Ultra-high-energy neutrino search with the Pierre Auger Observatory in the era of Gravitational Wave astronomy

Abstract

This thesis is focused on the search of Ultra High Energy (UHE) neutrinos with energies above 10^17 eV with the Pierre Auger Observatory. The thesis has several parts. On the one hand in Chapter 2, the procedure used to search for inclined showers and neutrinos within the Observatory data is detailed and its effectivity is studied using simulated showers induced by neutrinos. The procedure is applied to the data between 1st January 2004 and 31st August 2018 revealing no neutrino candidates. In Chapter 3 the detector exposure for diffuse sources and the effective area for point-like sources of UHE neutrinos are characterized for the main neutrino channels in terms of neutrino flavors and interactions, source position, time and duration of the neutrino flux. Improved limits both for diffuse and for point like sources are obtained. Chapter 4 deals with the follow up in UHE neutrinos of events detected in gravitational waves with the LIGO and Virgo interferometers that is, the search of coincident neutrino events and the study of the implications of the resulting absence of candidates. Finally, a summary with the main conclusions and results obtained in the thesis is also provided.