECRs.
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Rodrigues, Xavier. "Blazars as Sources of Neutrinos and Ultra-high-energy Cosmic Rays." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20610.
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Der Ursprung ultra-hochenergetischer kosmischer Strahlung (UHECRs) ist immer noch unbekannt. Neutrinoteleskope wie IceCube messen einen Fluss hochenergetischer astrophysikalischer Neutrinos, dessen erwarteter Ursprung Wechselwirkungen kosmischer Strahlung (CR) ist. Jedoch scheinen die Ankunftsrichtungen der beobachteten Neutrinos nicht signifikant mit den Koordinaten bekannter, hochenergetischer astrophysikalischer Quellen zu korrelieren. Wir tragen zum Verständnis dieses Problems durch die Untersuchung von Blazaren, eine Klasse aktiver Galaxienkerne, bei. Motiviert durch Hinweise, dass ein Teil der UHECRs schwerer als Protonen ist, modellieren wir die Wechselwirkungen einer Population beschleunigter Kerne mit den umgebenden Photonfelder in Blazaren. Wir folgern, dass in Blazaren niedriger Luminosität beschleunigte CRs nicht effizient wechselwirken. In hellen Blazaren sind photo-hadronische Wechselwirkungen effizient, was zu starker Neutrinoproduktion und zur Entwicklung einer nuklearen Kaskade führt. Wir berechnen die Neutrinoemission der gesamten Verteilung von Blazaren, und folgern, dass eine Population niedriger Luminosität, die derzeit nicht beobachtet, aber theoretisch erwartet wird, den gesamten IceCube-Fluss bei den höchsten Energien erklären kann. Weiterhin modellieren wir den Blazar TXS 0506+056, aus dessen Richtung ein Neutrino während einer Phase erhöhter elektromagnetischer Aktivität detektiert wurde. Wir testen die Hypothese, dass ein Signal von 13+/-5 Neutrinos, die in IceCube aus der selben Richtung im Jahr 2014-15 gemessen wurden, von der selben Quelle stammt. Unser Modell kann höchstens 5 Ereignisse erklären. Schließlich untersuchen wir das erste beobachte Ereignis verschmelzender Neutronensterne, GW170817, als CR-Beschleuniger. Wir modellieren die Quelle und zeigen, dass Radio- und Röntgenmessungen strikte Beschränkungen der magnetischen Feldstärke nach sich ziehen. Wir zeigen, dass diese Quelle in der Lage ist, CRs zu emittieren.The origin of ultra-high-energy cosmic rays (UHECRs) is still unclear. Neutrino telescopes like IceCube have observed a flux of high-energy cosmic neutrinos, expected to originate in cosmic ray (CR) interactions. However, their arrival directions do not statistically correlate with the positions of known high-energy astrophysical sources. In this thesis we explore blazars, a class of active galaxies, as potential UHECR accelerators. Motivated by evidence that a fraction of the UHECRs are heavier than protons, we model the interactions of CR nuclei with the photon fields present in blazars, in order to estimate the emitted neutrino and UHECR spectrum. We conclude that in dim blazars, accelerated CRs do not interact efficiently due to the low photon density, but instead escape the source unscathed. In bright blazars, photo-hadronic interactions are more efficient, leading to abundant production of neutrinos and lighter nuclei. We use this model to quantify the neutrino emission from the entire cosmological blazar population. We conclude that low-luminosity blazars currently unobserved but expected theoretically, can explain the entire IceCube flux at the highest energies. We then focus on blazar TXS 0506+056, from whose direction a neutrino was recently detected during an electromagnetic flaring state. We test the hypothesis that a signal of 13+/-5 neutrinos observed by IceCube from the same direction in 2014-15 may have originated in the same source. Given the constraints from multi-wavelength observations, this model can explain at most 5 neutrino events. Finally, we study the remnant of the first neutron star merger ever observed, object GW170817. We model the particle interactions in the source and show that multi-wavelength observations can provide a constraint on the magnetic field strength. We estimate that this source may be an efficient CR emitter, which shows the importance of future multi-messenger observations to better constrain this source type.
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Smith, Nigel James Telfer. "A search for ultra high energy gamma ray sources from the South Pole." Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291023.
