Dissertations / Theses on the topic 'Coalescence de binaire compacte'

La collaboration LIGO Virgo a marqué les débuts de l'astronomie gravitationnelle en apportant une preuve directe de leur existence en Septembre 2015. Ce domaine connaît depuis un bel essor dont chaque découverte permet une avancée dans les disciplines telles que l'astrophysique, la cosmologie et la physique fondamentale. À l'issue de chaque période d'observation, les détecteurs sont arrêtés et de nombreux aspects sont améliorés. Ce travail s'inscrit durant la phase de préparation entre la période O3 et O4 débutant en mai 2024 visant à configurer les interféromètres dans leurs états avancés en optimisant leurs sensibilités. L'étalonnage devient alors crucial afin de reconstruire avec précision le signal contenant l'information sur les ondes gravitationnelles, permettant les détections et la production de résultats scientifiques comme la mesure de la constante de Hubble, etc. Un travail d'instrumentation a été mené, permettant une mesure précise et régulière de l'horodatage du signal de l'interféromètre, qui doit être maitrisé à mieux que 0.01 ms près dans le but d'une analyse conjointe des données du réseau de détecteurs.De nombreux dispositifs permettant l'étalonnage de l'interféromètre reposent sur la lecture de signaux de contrôles par des photo-détecteurs dont la réponse fréquentielle a été supposée constante. Afin d'éviter tout biais introduit dans la reconstruction du signal, une méthode de mesure se doit d'être développée en vue d'une calibration en fréquence de chaque photo-détecteur impliqué. Deux méthodes sont ici comparées en vue d'une utilisation pour la période O5.Par ailleurs, la sensibilité accrue des détecteurs est synonyme de détections plus nombreuses. Les chaînes d'analyse de la collaboration se doivent de suivre les améliorations instrumentales en développant de nouveaux outils afin d'optimiser la recherche de signal en temps réel. La chaîne d'analyse à faible latence MBTA est un des 4 pipelines d'analyse de la collaboration se concentrant sur la recherche de coalescences de binaires compactes en combinant une analyse indépendante des données des 3 détecteurs. Elle dispose de nombreux outils de réjection de bruit performants, mais ne prend en compte aucune information astrophysique à priori. Grâce à l'accumulation de données dans les périodes d'observation précédentes, la collaboration a pu établir des modèles de distribution de masses plus précis pour les populations de coalescences de binaires compactes. Durant ma thèse un nouvel outil a été développé par l'équipe MBTA en utilisant ces nouvelles informations, visant à estimer la probabilité d'origine des événements (astrophysique ou non) ainsi qu'à en classifier la nature de la source astrophysique. Cet outil a finalement permis de restructurer la chaîne d'analyse globale en l'utilisant comme paramètre principal pour classer les événements selon leur niveau de significativité. La collaboration produit des alertes publiques à faible latences pour l'astronomie multi-messager, dans lesquelles sont fournies des informations liées aux signaux détectés communes aux différents pipelines d'analyses. Ne sachant pas à l'avance les préférences des différentes expériences partenaires de la collaboration LIGO Virgo pour définir les paramètres optimaux permettant un suivi multi-messagers, il a été décidé de tester une autre méthode permettant l'implémentation d'information astrophysique similaires dans la chaîne d'analyse MBTA. Une technique permettant d'inclure l'information astrophysique directement dans le paramètre définissant le classement par niveau de significativité des événements candidats est présentée. Cette méthode permet d'améliorer la recherche en fournissant une meilleure discrimination entre les événements astrophysiques et ceux provenant du bruit d'arrière-plan. En considérant la période d'observation O3 cette méthode permet d'augmenter le nombre de détection de 10% avec MBTA , détections qui ont été confirmés par les autres chaînes d'analyses
The LIGO Virgo collaboration marked the beginnings of gravitational astronomy by providing direct evidence of their existence in September 2015. The detection of gravitationnal wave coming from a binary black holes merger led to the physic's Nobel price. This field has since experienced a great growth, each discovery of which allows an advance in disciplines such as astrophysics, cosmology and fundamental physics. At the end of each observation period, the detectors are stopped and many aspects are improved. This work is part of the preparation phase between period O3 and O4 beginning in May 2024 to configure interferometers in their advanced states in order to optimize their sensitivities. Calibration then becomes crucial in order to accurately reconstruct