Dissertations / Theses on the topic 'Point source search'
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Tummey, Steven Peter. "A search for diffuse and point source emission of UHE gamma rays using muon content selected EAS." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336196.
Full textCurland, Alexander Biron von. "Search for atmospheric muon-neutrinos and extraterrestric neutrino point sources in the 1997 AMANDA-B10 data." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2002. http://dx.doi.org/10.18452/14743.
Full textAbstract The young field of high energy neutrino astronomy can be motivated by the search for the origin of the charged cosmic rays. Large astrophysical objects like AGNs or supernova remnants are candidates to accelerate hadrons which then can interact to eventually produce high energy neutrinos. Neutrino-induced muons can be detected via their emission of Cherenkov light in large neutrino telescopes like AMANDA. More than 10^9 atmospheric muon events and approximately 5000 atmospheric neutrino events were registered by AMANDA-B10 in 1997. Out of these, 223 atmospheric neutrino candidate events have been extracted. This data set contains approximately 15 background events. It allows to confirm the expected sensitivity of the detector towards neutrino events. A second set containing 369 events (approximately 270 atmospheric neutrino events and 100 atmospheric muon events) was used to search for extraterrestrial neutrino point sources. Neither a binned search, nor a cluster search, nor a search for preselected sources gave indications for the existence of a strong neutrino point source. Based on this result, flux limits were derived. Assuming E^-2 neutrino spectra, typical flux limits for selected sources of the order of 10^-14 cm^-2 s^-1 for muon fluxes and 10^-7 cm^-2 s^-1 for neutrino fluxes have been obtained.
Pinat, Elisa. "The IceCube Neutrino Observatory: search for extended sources of neutrinos and preliminary study of a communication protocol for its future upgrade." Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/253046.
Full textFrench Version: Quand les humains ont commencé à regarder le ciel étoilé, l’astronomie est née. Les photons émis par les étoiles voyagent parfois des milliards d’années lumière avant d’atteindre nos yeux, et c’est grâce à l’étude de ce flux de photons que l’on peut déduire les propriétés des étoiles mêmes. Au lieu des photons, l’Observatoire IceCube, situé au Pôle Sud, a pour but de détecter des neutrinos :il espère éclairer le mystère encore non résolu de l’accéleration et des mécanismes de production des rayons cosmiques, ainsi que des phénomènes les plus énergétiques de l’Univers. Au moment où ce document a été rédigé, IceCube a démontré l’existence d’un flux de neutrinos astrophysiques avec une signification statistique excédant sept sigmas. Cependant, le flux de neutrinos astrophysiques observé ne montre aucun regroupement directionnel significatif ni une évidence d’association avec aucune source connue à l’heure actuelle. De plus, les derniers résultats fournis par les analyses de sources ponctuelles de la collaboration IceCube ne montrent non plus aucun regroupement. Il est donc important d’étendre ces recherches vers des typologies de sources différentes pour maximiser le potentiel de son découverte. Dans la première partie de ce travail nous présentons une analyse de source étendue basée sur sept années de données d’IceCube, ce qui rajoute trois ans de données au travail précédemment publié tout en mettant en oeuvre une nouvelle formulation de maximum de vraisem- blance. Comme les extensions de sources potentielles ne sont pas connues à priori, cinq extensions différentes ont été considérées, de 1° à 5°. Aucun regroupement significatif n’a été observé sur aucune des cartes. La capacité d’IceCube de consolider l’astronomie neutrino en découvrant des sources de neutrinos est limitée par le nombre de neutrinos cosmiques mesuré. Malgré la découverte susmentionnée d’un flux astrophysique, les études détaillées de spectre ainsi que les recherches de sources spécifiques pour ce type de signal demeurent un défi, à cause de la limitation de taille disponible des échantillons avec l’instrument IceCube. Par conséquent, une expansion considérable du détecteur actuel, IceCube Gen2, est promue :elle inclut l’instrumentation d’un volume de 10 km3, apte à fournir une augmentation importante des échantillons de neutrinos de toutes les saveurs. Non seulement le hardware sera mis à niveau, mais de nombreux autres systèmes subiront des améliorations, comme les infrastructures de communication et de timing. Un nouveau système de communication a été étudié et est présenté dans la deuxième partie de ce document. Le Binary Phase Shift Keying (BPSK), la technique de modulation numérique la plus simple, a été étudiée comme technique potentielle pour IceCube Gen2.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Altmann, Simon David. "Search for TeV neutrinos from point-like sources in the southern sky using four years of IceCube data." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://dx.doi.org/10.18452/17715.