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Medina, Andres Alberto. "Reconstruction of Xmax and Energy from 3 -- 100 PeV using 5 Years of Data From IceTop and IceCube and its Applications." The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1617101771880381.
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Masdjed, Hussein Farrashbashi. "Search for tachyons in cosmic rays at sea level." Thesis, Durham University, 1986. http://etheses.dur.ac.uk/7194/.
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Cossavella, Fabiana. "Measurements of high energy cosmic rays above 10 PeV with KASCADE-Grande." Eggenstein-Leopoldshafen Forschungszentrum Karlsruhe GmbH, 2009. http://d-nb.info/999765329/34.
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Schumacher, Lisa Johanna [Verfasser], Christopher Henrik V. [Akademischer Betreuer] Wiebusch, and Antoine [Akademischer Betreuer] Kouchner. "Search for the common sources of high-energy cosmic neutrinos and ultra-high-energy cosmic rays / Lisa Johanna Schumacher ; Christopher Wiebusch, Antoine Kouchner." Aachen : Universitätsbibliothek der RWTH Aachen, 2021. http://d-nb.info/1238365329/34.
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Dundovic, Andrej [Verfasser], and Günter [Akademischer Betreuer] Sigl. "On Anisotropies of Ultra-high Energy Cosmic Rays / Andrej Dundovic ; Betreuer: Günter Sigl." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2018. http://d-nb.info/1162275243/34.
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Mottram, M. J. "A search for ultra-high energy neutrinos and cosmic-rays with ANITA-2." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1344072/.
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The ANtarctic Impulsive Transient Antenna (ANITA) experiment is a balloon-borne array of radio antennas designed to search for ultra-high energy neutrinos by observing the Antarctic ice sheet for radio emission that is expected to arise as a result of the neutrinos’ interaction. ANITA is further able to detect radio emission that arises when ultra-high energy cosmic-rays interact in the Earth’s atmosphere. The second flight of the experiment, ANITA-2, took place in 2008-09 over 31 days. This thesis describes an analysis of the ANITA-2 dataset and presents results from searches for ultra-high energy neutrinos and cosmic-rays. No statistical evidence of emission from neutrino interactions is observed, with two candidate events discovered on a background of 1:13 \pm 0:27. A limit on the diffuse flux of ultra-high energy neutrinos is presented, further model-independent and model-dependent flux limits on selected active galactic nuclei are calculated. Four isolated and one non-isolated cosmic-ray candidates are discovered. The identity of the isolated candidates as cosmic-ray-induced radio emission is confirmed through correlation between observed and expected emission polarisation.
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Oikonomou, F. "Constraining the sources of ultra-high energy cosmic rays with multi-messenger data." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1450249/.
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Ultra-high energy cosmic rays (UHECRs) are cosmic rays with energy exceeding 10¹⁸ electronvolts. The sources of these particles remain unknown despite decades of research. This thesis presents a series of studies aimed at constraining the sources of UHECRs both directly by studying their observed arrival directions and indirectly through their expected secondary gamma-ray signatures. An analysis of the arrival direction distribution of the highest energy cosmic rays detected at the Pierre Auger Observatory is presented. The aim of the study was to determine whether the arrival directions of observed UHECRs follow the distribution of nearby extragalactic sources, which is expected if UHECRs are light nuclei of extragalactic origin. A departure from isotropy at the 95% level is observed but no clear correlation with the extragalactic matter distribution is found. The sensitivity of upcoming UHECR experiments, with an order of magnitude higher annual exposure than current experiments, to the expected UHECR anisotropy has been investigated through simulations. It is shown, that with five years of data from such a detector an anisotropy should be detectable at the 99% level as long as the composition is proton dominated. In a scenario where the UHECR source distribution is strongly clustered, similar to the distribution of galaxy clusters, an anisotropy at the 99.9% level is expected even if the fraction of protons at the highest energies is as low as 30%. Constraints on the sources of UHECRs may also come from the secondary particles that UHECRs produce during their propagation. A study of the expected secondary gamma-ray signatures of UHECR accelerators embedded in magnetised environments is presented. The secondary gamma-ray emission expected in this model is shown to be consistent with the spectra of a number of extreme blazars. It is shown that this model is more robust to variations of the overall extragalactic magnetic eld strength than other proposed scenarios, which is appealing in view of the large uncertainty surrounding the strength and con guration of extragalactic magnetic fi elds.
