En esta tesis se tratan diferentes aspectos de la acústica presente en un telescopio submarino de neutrinos, principalmente en dos vertientes: en el sistema de posicionamiento acústico utilizado para la monitorización de las posiciones de los módulos ópticos presentes a lo largo del detector, así como en sistemas para detección acústica de neutrinos, técnica que actualmente está en fase de estudio. Todos los estudios realizados están enmarcados dentro de dos colaboraciones europeas para el diseño, construcción y operación de telescopios submarinos de neutrinos: Antares (en fase de operación) y KM3NET (en fase de diseño). Objetivos. Los objetivos de este trabajo pueden resumirse en los siguientes aspectos: - Estudios y análisis del sistema de posicionamiento acústico de Antares. Desarrollo del software para la para la automatización del procesado de los datos de dicho sistema e incorporación de los resultados en la base de datos del experimento. Análisis de los datos proporcionados por dicho sistema con el fin de validar su correcto funcionamiento. - Diseño y desarrollo del sistema de posicionamiento acústico para KM3NeT, telescopio unas 20 veces más grande que Antares. - Estudios para la evaluación de la generación acústica paramétrica para el desarrollo de un calibrador compacto capaz de generar señales tipo neutrino útiles en sistemas de detección acústica. Elementos de la metodología a destacar. Cabe destacar aquí que el trabajo se ha desarrollado en el marco de dos colaboraciones internacionales: ANTARES y KM3NeT, financiados con fondos europeos y nacionales. Por su contexto y el carácter de las actividades realizadas ha sido necesaria la formación en distintos campos: telescopios de neutrinos y astropartículas, pero también en otras áreas como la acústica submarina. Además, se ha desarrollado diversas capacidades y destrezas en diversos ámbitos: en instrumentación, en aplicaciones informáticas, en análisis de datos, etc. Más concretamente, se ha trabajado en aplicaciones informáticas para los desarrollos y análisis en ANTARES. / Bou Cabo, M. (2011). Acoustics for underwater neutrino telescopes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10989 / Palancia

Astrophysical events that evolve on short timescales (from milliseconds to years) are widely referred as transient events. In many cases, transient events are explosions or mergers of astrophysical objects that emit particles of all energies. This thesis focuses on very-high-energy (VHE; 100 GeV to 100 TeV) gamma rays, observed by the VERITAS telescope, to understand two types of transients, superluminous supernovae (SLSNe) and classical novae. In the first part, the background physics and technical approach of an imaging atmospheric Cherenkov technique deployed by VERITAS is reviewed in depth, including the analysis pipeline of VERITAS data, from camera data reduction to high level analysis output. In addition to supporting the ongoing work at VERITAS, the second part of this thesis describes the extensive effort to develop, commission and align the optical system of the prototype Schwarzschild-Couder telescope, also located at the VERITAS observatory. This new telescope provides an wider field of view and higher angular resolution compared with the conventional IACT design of current telescopes, and will join the next generation of VHE telescopes in the Cherenkov Telescope Array (CTA) project currently in development. The observation and analysis of two SLSNe is performed, on SN 2015bn and SN 2017egm, with both VERITAS and Fermi-LAT telescopes. The upper limit is reported on both events and is compared to a simple and a self-consistent model for parameter estimation. In addition, a population of sources were analyzed to estimate the future detection potential of new SLSNe with several gamma-ray observatories. Finally, the observation and analysis of several novae were performed. These sources were observed with VERITAS and Fermi-LAT. The observation of Nova Herculis 2021 is noteworthy in that the overlap of both observations may constrain the cutoff energy of the nova spectral model, providing a estimate for the maximum energy of the accelerated particles in the nova’s shock region.

No description available.

Une des priorités scientifiques justifiant la construction de télescopes géants (classe 30-50m) est l'étude des premières générations de galaxies situées à de très grands décalages vers le rouge (1

A subaperture configuration to test aspheric optical components or systems is developed. The method developed has potential for testing rotationally symmetric aspheres without the use of null lenses. The aperture is divided into annular subaperture regions and an interferometer is refocused for each region to reduce the fringe density. Essential mathematical treatments involving annular subapertures, such as annular Zernike polynomials, are provided in detail. Numerical and experimental validations of the algorithm are described. Tolerance analyses on subaperture measurements are given. Computer programs were written to link the subaperture Zernike coefficients and to determine the full-aperture Zernike coefficients.