Full textThere are accelerators in the universe that can accelerate charged particles (cosmic rays) to very high energies. Many questions regarding these accelerators are still open. Gamma rays and neutrinos are particles expected from sites of cosmic ray acceleration and can be used to study the environment and acceleration mechanisms of these sites. While sources for both galactic and extra-galactic gamma rays have been observed, it is often unclear whether these gamma rays are by-products of cosmic ray acceleration. This ambiguity does not exist for neutrinos. An astrophysical neutrino flux has been measured by the IceCube detector. Single sources have not been resolved yet. The part of the sky visible from the southern hemisphere hosts many galactic sources observed in GeV and TeV gamma-rays. Detection of neutrinos from these sources would identify them as acceleration sites and lead to a better understanding of the environment of the acceleration sites and the acceleration mechanisms. However, this is difficult due to the vast background of atmospheric muons also detected in the IceCube detector. For this thesis, a data selection was developed that reduces this background by using parts of the detector as veto. This selection focuses on the selection of muon-tracks from muon-neutrino interactions inside the detector volume. The direction and the energy-profile of these tracks can be reconstructed. This information is used to search for potential sources using an unbinned likelihood method. This analysis uses data taken between 2011 and 2015. In contrast to earlier IceCube analyses this analysis is optimized for energies between a few TeV and 100 TeV and improves the sensitivity of the detector for a point-like source by factor of two (or better) in this energy range. Results for a list of 96 sources observed in TeV gamma-rays and a sky-scan are presented. No significant overfluctuation has been observed and limits on the neutrino emission of the sources are given.
Menne, Thorben [Verfasser], Wolfgang [Akademischer Betreuer] Rhode, and Bernhard [Gutachter] Spaan. "Stacking point source search for a neutrino contribution at 22 track-like HESE positions using six years of IceCube data / Thorben Menne ; Gutachter: Bernhard Spaan ; Betreuer: Wolfgang Rhode." Dortmund : Universitätsbibliothek Dortmund, 2018. http://d-nb.info/1175205168/34.
Full textHeijboer, Adriaan Jacob. "Track reconstruction and point source searches with ANTARES." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/77461.
Full textStachyra, Andrew Lawrence. "A search for astrophysical point sources of neutrinos with Super-Kamiokande /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/9810.
Full textAlba, José Luis Bazo. "Search for steady and flaring astrophysical neutrino point sources with the IceCube detector." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16240.
Full textHigh energy neutrino astronomy relies on the predictions of neutrino fluxes coming from astrophysical objects, for example active galactic nuclei. In these models, neutrinos and gamma-rays are produced in hadronic processes, which require the acceleration of protons to very high energies. Since neutrinos hardly interact and travel towards Earth undeflected by magnetic fields, they can point back to their sources. IceCube, located at the South Pole, is a large volumen detector for high energy neutrinos. In this work, data from two partial configurations of IceCube (22 and 40 strings) are analyzed. The data cover 651 days, from 2007 to 2009, and consist mostly of atmospheric muon neutrinos in the Northern sky and high energy atmospheric muons in the Southern sky. A time integrated search for neutrino point sources in the Northern sky was developed and applied to an event sample obtained for the best sensitivity, with IceCube 22-string. The search was performed on pre-selected sources and the whole hemisphere was scanned. No evidence of a neutrino signal was found. In order to enhance the flare detection probability, an untriggered time dependent search that looks for neutrino events clustering in time from specific sources in the entire sky was developed. This search was motivated by neutrino-photon correlations and the observations of flaring objects in gamma-rays, but focuses only on the neutrino data, covering a wide range of possible flare durations. The search method was expanded from a binned approach to a newly developed unbinned likelihood method, improving the results by 5-25%. Moreover, for the first time the Southern sky was analyzed with a time dependent method. A source selection criteria was developed defining two lists of variable astrophysical sources, for IceCube 22 and 40-string. The results were compatible with background fluctuations for all sources tested. Therefore, upper limits on the neutrino fluence from these sources are presented.