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Lang, Rodrigo Guedes. "Effects of Lorentz invariance violation on the ultra-high energy cosmic rays spectrum." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-13042017-143220/.
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Relativity is one of the most important and well tested theories and Lorentz invariance is one of its pillars. Lorentz invariance violation (LIV), however, has been discussed in several quantum gravity and high energy models. For this reason, it is crucial to test it. Several tests, both terrestrial and astrophysical, have been performed in the last years and provide limits on the violation. This work takes part in these efforts and discuss the possibility of testing LIV with ultra-high energy cosmic rays (UHECRs). The effects of LIV in their propagation and the resulting changes in the spectrum of UHECRs are obtained and compared to the experimental data from the Pierre Auger Observatory. An analytical calculation for the inelasticity in the laboratory frame with LIV of any a + b → c + d interaction is presented and used to obtain the phase space and the energy losses of the pion production for protons, the photodisintegration for nuclei and the pair production for photons with LIV. A parametrization for the threshold energy of the photodisintegration with LIV is also proposed. The main effect seen is a decrease in the phase space and a resulting decrease in the energy loss. These changes have been implemented in Monte Carlo propagation codes and the resulting spectra of protons, nuclei and photons on Earth have been obtained and fitted to the data from the Pierre Auger Observatory. It is shown that upper limits on the photon LIV coefficient can be derived from the upper limits on the photon flux from the Pierre Auger Observatory.Relatividade é uma das mais importantes e bem testadas teorias e a invariância de Lorentz é um de seus pilares. A violação da invariância de Lorentz (VIL), todavia, tem sido discutida em diversos modelos de gravidade quântica e altas energias. Por tal motivo, é crucial testá-la. Diversos testes, tanto terrestres quanto astrofísicos, foram realizados nos últimos anos e fornecem limites na violação. Este trabalho se insere nesses esforços e discute a possibilidade de testar VIL com raios cósmicos de altíssima energia. Os efeitos da VIL em sua propagação e as consequentes mudanças no espectro de raios cósmicos de altíssima energia são obtidos e comparados com os dados experimentais do Observatório Pierre Auger. Um cálculo analítico para a inelasticidade no referencial do laboratório com VIL para qualquer interação da forma a + b → c + d é apresentado e usado para obter o espaço de fase e as perdas de energia para a produção de píons para prótons, a fotodesintegração para núcleos e a produção de pares para fótons com VIL. Uma parametrização para o limiar de energia da fotodesintegração com VIL também é proposta. O principal efeito observado é uma diminuição no espaço de fase e uma consequente diminuição nas perdas de energia. Tais mudanças foram implementadas em códigos de Monte Carlo para a propagação e os espectros resultantes para prótons, núcleos e fótons na Terra foram obtidos e ajustados aos dados do Observatório Pierre Auger. É mostrado que limites superiores nos coeficientes de VIL para o fóton podem ser deduzidos dos limites superiores para o fluxo de fótons do Observatório Pierre Auger.
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Cossavella, Fabiana [Verfasser]. "Measurements of high energy cosmic rays above 10 PeV with KASCADE-Grande / Fabiana Cossavella." Eggenstein-Leopoldshafen : Forschungszentrum Karlsruhe GmbH, 2009. http://d-nb.info/999765329/34.
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Morejon, Leonel. "New Interaction Models of Ultra-high-energy Cosmic Rays from a Nuclear Physics Approach." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22585.