the signal containing gravitational wave information, allowing detection and the production of scientific results such as the measurement of the Hubble constant, etc. An instrumentation work has been carried out, allowing an accurate and regular measurement of the time stamp (timing) of the readout sensing chain of the interferometer signal, which must be mastered better than 0.01 ms for the purpose of a joint analysis of the detectors network data.Many devices for the calibration of the interferometer rely on the reading of control signals by photodetectors whose frequency response has been assumed to be flat. In order to avoid any bias introduced in the reconstruction of the signal, a measurement method must be developed for a frequency calibration of each photo detector involved. Two methods are compared for use in the O5 period.In addition, the increasing sensitivity of the detectors means more detections. Collaboration analysis chains need to follow instrumental improvements by developing new tools to optimize real-time and off-ligne signal search. The MBTA Low Latency Analysis Chain is one of 4 collaboration analysis pipelines focusing on the search for compact binary coalescences by combining independent data analysis from all 3 detectors. It has many powerful noise rejection tools, but does not take into account any astrophysical information a priori. Through the accumulation of data in previous observation periods, the collaboration was able to establish more accurate mass distribution models for compact binary coalescence populations. During my thesis, a new tool was developed by the MBTA team using this new information, aimed at estimating the probability of origin of events (astrophysics or not) and at classifying the nature of the astrophysical source. This tool finally made it possible to restructure the global analysis chain by using it as the main parameter for classifying events according to their level of significance. The collaboration produces low-latency public alerts for multi-messenger astronomy, providing information related to detected signals common to the different analytical pipelines. Not knowing in advance the preferences of the different experiences partners of the LIGO Virgo collaboration to define the optimal parameters allowing multi-messenger detections, it was decided to test another method to implement similar astrophysical information in the MBTA analysis chain. A technique for including astrophysical information directly in the parameter defining the ranking by significance level of candidate events is presented. This method makes it possible to improve research by providing better discrimination between astrophysical and background noise events. By considering the observation period O3 this method makes it possible to increase the number of detection by 10% with MBTA , detections that have been confirmed by the other chains of analysis

Les campagnes d'observation d'Advanced LIGO/Virgo ont révélé la physique complexe des fusions d'étoiles à neutrons binaires (BNS) et de trous noirs binaires. En 2017, la découverte simultanée des ondes gravitationnelles (OG) et des contreparties électromagnétiques (EM) d'une fusion de BNS a offert une vision détaillée de ce phénomène, avec de nombreux résultats en astrophysique, notamment sur la matière ultra-dense. Cependant, depuis lors, aucune nouvelle détection multi-messagers n'a été réalisée. Cela est dû aux défis des alertes rapides des OG, de la réactivité des télescopes et du traitement des données pour identifier les contreparties EM.L'identification des contreparties EM permet des études scientifiques majeures, comme les contraintes sur l'équation d'état des étoiles à neutrons, la mesure du taux d'expansion de l'univers et la nucléosynthèse des éléments lourds lors d'une kilonova. Pour un suivi rapide, il est essentiel de réduire la zone de localisation du ciel. Les sensibilités variées des détecteurs montrent la complexité du suivi des OG, notamment lors des campagnes LIGO/Virgo/KAGRA (LVK). De nombreux signaux d'OG issus de fusions de binaires compactes sont masqués par le bruit des détecteurs et peuvent être détectés si ce bruit est réduit. Pour maximiser les résultats scientifiques des détecteurs d'OG de LVK, il est crucial de diminuer ce bruit, causé par le bruit environnemental, les artefacts instrumentaux et des bruits plus fondamentaux et irréductibles. L'identification d'événements supplémentaires dépend de notre capacité à réduire ce bruit. Le bruit et la sensibilité influencent directement notre capacité à extraire des informations des signaux d'OG.Pour atténuer ces effets, j'ai développé de nouveaux outils et techniques, tout en améliorant plusieurs anciens. Ces outils d'analyse incluent : i) l'amélioration des capacités du Nuclear Multi-messenger