Hauschildt, Tonio. "Search for cosmic point sources of high energy neutrinos with the AMANDA-II detector." Doctoral thesis, [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973092378.
Full textBiron, von Curland Alexander. "Search for atmospheric muon neutrinos and extraterrestric neutrino point sources in the 1997 AMANDA-B10 data." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964841223.
Full textStröm, Rickard. "Exploring the Universe Using Neutrinos : A Search for Point Sources in the Southern Hemisphere Using the IceCube Neutrino Observatory." Doctoral thesis, Uppsala universitet, Högenergifysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-265522.
Full textIceCube
Conrad, Jan. "A Search for Neutrinos from Cosmic Point Sources using AMANDA-B10 with Emphasis on Limit Calculation Techniques." Doctoral thesis, Uppsala University, Department of Nuclear and Particle Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3591.
Full textA search for cosmic point sources of neutrinos has been performed using data taken in 1999 with the AMANDA-B10 neutrino telescope.
This work describes methods for signal and background separation and the statistical analysis of the final data sample. In particular, the multivariate method Support Vector Machines has been applied to achieve good background rejection while at the same time retaining high signal efficiency.
A grid search covering the complete northern hemisphere revealed no statistical significant excess of events over the expected background from mis-reconstructed cosmic ray induced muons and muons induced by atmospheric neutrinos. Thus, no cosmic point sources of neutrinos have been detected. Upper limits on the neutrino flux for each cell of the grid are presented.
Twenty potential sources of neutrinos chosen among three classes of astronomical objects (Blazars, Super Nova Remnants and Microquasars) have been preselected. Upper Limits on the flux of cosmic neutrinos from those are presented.
The presence of systematic uncertainties makes the calculation of confidence limits an intricate problem. A method is presented which makes it possible to include these uncertainties into the frequentist construction of confidence intervals. Statistical properties of the presented method have been studied.
Lauer, Robert Johannes. "Extending the search for cosmic point sources of neutrinos with IceCube beyond PeV energies and above the horizon." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16177.
Full textSearching for point-like neutrino signals provides a chance of identifying astrophysical particle accelerators as sources of cosmic rays. An established approach to realise high energy neutrino astronomy is the observation of Cherenkov radiation from induced muon tracks in subsurface detectors. Presented here is an analysis based on data taken between 2007 and 2008 with IceCube, the largest of these neutrino telescopes. Neutrino point source searches had been so far restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. This work demonstrates that the region above the horizon can be included by suppressing the background through an energy-sensitive event selection. The approach improves the sensitivity above PeV energies, previously not accessible at all due to absorption of neutrinos from below the horizon. Both celestial hemispheres were scanned to identify neutrino fluxes from individual directions. Based on model predictions for Active Galactic Nuclei, separate tests were performed by compiling a list of specific neutrino source candidates and by searching for short neutrino flares from the blazar 3C279. No significant excesses above the atmospheric background were found. The resulting upper limits on neutrino fluxes are the first that cover point sources in the southern sky up to the EeV energy range. For certain source candidates, these limits provide the best constraints on models predicting neutrinos above PeV energies. Based on the same event sample, a search for correlations between neutrinos and the most energetic charged cosmic rays was performed. The arrival directions of air showers, reported by the HiRes experiment and the Pierre Auger Observatory, were used to determine such coincidences. The result of this study is compatible with the background hypothesis.
Kirn, Malina Aurelia. "Search for Point-Like Sources of Cosmic Rays with Energies Above 10 (18.5) eV in the Hires-I Monocular Dataset." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/kirn/KirnM0505.pdf.
Full textRoensch, Kathrin [Verfasser], and Ulrich [Gutachter] Katz. "Development of a New Reconstruction Algorithm for ANTARES Events and Application to a Search for Neutrino Point Sources / Kathrin Roensch. Gutachter: Ulrich Katz." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2016. http://d-nb.info/1105761266/34.