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Der Ursprung der ultrahochenergetischen kosmischen Strahlung (UHECRs) benötigt Modelle der photonuklearen kosmischen Strahlungsinteraktionen. In dieser Arbeit stelle ich Modelle vor, die drei Aspekte der Modellierung der Hochenergie-Astronuklearphysik verbessern: die Photomesonenproduktion durch Kerne der kosmischen Strahlung, die schwerer als Protonen sind, die Gammastrahlenemission von instabilen Kernen, die durch den Photodisintegrationsprozess der kosmischen Strahlung erzeugt werden, und die Simulation der extragalaktischen Ausbreitung von Kernen, die schwerer als Eisen sind (sogenannte superschwere Isotope). Das Photomesonenmodell ist das erste in der Literatur, das über das einfache Prinzip der Nukleonen-Superposition hinausgeht. Es liefert eine detailliertere Beschreibung der inelastischen Wirkungsquerschnitte und des emittierten Spektrums von Sekundärteilchen, einschließlich Isotopen und Pionen, die zu Photonen und Neutrinos führen. Die Auswirkungen des Modells werden in Simulationen von Gammastrahlenausbrüchen und Gezeitenstörungsereignissen gezeigt, und es beeinflusst signifikant die hochenergetische Neutrinoemission, die chemische Zusammensetzung und das Spektrum der emittierten UHECRs. Das zweite Modell beschreibt die Photoproduktion aus den De-Exzitationen und Zerfällen instabiler Kerne, die aus dem Photozerfall der kosmischen Strahlung in Wechselwirkung mit astrophysikalischen Photonen resultieren sollen. Ihre Wirkung wird am Photoemissionsspektrum des Kerns von Centaurus A veranschaulicht und mit ähnlichen Arbeiten verglichen, mit denen es Unstimmigkeiten gibt. Schließlich wird der Photodesintegration von UHECR überschweren Kernen diskutiert. Eine Wechselwirkungstabelle wird unter Verwendung von Querschnitten aus TALYS konstruiert, und die Wechselwirkungsraten werden im Zusammenhang mit der extragalaktischen Ausbreitung berechnet. Überschwere Kerne breiten sich in bestimmten Energiebereichen weiter aus als leichtere Kerne.The origin of the ultra-high-energy cosmic rays (UHECRs) is still unknown. Photonuclear interactions of cosmic rays are key to understanding this problem in a multimessenger context. Nuclear physics insights are crucial in building accurate models to interpret the data that indicates UHECR can be heavier than protons. This thesis presents models that improve three aspects of high-energy astronuclear physics modelling: photomeson production by cosmic-ray nuclei heavier than protons, gamma-ray emission from unstable nuclei created by the photodisintegration of cosmic rays, and the simulation of extragalactic propagation of nuclei heavier than iron (so-called superheavy isotopes). The photomeson model is the first in the literature to go beyond the simple principle of nucleon superposition. It provides a more accurate description of the inelastic cross sections, and the emitted spectrum of secondary particles, including isotopes and pions which lead to photons and neutrinos.The model’s impact is shown in simulations of gamma-ray bursts and tidal disruption events, and it affects significantly the high-energy neutrino emission, the chemical composition and the spectrum of the emitted UHECRs. The second model describes photoproduction from de-excitations and decay of unstable nuclei, which are expected to be produced in photo-disintegration of cosmic rays interacting with astrophysical photons. Its impact is illustrated in the photo-emission from the core of the Centaurus A and compared to similar works with which is in disagreement. This supports the need for sufficiently accurate models. Lastly, the photodisintegration of UHECR superheavy nuclei is discussed. An interaction table is produced with cross sections obtained from TALYS and the interaction rates computed in the context of extragalactic propagation. Superheavy nuclei propagate further than lighter nuclei in certain energy ranges. The models developed are publicly available as open-source software.
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Zeng, Houdun, Yuliang Xin, Siming Liu, J. R. Jokipii, Li Zhang, and Shuinai Zhang. "EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623101.
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Multi-wavelength observations of mature supernova remnants (SNRs), especially with recent advances in gamma-ray astronomy, make it possible to constrain energy distribution of energetic particles within these remnants. In consideration of the SNR origin of Galactic cosmic rays and physics related to particle acceleration and radiative processes, we use a simple one-zone model to fit the nonthermal emission spectra of three shell-type SNRs located within 2 degrees on the sky: RX J1713.7-3946, CTB 37B, and CTB 37A. Although radio images of these three sources all show a shell (or half-shell) structure, their radio, X-ray, and gamma-ray spectra are quite different, offering an ideal case to explore evolution of energetic particle distribution in SNRs. Our spectral fitting shows that (1) the particle distribution becomes harder with aging of these SNRs, implying a continuous acceleration process, and the particle distributions of CTB 37A and CTB 37B in the GeV range are harder than the hardest distribution that can be produced at a shock via the linear diffusive shock particle acceleration process, so spatial transport may play a role; (2) the energy loss timescale of electrons at the high-energy cutoff due to synchrotron radiation appears to be always a bit (within a factor of a few) shorter than the age of the corresponding remnant, which also requires continuous particle acceleration; (3) double power-law distributions are needed to fit the spectra of CTB 37B and CTB 37A, which may be attributed to shock interaction with molecular clouds.