Astronomy (NMMA), une bibliothèque Python pour sonder la physique nucléaire et la cosmologie par une analyse multi-messagers ; ii) la mise à jour et la configuration de télescopes comme le Zwicky Transient Facility (ZTF), le Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) et l'Ultraviolet Transient Astronomy Satellite (ULTRASAT) au sein du Gravitational-wave Electromagnetic Optimization (gwemopt), un outil de simulation de détection de contrepartie EM, à travers un télescope et des informations sur la carte du ciel de l'événement ; iii) l'injection d'une nouvelle distribution, PBD/GWTC-3, dans Ligo.Skymap pour les scénarios d'observation, définissant toutes les populations de coalescence de binaires compacts ; iv) le développement du NMMA-Skyportal, une pipeline intégrant les alertes du ZTF, l'outil Skyportal, une plate-forme collaborative pour l'astronomie temporelle, et NMMA pour discriminer la nature des courbes de lumière en temps réel.De plus, ce travail fournit des projections aux astronomes intéressés par les données produites par les détecteurs d'OG et des contraintes attendues sur le taux d'expansion de l'univers basées sur les données à venir. Ces résultats sont utiles pour ceux qui analysent les données d'OG et recherchent des contreparties EM aux fusions d'étoiles à neutrons. Enfin, pour répondre à la problématique des "signaux astrophysiques noyés" sous le seuil du bruit, j'ai appliqué l'algorithme DeepClean, un réseau de neurones convolutif unidimensionnel, pour estimer, analyser et soustraire les bruits stationnaires et non-stationnaires dans le détecteur Virgo. Une première pour Virgo. En plus de préserver l'intégrité du signal astrophysique, l'algorithme améliore le rapport signal sur bruit du détecteur
The Advanced LIGO/Virgo observation campaigns have revealed the rich and diverse physics of binary neutron star (BNS) and binary black hole mergers. In 2017, the simultaneous discovery of GWs and electromagnetic (EM) counterparts from a BNS merger provided an exceptionally detailed view of this extreme phenomenon, yielding numerous results in both astrophysics and physics, particularly on the behavior of ultra-dense matter. However, despite enormous efforts, no new multi-messenger detections have been made since. This is due to the formidable observational challenge posed by the rapid and precise alerts of GWs, the immediate reactivity of a network of telescopes, and the online data processing required for the identification of EM counterparts.The identification of EM counterparts enables numerous high-priority scientific studies, such as constraints on the equation of state of neutron stars, the measurement of the universe's expansion rate, and the r-process nucleosynthesis of heavy elements produced during a kilonova. For a rapid follow-up of possible counterparts to these events, we must reduce the sky-localization area where the event occurs. However, the significantly different sensitivities of the detectors demonstrate how challenging gravitational-wave (GW) follow-up can be. This is the case for the fourth (ongoing) and fifth LIGO/Virgo/KAGRA (LVK) observation campaigns. Many GW signals from compact binary mergers are hidden by detector noise and can be detected if the noise is sufficiently reduced. To maximize the scientific outcome of the LVK GW detectors, such as the detectability of pre-merger signals, noise must be significantly reduced. Several factors contribute to this noise, undermining the detector's sensitivity, including environmental noise, instrumental artifacts, and some more fundamental and irreducible noises. The identification of additional sub-threshold events is therefore linked to our ability to reduce noise in the instruments. Noise and sensitivity directly influence our capacity to extract information from GW signals.To mitigate these effects, I initially developed new tools and techniques while also making several improvements to existing ones. These analysis tools include, among others, i) enhancing the capabilities of the Nuclear Multi-messenger Astronomy (NMMA), a Python library for probing nuclear physics and cosmology with multi-messenger analysis; ii) updating and configuring telescopes such as the Zwicky Transient Facility (ZTF), the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), and the Ultraviolet Transient Astronomy Satellite (ULTRASAT) within Gravitational-wave Electromagnetic Optimization (gwemopt), a tool for simulating detections using a telescope and event sky map information; iii) injecting a new distribution, PBD/GWTC-3, into Ligo.Skymap for "observing scenarios". This new distribution can define all populations of compact binary coalescences with a single law; iv) developing NMMA-Skyportal, a pipeline that integrates ZTF alerts, the Skyportal tool, a collaborative