Full textCarpio, Dumler José Alonso. "Impact of Galactic magnetic field modeling on searches of point sources via ultrahigh energy cosmic ray-neutrino correlations." Master's thesis, Pontificia Universidad Católica del Perú, 2016. http://tesis.pucp.edu.pe/repositorio/handle/123456789/7107.
Full textTesis
Ackermann, Markus. "Searches for signals from cosmic point-like sources of high energy neutrinos in 5 years of AMANDA-II data." Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982713444.
Full textBazo, Alba José Luis Verfasser], Elisa [Akademischer Betreuer] Bernardini, Thomas K. [Akademischer Betreuer] Gaisser, and Hermann [Akademischer Betreuer] [Kolanoski. "Search for steady and flaring astrophysical neutrino point sources with the IceCube detector / José Luis Bazo Alba. Gutachter: Elisa Bernardini ; Thomas K. Gaisser ; Hermann Kolanoski." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://d-nb.info/101497481X/34.
Full textBernhard, Anna [Verfasser], Elisa [Akademischer Betreuer] Resconi, and Lothar [Akademischer Betreuer] Oberauer. "Origin of IceCube's Astrophysical Neutrinos: Autocorrelation, Multi-Point-Source and Time-Structured Searches / Anna Bernhard. Gutachter: Elisa Resconi ; Lothar Oberauer. Betreuer: Elisa Resconi." München : Universitätsbibliothek der TU München, 2015. http://d-nb.info/1067233458/34.
Full textAltmann, Simon David [Verfasser], Alexander [Gutachter] Kappes, ALLAN [Gutachter] HALLGREN, and Thomas [Gutachter] Lohse. "Search for TeV neutrinos from point-like sources in the southern sky using four years of IceCube data / Simon David Altmann ; Gutachter: Alexander Kappes, Allan Hallgren, Thomas Lohse." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://d-nb.info/1127627759/34.
Full textCoenders, Stefan Verfasser], Elisa [Akademischer Betreuer] [Gutachter] Resconi, Jochen [Gutachter] [Greiner, and Miguel [Gutachter] Mostafa. "High-energy cosmic ray accelerators: searches with IceCube neutrinos : Probing seven years of IceCube muon data for time-integrated emission of point-like neutrino sources / Stefan Coenders ; Gutachter: Jochen Greiner, Elisa Resconi, Miguel Mostafa ; Betreuer: Elisa Resconi." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1120013941/34.
Full textAartsen, Mark Gerald. "Improved neutrino point source search method for IceCube's high energy starting event sample." Thesis, 2017. http://hdl.handle.net/2440/115258.
Full textThesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2018
Bäcker, Thomas [Verfasser]. "Weather corrections for a point source search at the Pierre Auger Observatory / vorgelegt von Thomas Bäcker." 2010. http://d-nb.info/1008872741/34.
Full textBraun, James R. "A maximum-likelihood search for neutrino point sources with the AMANDA-II detector /." 2009. http://www.library.wisc.edu/databases/connect/dissertations.html.
Full textHauschildt, Tonio [Verfasser]. "Search for cosmic point sources of high energy neutrinos with the AMANDA-II detector / von Tonio Hauschildt." 2004. http://d-nb.info/973092378/34.
Full textLauer, Robert Johannes [Verfasser]. "Extending the search for cosmic point sources of neutrinos with IceCube beyond PeV energies and above the horizon / von Robert Johannes Lauer." 2010. http://d-nb.info/1010096281/34.
Full textBiron, von Curland Alexander [Verfasser]. "Search for atmospheric muon neutrinos and extraterrestric neutrino point sources in the 1997 AMANDA-B10 data / von Alexander Prinz Biron von Curland." 2002. http://d-nb.info/964841223/34.
Full textAckermann, Markus [Verfasser]. "Searches for signals from cosmic point-like sources of high energy neutrinos in 5 years of AMANDA-II data / von Markus Ackermann." 2006. http://d-nb.info/982713444/34.
Full text