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Decoene, Valentin. "Sources and detection of high-energy cosmic events." Thesis, Sorbonne université, 2020. http://www.theses.fr/2020SORUS028.
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Ces dernières années, de nouvelles classes de sources (sursaut radio rapide, fusion d’étoiles à neutron, etc…) ont été découvertes grâce aux progrès de l’astronomie photonique à toutes les longueurs d’ondes. Avec l’avènement de l’astronomie multi-messager, nous avons été capable de les scruter à travers les rayons cosmiques, les neutrinos, les photons et les ondes gravitationnelles. La première partie de cette thèse est dédiée à l’étude des neutrinos de hautes et ultra hautes énergies. Depuis la découverte en 2013 par IceCube d’un flux diffus de neutrinos, deux questions centrales sont apparues : quelles sont les sources de ce flux diffus, et pouvons-nous détecter des neutrinos à plus haute énergie encore (>PeV). Afin d’aider à répondre à ces questions, nous présentons en premier un modèle d’émission de neutrinos de hautes énergies résultant de la fusion d’étoiles à neutron. Nous examinons ensuite la possibilité de radio détecter les gerbes atmosphériques induites par les neutrinos d’ultra hautes énergies, à travers une étude sur l’optimisation d’un tel détecteur, et une analyse détaillée des caractéristiques du signal et de sa reconstruction. La deuxième partie de cette thèse est dédiée à l’étude des sursauts radio rapides (FRB). Ces pulses radio, brefs, cohérents et nombreux, n’ont pas été identifiés encore et de nombreuses inconnues expérimentales persistent. En premier, nous proposons un modèle de source expliquant les taux de sursauts observés. Enfin, nous présentons un programme observationnel, conduit par l’instrument NenuFAR, situé à la Station de Radio Astronomy de Nançay, dédié à l’observation des FRB aux basses fréquences (100MHz)In the last decade, new classes of sources (fast radio burst, binary neutron star mergers, ...) have been discovered thanks to progress in photon astronomy at all wavelengths. With the advent of multimessenger astronomy, we were able to scrutinize them with cosmic rays, neutrinos, photons and gravitational waves. The first part of this thesis is dedicated to the study of the high-energy and ultra-high energy neutrinos. Since the discovery in 2013 by IceCube of a diffuse neutrino flux, two major questions have been raised: what are the sources of this diffuse flux, and can we detect neutrinos at higher energies (> PeV). To help answering these questions, we first present a model of high-energy neutrino emissions from neutron star mergers. We then examine the radio detection of extensive air showers induced by ultra-high-energy neutrinos, with a study of a detector optimisation, and a detailed analysis of the signal characteristics and develops a reconstruction procedure. The second part of this thesis is dedicated to the study of the fast radio bursts. These brief, coherent and numerous radio pulses, have not been identified yet and many experimental unknowns remain. We first propose a source model focusing on the question of the pulses rates. Finally, we present an observational program conducted with the NenuFAR instrument, located in the Nançay Radio Astronomy Station, dedicated to the detection and the characterisation of FRBs at low frequency (<100MHz)
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Räihä, T. (Tomi). "Analysis tools for the EMMA experiment." Doctoral thesis, University of Oulu, 2012. http://urn.fi/urn:isbn:9789514299469.
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Abstract
Cosmic rays are energetic particles traversing space that bombard Earth's atmosphere frequently and produce vast particle showers while interacting with air nuclei. The origin and composition of high-energy cosmic rays in the knee region (1015 - 1016 eV) of the cosmic-ray energy spectrum remain unclear despite of novel detection and analysis methods used in various surface and underground experiments. The understanding of the knee has improved from its first detection but still there is notable deviation in results between experiments depending on the used detection methods.
