Contributions à la détection directe des ondes gravitationnelles avec Virgo: Caractérisation du détecteur, analyse de données et astrophysique multi-messager
Eric Chassande-Mottin · HAL (Le Centre pour la Communication Scientifique Directe) · 2014
The theory of General Relativity predicts the existence of gravitational waves which are radiative solutions of the Einstein's equations that govern space-time dynamics. Thanks to interferometric detectors such as Virgo, we are probably close to the first direct detection of gravitational waves, that will confirm the indirect evidences collected so far. These detectors allows the observations of gravitational waves from violent cosmic phenomena such as the merger of neutron star and/or black hole binary. In the course of my researches, I contributed, at various levels, to the development and scientific exploitation of these detectors. First, I participated in the instrument starting phase, specifically to the development of a set of pre-analysis tools for the instrumental noise characterization. I also proposed a new method to search for quasi-periodic gravitational signals following an alternative approach to the reference method using matched filtering. The introduction of a Markovian model based on a time-frequency graph allows to reformulate the problem of optimally detecting such signals in a combinatorial optimization problem, for which an efficient search algorithm exists. This new method proves to be particularly useful when the complexity of the targeted signal is large and prohibits the use of matched filtering techniques. Finally, I realized several ``multi-messengers'' search projects that couple gravitational wave observations to that from other channels in the electromagnetic and neutrino spectra.