platform for time-domain astronomy, and NMMA to discriminate the nature of light curves in real-time.Moreover, this work provides projections for astronomers interested in data produced by GW detectors, as well as expected constraints on the universe's expansion rate based on forthcoming data. These results are useful to those analyzing GW data and those seeking EM counterparts to neutron star mergers. Finally, to address the problem of "astrophysical signals bathing" below the noise threshold, I applied the DeepClean algorithm, a one-dimensional convolutional neural network, to estimate, analyze and subtract stationary and non-stationary noises in the Virgo detector. A first for the Virgo detector. In addition to preserving the integrity of the astrophysical signal, the algorithm improves the detector's signal-to-noise ratio

The detection of gravitational waves from the coalescence of two compact objects has been brought to within touching distance by the construction and operation of a global network of laser-interferometer detectors. However, the amplitude of the radiation from these events is so low that direct detection will require the combined innovations of advanced interferometry and detector characterisation, along with powerful methods of extracting weak, but modelled, signals from the background detector noise. This work focuses on enhancing the probability of such detection through improved identi�cation of noise artefacts in the instrumental data, and improved signal processing and extraction. We begin with a recap of the theory of gravitational waves as derived from Einstein's theory of gravity, and the mechanisms that allow propagation of this radiation away from a source. We also catalogue a number of promising astrophysical progenitors, with a focus on compact binary coalescences. We detail the interactions between gravitational waves and an observer, and describe the layout of the large-scale laser interferometers that have been built to enable direct detection. A description of the operation of these detectors during the last science run is given, focusing on their stability and sensitivity, isolating a number of key instrumental noise mechanisms and how they a�ected astrophysical searches over the data. Additionally, we illustrate a new method to improve the identi�cation of seismic noise bursts, allowing their removal from search data, improving search sensitivity. The LIGO and Virgo gravitational-wave detectors operated as a network during the last joint science run. A summary is given of the analysis pipeline used to search for gravitational waves signals from compact binary coalescences using a coincidence-based method, including details of the results of that analysis. Details are also given of the pipeline used to search for gravitational waves associated with short, hard gamma-ray bursts, in which a new coherent method was tuned to search over the reduced parameter space constrained by the electromagnetic counterpart. Finally, we present a new pipeline adapting the coherent method to the blind, all-sky, all-time search, allowing for a more sensitive analysis, as demonstrated by direct comparison.

Le travail présenté est constitué de trois parties indépendantes. Dans la première partie, on étudie à l'aide de la technique SPH (Smoothed Particle Hydrodynamics) la déformation du secondaire au contact de Roche dans les variables cataclysmiques (CV). Ces déformations conduisent à une période orbitable plus grande que celle prévue par la troisième loi de Képler. La prise en compte de cette modification dans des modèles dévolution de CV explique partiellement pourquoi la période des CV observées a un minimum vers 80 minutes. La deuxième partie traite des binaires serrées de naines blanches. On présente un modèle analytique simple du transfert de masse dans ces systèmes lorsque le secondaire remplit son lobe de Roche. L'étude montre que si le rapport des masses est petit (secondaire légerà, alors de transfert de masse est stable et dure typiquement cent millions d'années. Dans le cas contraire, il est instable et la coalescence complète se produit en quelques minutes. Une modélisation SPH montre le déroulement de cette coalescence. La troisième partir concerne le refroidissement des naines blanches isolées pour donner une relation âge-luminosité de ces objets. Le refroidissement est étudié à l'aide d'une code d'évolution stellaire qui calcule complètement la structure de l'étoile (équation d'état, de transfert d'énergie, du mouvement)̀. Ce code est adapté pour traiter la cristallisation du plasma dans le cas d'une composition pure (C ou O) ou d'une mélange (C+O). L'allongement du temps de refroidissement à cause de la cristallisation est étudié. Les courbes de luminosité correspondant à différentes masses sont présentées.