The LSST M1/M3 combines an 8.4 m primary mirror and a 5.1 m tertiary mirror on one glass substrate. The combined mirror was completed at the Richard F. Caris Mirror Lab at the University of Arizona in October 2014. Interferometric measurements show that both mirrors have surface accuracy better than 20 nm rms over their clear apertures, in near-simultaneous tests, and that both mirrors meet their stringent structure function specifications. Acceptance tests showed that the radii of curvature, conic constants, and alignment of the 2 optical axes are within the specified tolerances. The mirror figures are obtained by combining the lab measurements with a model of the telescope's active optics system that uses the 156 support actuators to bend the glass substrate. This correction affects both mirror surfaces simultaneously. We showed that both mirrors have excellent figures and meet their specifications with a single bending of the substrate and correction forces that are well within the allowed magnitude. The interferometers do not resolve some small surface features with high slope errors. We used a new instrument based on deflectometry to measure many of these features with sub-millimeter spatial resolution, and nanometer accuracy for small features, over 12.5 cm apertures. Mirror Lab and LSST staff created synthetic models of both mirrors by combining the interferometric maps and the small high-resolution maps, and used these to show the impact of the small features on images is acceptably small.

Approved for public release; distribution is unlimited / Design Center of the Naval Postgraduate School. The objective of this simulator is to provide on-the-ground simulation of the dynamics and control of spacecraft for high precision Acquisition, Tracking and Pointing applications associated with space based laser relay. The required initial attitude determination accuracy for the Bifocal Relay Mirror test-bed is 10 æ-radians. Normally, in laboratories where very high initial attitude knowledge is required, actual (space qualified) star trackers are incorporated into the testbed design. This is not possible at NPS as the laboratory does not have a skylight to allow visual access to the stars, and the photosensitive nature of many of the experiments would make such an opening inconvenient. Since it is critical to the operation of the testbed to provide accurate attitude knowledge, a substitute system was required. The present thesis documents the development of a new attitude sensor capable of providing attitude information within the required 10æ-radians (within a field of view of the order of 1 deg). The concepts leading up to the final design, the testing and selection of the equipment used in the final configuration, and a detailed explanation of how the final system calibration was performed are discussed in detail. / Lieutenant, United States Navy

Dark matter particles in the form of supersymmetric Weakly Interacting Massive Particles (WIMPs) could accumulate in the centre of the Sun because of gravitational trapping. Pair-wise annihilations of WIMPs could create standard model particles out of which neutrinos could reach the Earth. Data from the IceCube 22-string neutrino telescope have been searched for signals from dark matter annihilations in the Sun. Highly sophisticated analysis methods have been developed to discern signal neutrinos from the severe background of atmospheric particle showers. No signal has been found in a dataset of 104 days livetime taken in 2007, and an upper limit has been placed on the muon flux in the South Pole ice induced by neutrinos from the Sun, reaching down to 330 km-2y-1. The flux limit has been converted into an upper limit on the neutralino scattering cross-section, which reaches down to 2.8*10-40 cm2 for spin-dependent interactions. / Four articles are appended to the thesis:I. G. Wikström for the IceCube collaboration, Proc. of the 30th ICRC,arXiv/0711.0353 [astro-ph] (2007) 135.II. A. Gross, C. Ha, C. Rott, M. Tluczykont, E. Resconi, T. DeYoung and G. Wikström for the IceCube Collaboration, Proc. of the 30th ICRC,arXiv/0711.0353 [astro-ph] (2007) 11.III. G. Wikström and J. Edsjö, JCAP 04 (2009) 009.IV. R. Abbasi et al. (IceCube collaboration), accepted for publication in Phys. Rev. Lett., arXiv/0902.2460v3 [astro-ph.CO] (2009). / IceCube

The cubic-kilometer sized IceCube neutrino observatory, constructed in the glacial ice at the South Pole, searches indirectly for dark matter via neutrinos from dark matter self-annihilations. It has a high discovery potential through striking signatures. This thesis presents searches for dark matter annihilations in the center of the Sun using experimental data collected with IceCube. The main physics analysis described here was performed for dark matter in the form of weakly interacting massive particles (WIMPs) with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore sub-array was included in the analysis, lowering the energy threshold and extending the search to the austral summer. Data from 317 days live-time are consistent with the expected background from atmospheric muons and neutrinos. Upper limits were set on the dark matter annihilation rate, with conversions to limits on the WIMP-proton scattering cross section, which initiates the WIMP capture process in the Sun.These are the most stringent spin-dependent WIMP-proton cross-sections limits to date above 35 GeV for most WIMP models. In addition, a formalism for quickly and directly comparing event-level IceCube data with arbitrary annihilation spectra in detailed model scans, considering not only total event counts but also event directions and energy estimators, is presented. Two analyses were made that show an application of this formalism to both model exclusion and parameter estimation in models of supersymmetry. An analysis was also conducted that extended for the first time indirect dark matter searches with neutrinos using IceCube data, to an alternative dark matter candidate, Kaluza-Klein particles, arising from theories with extra space-time dimensions. The methods developed for the solar dark matter search were applied to look for neutrino emission during a flare of the Crab Nebula in 2010.

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