Observations multi-messagers avec le télescope à neutrinos KM3NeT : recherche de neutrinos de haute énergie en coïncidence avec des transitoires radio rapides

In the era of multi-messenger astrophysics, understanding the most extreme cosmic events of the Universe requires the combined study of several messengers: photons, cosmic rays, gravitational waves and neutrinos. Neutrinos, carriers of the weak interaction, have a crucial role in identifying and characterizing the astrophysical sources that produce them. Among these sources, fast radio bursts (FRBs) are a newly discovered class of intense radio transients of unknown origin. Their observed properties suggest a connection to compact objects, surrounded by dense and magnetized environments favorable to particle acceleration and hence neutrino production.This thesis is part of this search, using data from the KM3NeT neutrino telescope, an underwater infrastructure currently being deployed in the Mediterranean Sea, to search for a correlation between neutrinos and FRBs. Two complementary approaches were taken: a search for close temporal coincidences between the two signals, and a stacked analysis aimed at detecting delayed or persistent neutrino emission from FRB sources. This work is helping to further constrain FRB emission models and assess their role as potential sources of cosmic-ray, while also demonstrating KM3NeT’s growing capabilities in neutrino astronomy.