Advanced ground based laser interferometer gravitational wave detectors are due to come online in late 2015 and are expected to make the first direct detections of gravitational waves, with compact binary coalescence widely regarded as one of the most promising sources for detection. In Chapter I I compare two techniques for predicting the uncertainty of sky localization of these sources with full Bayesian inference. I find that timing triangulation alone tends to over-estimate the uncertainty and that average predictions can be brought to better agreement by the inclusion of phase consistency information in timing-triangulation techniques. Gravitational wave signals will provide a testing ground for the strong field dynamics of GR. Bayesian data analysis pipelines are being developed to test GR in this new regime, as presented in Chapter 3 Appendix B. In Chapter II and Appendix C I compare the predicted from of the Bayes factor, presented by Cornish et al. and Vallisneri, with full Bayesian inference. I find that the approximate scheme predicts exact results with good accuracy above fitting factors of ~ 0.9. The expected rate of detection of Compact Binary Coalescence signals has large associated uncertainties due to unknown merger rates. The tool presented in Chapter III provides a way to estimate the expected rate of specified CBC systems in a selected detector.

L'ère de l'astronomie gravitationnelle a commencé avec la première détection d'une onde gravitationnelle le 14 septembre 2015, par la collaboration LIGO-Virgo. Les premières détections proviennent de coalescences de trous noirs de quelques dizaines de masses solaires. Le détecteur européen Advanced Virgo a redémarré en 2017 pour participer aux prochaines détections d'ondes gravitationnelles et localiser les sources astrophysiques.Cette thèse a pour sujet les différentes étapes du processus de détection des ondes gravitationnelles : de l'étalonnage du détecteur Advanced Virgo à l'analyse en temps réel des données du réseau d'interféromètres LIGO-Virgo. Dans un premier temps, les objectifs, la méthode et les résultats de l'étalonnage du détecteur Advanced Virgo sont décrits. Cette étape est cruciale pour comprendre la sensibilité du détecteur et pour reconstruire l'amplitude de l'onde gravitationnelle. Un nouvel algorithme, SilenteC, développé pendant la thèse est ensuite détaillé : son objectif est d'identifier les sources de bruits non-stationnaires qui limitent la sensibilité des analyses. Certains bruits transitoires interviennent de façon non-linéaire et SilenteC tente de repérer ce type de contribution. Enfin, l'analyse MBTA à faible latence pour la recherche des signaux d'ondes gravitationnelles issus de coalescences de binaires compactes est décrite. En particulier, l'accent est mis sur la caractérisation de vétos permettant de distinguer les signaux astrophysiques à sélectionner et les bruits transitoires à rejeter le plus efficacement possible
The era of gravitational astronomy began with the first detection of a gravitational wave on September 14, 2015, by the LIGO-Virgo collaboration. The first detections come from coalescences of black holes with masses of a few tens of solar masses. The European detector Advanced Virgo restarted in 2017 to participate in the next detections of gravitational waves and to locate the astrophysical sources.This thesis deals with the different stages of the gravitational waves detection process: from the calibration of the Advanced Virgo detector to low-latency analysis of the LIGO-Virgo interferometer network data. First, the objectives, method and results of the detector calibration are described. This step is crucial for understanding the sensitivity of the detector and for reconstructing the amplitude of the gravitational wave. A new algorithm, SilenteC, developed during the thesis is then detailed: its objective is to identify the sources of non-stationary noises that limit the sensitivity of the analysis. Some transient noises are non-linear and SilenteC tries to identify this type of contribution. Finally, low-latency MBTA analysis for the detection of gravitational wave signals from compact binary coalescences is described. In particular, emphasis is put on the study of vetos making it possible to distinguish the astrophysical signals to be selected and the transient noises to be rejected as efficiently as possible

Many gravitational wave sources will produce electromagnetic signals as they emit gravitational waves. An important example is binary neutron star mergers. The joint observations and discoveries of the electromagnetic signatures of these gravitational wave sources can produce substantial scientific benefits in physics, astrophysics and cosmology. To maximize the scientific outcomes of such gravitational events as much as possible, the detections of their electromagnetic signatures are necessary. The first detection of the inspiral signals from binary neutron stars by LIGO and VIRGO, and the observations of the associated electromagnetic counterparts throughout the electromagnetic spectrum have served an excellent example. These detections and discoveries have also ushered in a new era of both gravitational wave astronomy and multi-messenger astronomy. However, using gravitational wave interferometric detectors, the sky location estimates of the gravitational wave signals from binary neutron star can span a few hundreds square degrees, unless there are three or more detectors observing the event simultaneously. The