Search for cosmic sources in neutrino telescopes and time calibration in the antares neutrino telescope
- Autores: Javier Barrios Martí
- Directores de la Tesis: Juan Zúñiga Román (dir. tes.), Juan de Dios Zornoza Gómez (codir. tes.)
- Lectura: En la Universitat de València ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Chad Finley (presid.), Sergio Palomares Ruiz (secret.), Dorothea Franziska Elisabeth Samtleben (voc.)
- Programa de doctorado: Programa de Doctorado en Física por la Universitat de València (Estudi General)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TESEO
- Resumen
High energy neutrino astronomy is currently at an early yet intriguing stage. The first results observed by the IceCube Collaboration have shown the existence of a high energy neutrino flux of unknown origin with apparently no privileged direction. The ANTARES neutrino telescope has been able to exclude the possibility that some of these IceCube events events had been produced due to a point-source at the Galactic Centre region. Furthermore, the last diffuse-flux ANTARES analysis has shown a result which is compatible with the flux observed by IceCube.
Currently, there are three high-energy neutrino telescopes in operation: ANTARES, IceCube and Baikal. Furthermore, the KM3NeT Collaboration is building the largest neutrino telescope network ever built. The analyses explained in this Thesis mostly deal with data taken from ANTARES and IceCube, although prospects of the future KM3NeT are also given.
Two have been the main goals of the work presented. The first one has been to improve the current time calibration of the ANTARES neutrino telescope so to have the highest quality data possible. The second one has been to improve our knowledge about the existence of point and extended cosmic neutrino sources. No significant observations of these type of sources have been found in the analysis presented. Furthermore, an estimation of the sensitivity of particular point and extended source searches in the future KM3NeT telescope has been carried out.
A 1 ns accuracy level in the time measurements is needed in order to be able to reconstruct events with a median angular resolution of 0.3 degrees for neutrino energies above 10 TeV. A new time calibration procedure has been performed for most of the data taking period of the ANTARES telescope. This calibration has been performed by using events coming from K40 disintegrations for the so-called intra-storey calibration (time offset determination between ARSs in the same storey), and by taking the information of the time residuals obtained after the reconstruction of down-going atmospheric muon events in the inter-line (time offsets between lines) and inter-storey (between storeys) calibrations. This new calibration procedure has shown to increase the number of well-reconstructed down going events, which indicates an improvement of the reconstruction.
The results of three different searches of point and extended neutrino sources have been presented. The first one corresponds to the first combined analysis between ANTARES and IceCube, which used ANTARES data taken between 2007 and 2012, and IceCube data from the 40-, 59- and 79-strings configurations (2008 to 2011). Only track events coming from the Southern Sky were considered. This analysis has proven the complementarity of both detectors for these type of searches in the Southern Sky. IceCube presents a better sensitivity for high energy neutrinos due to its larger size, but a worse sensitivity for events with energies under 100 TeV because of the declination-dependent energy cut used to suppress the background of atmospheric muons. The second one is the point and extended source search using ANTARES data between 2007 and 2015, which corresponds to the first published analysis that includes shower events in this type of analysis in ANTARES, allowing an all neutrino flavour search. A better angular resolution in shower-like events is observed in ANTARES compared to Ice- Cube, leading to a value between 2 and 3 degrees for the former. Even if the angular resolution for showers is worse compared to track-like events, an improvement of approximately 20% on the sensitivity is achieved with the addition of these events. No significant clusters have been observed in these searches. The last one corresponds to the performance estimation of the future KM3NeT telescope for these type of searches by using only the cascade channel, in which a detailed study for two candidate galactic neutrino sources, SNR RXJ 1713,7-3946 and PWN Vela X is also performed.
