Gravitational-wave astronomy with compact binary coalescences : from blip glitches to the black hole area increase law

Abstract

The beginning of gravitational-wave astronomy dates from the 14th of September 2015, when the Laser Interferometer Gravitational-wave Observatories (LIGO) measured a gravitational wave for the first time. This signal originated from a pair of merging black holes, providing direct confirmation of the existence of binary systems formed by two black holes. To date, a total of five confirmed and one candidate gravitational-wave signals from binary black holes have been announced. Furthermore, a gravitational-wave signal from a neutron star binary has been observed jointly with electromagnetic radiation. These observations entail a breakthrough in the astronomy of compact binaries and provide insight into highly relativistic systems. In this work we cover several areas from the gravitational-wave astronomy of compact binary coalescences. We begin by introducing data analysis techniques used during the second generation of ground-based gravitational-wave observatories. Using real results from astrophysical signals, we explain the procedures to estimate the statistical significance of gravitational-wave signals. We observe a specific type of short noise transients in the data, commonly known as blip glitches, that is particularly harmful for transient gravitational-wave searches. Here we introduce a method to identify occurrences of blip glitches. With the results obtained, we investigate the origin of these noise transients and present here the current state of these investigations. Astrophysical gravitational-wave signals allow for tests of general relativity that would otherwise not be possible. For instance, the ringdown phase of a compact binary coalescence is characteristic of the nature of a Kerr black hole. With Bayesian inference and using only this ringdown signature, we develop a method to estimate the parameters of the remnant black hole after a binary coalescence. This method lays the foundations to perform tests of the no-hair theorem and of the black hole area increase law. In this work we focus on the latter, for which we also need to use the inspiral signature of the coalescence. We devise a well-defined condition for the end of the inspiral stage by combining information from post-Newtonian theory with the exact Kerr test-mass limit. Our result is called the hybrid MECO (Minimum Energy Circular Orbit). We develop a method to test the area increase law in which this hybrid MECO is used to separate the inspiral part of the signal and measure the initial parameters of the binary. Comparing the inspiral measurements with the ringdown parameters on a simulated signal, we find that the area theorem could be confirmed to ~74.6% confidence with current sensitivity. This result can improve to ~99.9% confidence using future design sensitivities.