large sky localization error poses a challenge for astronomers scanning the localization error to look for the electromagnetic signals of these gravitational wave events. The electromagnetic counterparts may also not be readily detectable depending on the distance and orientation of the sources, which presents further difficulties in detecting their signals. To alleviate the situation, we develop an algorithm to maximize the detection probability of the electromagnetic counterparts of gravitational wave events. The algorithm we develop is able to generate an observing strategy that optimizes the probability of successful electromagnetic follow-up observations given limited observational resources. This is achieved by using a greedy algorithm for tiling the sky location error and Lagrange multiplier for assigning observation times to observation fields. The analysis with the algorithm also allows an estimate of the detection probability. In Chapter 3, we present a proof-of-concept demonstration of this algorithm to four telescopes Subaru-HyperSuprimeCam, CTIO-Dark Energy Camera, Palomar Transient Factory and Pan-Starrs, for three different simulated binary neutron star events, assuming kilonova to be the target electromagnetic counterpart. By applying the algorithm to telescopes with arbitrary field of view and sensitivity within a range, we provide an insight into the potential of future telescopes and other telescopes not directly included in our analysis. Moreover, the algorithm is applied to the design of a space based mission, the Einstein Probe, to find the optimal combination of the size of field of view and the sensitivity. The localization of gravitational wave sources, which is determined both by the gravitational wave signals and the detectors, is an important factor to the success of electromagnetic follow-up observations. We investigate the localization of binary neutron star mergers detected with the Einstein Telescope and Cosmic Explorer. Compared to the existing detectors, the improvement in the sensitivity of the Einstein Telescope and Cosmic Explorer in the low frequency band has many important implications. One of them is the considerable increase in the length of the in-band of the signals from binary neutron stars, which is useful in localizing the sources. In Chapter 4, using a Fisher matrix approach, we estimate the sky localization error of binary neutron stars as a population and distributed at various distances. As the extended in-band duration of signals also increases the possibility of identifying and releasing the presence of a signal prior to merger, known as early warning, we investigate the prospect for early warning of binary neutron star merger events with these detectors. While the Einstein Telescope and Cosmic Explorer hold promising future for gravitational wave astronomy, they are not likely to be operative until the 2030s. In the literature, detectors designed with more advanced technologies than LIGO and VIRGO are proposed to fill the gap in time. We estimate the localization of binary black holes with two such detectors in Australia and China and seconds generation detectors such as LIGO, LIGO India, VIRGO and KAGRA. In chapter 5, we study electromagnetic observations of binary neutron star mergers with the Large Synoptic Survey Telescope. The Large Synoptic Survey Telescope is a telescope designed with large size of field of view and excellent sensitivity in its observing bands. Such a telescope provides a promising prospect for multimessenger astronomy with gravitational waves. With its sensitivity and field of view, the telescope is expected to enable electromagnetic follow-up observations with shorter exposure time and fewer observation fields than many existing telescopes. We define a simple procedure for electromagnetic follow-up observations triggered by gravitational waves using the telescope. Taking advantages of the Fisher matrix approach in Chapter 4 for the sky location estimates, we quantify the observation time necessary for the telescope to perform electromagnetic follow-up observation of binary neutron star mergers detected with different networks of gravitational wave detectors.

This thesis concerns the use, in gravitational wave data analysis, of higher order wave form models of the gravitational radiation emitted by compact binary coalescences. We begin with an introductory chapter that includes an overview of the theory of general relativity, gravitational radiation and ground-based interferometric gravitational wave detectors. We then discuss, in Chapter 2, the gravitational waves emitted by compact binary coalescences, with an explanation of higher order waveforms and how they differ from leading order waveforms we also introduce the post-Newtonian formalism. In Chapter 3 the method and results of a gravitational wave search for low mass compact binary coalescences using a subset of LIGO's 5th science run data are presented and in the subsequent chapter we examine how one could use higher order waveforms in such analyses. We follow the development of a new search algorithm that incorporates higher order waveforms with promising results for detection efficiency and parameter estimation. In Chapter 5, a new method of windowing time-domain waveforms that offers benefit to gravitational wave searches is presented. The final chapter covers the development of a game designed as an outreach project to raise public awareness and understanding of the search for gravitational waves.