The aim of the underground cosmic-ray experiment EMMA (Experiment with Multi-Muon Array) is to shed more light on the origin of the knee. EMMA is based on the idea to measure the lateral shape of high-energy muon component produced in cosmic-ray initiated particle showers on an event-by-event basis, that is, separately for each shower, offering a unique way to study the composition of cosmic rays in the knee region.
The present work comprises the design, development and implementation of a comprehensive set of analysis tools for the EMMA experiment. It includes the development of the simulation program to generate realistic event data, the track reconstruction program ETANA to reconstruct hits and tracks in detector stations, the visualisation program EmmaEve to scan events, the graphical monitoring program EmmaDiagnosticsGUI to control the functionality of detectors on-line, the efficiency monitoring program to control chamber efficiencies in three-layer stations and the design of the EMMA database to store reconstruction results. Especially the design and tests of ETANA form the backbone of the present work as its optimised performance is crucial for the analysis of EMMA data.
Furthermore, in the present work the influence of rock overburden above EMMA on the properties of high-energy muons is investigated by detailed simulations. The reconstruction of hits in drift chambers is studied with measured data including the estimation of the quality of reconstructed hits, the functionality of hit formation procedure and the influence of afterpulses on hit reconstruction. The validity of simulated data that are generated by the EMMA event generation program is evaluated by comparing simulated and measured data with each other. Finally, synergy benefits between the EMMA and ALICE experiments are discussed, which are both underground experiments but different in nature.
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Viberg, Fredrik. "Advanced algorithms for Ultra-High-Energy Cosmic Ray Detection with the EUSO-TA Experiment." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-313.
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Cosmic rays at energies 10^18 eV and above are known as Ultra High Energy Cosmic Rays (UHECR). UHECR are charged particles that are accelerated by the biggest accelerators in our universe. Candidate accelerators generating these UHECR are super novas, black holes and neutron stars. But where and what these intergalactic accelerators is at large still unknown. One of the experiments in the forefront of research in this eld is JEM-EUSO, a planed space based telescope for detecting UHECR particles as they enter Earth's atmosphere. Made possible by the advances in photon detectors and light weighted Fresnel lenses. A ground based path nder experiment was carried out in 2015 called EUSO-TA to test the optics and photomultiplier technologies. When the UHECR enters the atmosphere it collides with the atoms generating a number of secondary particles which in turn interacts with other atoms in the atmosphere generating a cascade of secondary particles. These trails are known as Extensive Air Showers (EAS). Mostly electrons are generated and in turn they excites the nitrogen atoms in the atmosphere which generate a isotropic characteristic uorescence light. The JEM-EUSO telescope is designed to detect and measure the photon ux. From the photon ux it will be able to estimate the energy of the initial UHECR. JEM-EUSO will cover the largest area of EAS search and increase statistics of UHECR data. This thesis describes the method and development of algorithms made for EAS analysis and detection based on EUSO-TA data. A simulation of EUSO-TA focal surface was developed, simulating background, stars and EAS. The algorithms developed involves a background subtracting lter, line detection using Hough transform and a neural network for decision making. The Hough transform is used in computer vision and is a method used to detect lines in the pictures. It successfully identi ed both simulated and captured UHECR incoming direction with small errors. Neural network are a machine learning method used classi cation and regression problems. With the use of know example data simulated or real captured data a neural network can without explicit programing it, adjust its parameters to t the data. Based on method called supervised learning. The algorithms was programed in Python and using ROOT software to build the neural network. The resulting algorithm was able to successfully detect simulated data. Test on the EUSO-TA captured data shows a promising result but has to be developed and tested further.
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Heimann, Philipp [Verfasser]. "A test for the existence of protons in ultra-high energy cosmic rays / Philipp Heimann." Siegen : Universitätsbibliothek der Universität Siegen, 2018. http://d-nb.info/117520546X/34.
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Peron, Giada [Verfasser], and Felix [Akademischer Betreuer] Aharonian. "Probing the Spatial and Spectral Distribution of Galactic Cosmic Rays with High-Energy Gamma-Rays / Giada Peron ; Betreuer: Felix Aharonian." Heidelberg : Universitätsbibliothek Heidelberg, 2021. http://d-nb.info/1225938627/34.
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