Méthode de détection de sources individuelles d'ondes gravitationnelles par chronométrie d'un réseau de pulsars : application aux données de l'EPTA

摘要

The existence of gravitational waves, ripples in space-time itself, has been predicted but their detection remains elusive. Multiple techniques exist for searching for them, including ground-based kilometer long inteferometers. In this thesis, we present an alternative approach, based on the monitoring and precise timing of radio pulses from an array of millisecond pulsars. A gravitational wave will perturb the propagation of those radio pulses, causing them to reach the Earth with a certain delay. By searching for correlations in the arrival times of the pulsations from different pulsars, we can in principle infer the presence of gravitational waves from observations. We begin by giving an overview of pulsar observations and timing. We illustrate those principles with a practical example : the study of the millisecond pulsar J1614-2230. In the second part we describe gravitational waves, the sources that create them, and the various detection methods. Then, we focus on the pulsar timing array technique, and its potential application to the search for gravitational waves from supermassive black hole binary system. We pursue with a detailed description of the statistical and numerical tools that we used in the present work, and present the results of a search ofr an injected signal in the real EPTA data set. Finally, we employ our new method to derive upper limits on the amplitude of a putative signal in the same EPTA data set, as a function of the frequency and sky location of the supermassive black hole binary system.