Cette thèse de doctorat présente une enquête approfondie sur la détection des signaux d'ondes gravitationnelles provenant de fusions binaires compactes, en mettant l'accent particulier sur l'analyse des données de la troisième campagne d'observation de la Collaboration LIGO-Virgo. Le manuscrit commence par fournir une introduction aux principes fondamentaux de la théorie de la relativité générale, y compris la prédiction de l'existence des ondes gravitationnelles et un aperçu des sources astrophysiques qui génèrent ces ondes. Il fournit également une description détaillée des interféromètres, les instruments utilisés dans les observatoires d'ondes gravitationnelles, ainsi que leur fonctionnement de base. Ensuite, le manuscrit se concentre sur les techniques avancées d'analyse des données développées pour extraire les signaux d'ondes gravitationnelles du bruit du détecteur. Une attention particulière est accordée au pipeline d'analyse MBTA (Multi-Band Template Analysis), auquel l'auteur contribue activement en tant que membre de l'équipe MBTA. Le fonctionnement et la méthodologie du pipeline MBTA sont décrits en détail, mettant en évidence son rôle dans la détection et l'analyse des signaux d'ondes gravitationnelles. Ensuite, le manuscrit présente les résultats obtenus à partir de l'analyse standard réalisée pour rechercher des signaux provenant de trous noirs binaires, d'étoiles à neutrons binaires et de binaires trou noir-étoile à neutrons dans les données recueillies lors de la troisième campagne d'observation. L'analyse comprend un examen approfondi des signaux observés, de leurs propriétés et des implications astrophysiques des fusions détectées. De plus, le manuscrit explore les dernières avancées dans la recherche des ondes gravitationnelles émises par des binaires de masse sub-solaire, qui impliquent des systèmes binaires comprenant au moins un objet ayant une masse inférieure à celle du Soleil, offrant une enquête approfondie sur la méthodologie et les résultats de la recherche de masse sub-solaire lors de la troisième campagne d'observation. Grâce à cette enquête approfondie, le manuscrit vise à contribuer à l'avancement de l'astronomie des ondes gravitationnelles, offrant une exploration complète de la recherche sur les ondes gravitationnelles, couvrant les principales réalisations de la troisième campagne d'observation dans les recherches standard et de masse sub-solaire
This PhD thesis presents a comprehensive investigation into the detection of gravitational wave signals from compact binary mergers, with a specific focus on the analysis of data from the third observing run of the LIGO-Virgo Collaboration. The manuscript begins by providing an introduction to the fundamental principles of the theory of General Relativity, including the prediction of the existence of gravitational waves and an overview of the astrophysical sources that generate these waves. It also provides a detailed description of interferometers, the instruments used in gravitational wave observatories, and their basic functioning. Subsequently, the manuscript focuses on advanced data analysis techniques developed to extract gravitational wave signals from the detector noise. Special attention is given to the Multi-Band Template Analysis (MBTA) pipeline, which the author actively contributes to as part of the MBTA team. The functioning and methodology of the MBTA pipeline are described in detail, highlighting its role in the detection and analysis of gravitational wave signals. The manuscript then proceeds to present the results obtained from the standard analysis conducted to search for signals originating from the coalescence of binary black holes, binary neutron stars, and black hole-neutron star binaries in the data collected during the third observing run. The analysis includes a comprehensive examination of the observed signals, their properties, and the astrophysical implications of the detected mergers. Additionally, the manuscript explores the latest advancements in the search for gravitational waves emitted by sub-solar mass binaries, which involve binary systems comprising at east one object with a mass below the threshold of the mass of the Sun, providing an in-depth investigation into the methodology and results of the sub-solar mass search during the third observing run. Through this comprehensive investigation, the manuscript aims at contributing to the advancement of gravitational wave astronomy, offering a comprehensive exploration of gravitational wave research, encompassing the main achievement of the third observing run in both standard and sub-solar mass searches

Advanced LIGO's first observing run marked the birth of gravitational-wave astronomy through the first detection of gravitational waves from coalescing black holes-GW150914. Advanced LIGO's second and Advanced Virgo's first observing run marked the birth of multimessenger astronomy with first joint observations of gravitational and electromagnetic radiation associated with coalescing neutron stars-GW170817. The electromagnetic observations included detection of a burst of gamma rays produced by the merger, and a kilonova powered by the radioactive decay of r-process nuclei synthesized in the neutron star coalescence ejecta. Gravitational waves from compact binary coalescences carry fingerprints of the sources that generated them. Studying them allows us to test Einstein’s general relativity in the strongest regimes, where it has never been tested before, and study matter at densities beyond reach of the most powerful laboratories on our planet. Moreover, we can gain insight about the evolution of stars, galaxies and even the Universe as a whole by studying the merger rate of compact objects. Joint electromagnetic and gravitational-wave observations help develop our understanding of the physical processes that occur in such systems, and provide a new method of probing cosmological parameters.

GW170817 was detected by the GstLAL pipeline in low-latency making the extensive electromagnetic followup possible. The GstLAL pipeline is a matched filtering pipeline that uses compact binary coalescence waveform models to filter the data from gravitational-wave detectors in the time-domain. It can detect gravitational waves from coalescing compact binaries in near real time and provide point estimates for binary parameters. This thesis describes the methods, developments, and the results from the GstLAL pipeline over the course of the first two observing runs of Advanced LIGO, focusing on the contributions made by the author. We also present a study about the prospects of observing a cosmological stochastic background which is expected to be buried under the astrophysical background from the population of coalesceing compact binaries with third-generation gravitational-wave detectors.

Compact binary coalescing systems: binary neutron stars, neutron star black hole pairs and binary black hole systems, represent promising candidates for gravitational wave first detection and have the potential to provide precise tests of the strong-field predictions of general relativity. Observations of binary black hole (BBH) systems will provide a wealth of information relevant to fundamental physics, astrophysics and cosmology. The search for such systems is a major priority of the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations. A major area of research within LIGO-Virgo analysis groups is incorporation of spin into the search template banks used for binary black hole systems. In this dissertation, I compare the injection efficiency and parameter recovery from three binary black hole searches. One of the searches presented here uses non-spinning templates and represents the standard LIGO search for binary black holes with total masses between 35 and 100M[circle with dot]. The other two use spin aligned and anti-aligned templates representing a future search for black hole binary systems with total masses between 35-100M[circle with dot]. One of the two spinning searches has the spin parameter set to zero, nonspinning, as a check of the spinning method. (Additionally the (anti-)aligned spin searches use a retooling of the standard pipeline taking advantage of a code base designed specifically to handle Advanced LIGO data.) All three searches were run on artificial data created by the Numerical Injection Analysis 2 collaboration (NINJA2) containing Gaussian noise and numerically generated signals modeling aligned and anti-aligned spinning binary black holes. I found that for the analyzed two weeks of data the three searches recover injections with nearly equal efficiency; however, the spinning search recovers the parameters of the injections more accurately than the non-spinning search. Specifically, the parameter recovery of the spins shows a correlation between the injected and recovered spins, and the addition of spin to the template bank improves the recovery of the signal-to-noise ratio and the chirp mass for an injected signal. While spin aligned situations are geometrically low probability configurations, there are plausible astrophysical effects that lead to alignment of spins prior to merger. Therefore my results show that the spin-aligned template bank search represents an improvement on the standard non-spinning search in the highmass region and should be pursued on real data.
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In this thesis, we probe several aspects of compact binary environments, focusing on results of orbits and collisions of compact objects. First, we describe a search for low-mass compact-binary-coalescence gravitational-wave signals in data from the LIGO detectors' most sensitive, longest-running science run to date (S5). We also go into detail on the interpretation of the results including its development. We then investigate the bounds on the mass of the graviton that could be achieved from the detection gravitational waves from a binary black hole merger. Last, we study the flow of momentum in compact binaries using the Landau-Lifshitz formalism.