Dr Lionel London (Cardiff University)
Slightly perturbed dissipative systems display characteristic solutions that are not quite normal modes. Nevertheless, these quasi-normal modes encode valuable information about the underlying physics, as well as the nature of the preceding perturbation. In the case of black holes, this means that quasinormal modes may tell us not only about the source spacetime, but also about that...
Dr Carlos Filipe Da Silva Costa (INPE)
In General Relativity, the Quasi Normal Modes (QNM) from a perturbed Kerr Black Hole (BH) are the superimposition of damped sinusoids. These modes are completely defined by the final black hole parameters, mass and spin. For the current generation of the ground based detectors, the gravitational waves associated with the QNM are weak and hence the extraction of single QNMs is...
Dr Collin Capano (Albert Einstein Institute)
The distribution of the component spins of binary black holes is one of the most astrophysically interesting results that could be produced by gravitational-wave detectors in the coming years. Unfortunately, the component spins are also one of the most difficult parameters to infer from gravitational waves. Better measurements are obtained of the “effective spin” and "effective precession"...
Dr Chandra Kant Mishra (IIT Madras)
Compact objects such as neutron stars or black holes or those of more exotic origin, by the virtue of their spin incur deformations that can be characterised in terms of the spin-induced quadrupole and other higher order moments. The magnitude of these deformations depends on the specific nature of compact objects in question. If the compact object is a Kerr black hole, its quadrupole moment...
Dr Sebastian Khan (AEI Hannover)
The interpretation of gravitational waves from coalescing compact binaries relies on accurate source models which are used in complex data analysis techniques. State-of-the-art models used in LIGO analyses make a number of assumptions that may severely limit their accuracy for systems with, e.g., asymmetric masses or large misaligned spin magnitudes that cause precession. In this talk I...
36. A new method for incorporating precession and higher-order modes in searches for compact binaries
Dr Joshua Willis (Abilene Christian University)
Advanced LIGO's current matched-filter searches for binary mergers model only the dominant mode of binaries whose orbital angular momentum is aligned with the total angular momentum. Some models of binary formation predict a population of systems where these simplifying assumptions will not hold, and so a search that includes them may be necessary to discriminate between these models. In this...
50. How do black hole binaries form ? Studying stellar evolution with gravitational wave observations
Dr Irina Dvorkin (Institut d'Astrophysique de Paris)
The recent detection of gravitational waves by Advanced LIGO demonstrates the existence of binary black holes that merge within the age of the Universe. Moreover, the first LIGO event originated from the merger of black holes more massive than previously observed in X-ray binaries in our Galaxy. Future observations with LIGO and VIRGO will probe the mass and spin distributions of black holes...
Dr Felix Mirabel (CEA-France & CONICET-Argentina)
I will present the current theoretical models and the multiple strands of observational evidence for the formation of binary stellar black holes, the first sources of gravitational waves detected by LIGO. It is believed that stellar black holes (BHs) can be formed in two different ways: Either a massive star collapses directly into a BH without a supernova (SN) explosion, or an explosion...
Dr Letizia Sammut (Monash University)
Following the first Advanced LIGO detection, several studies investigated the possibility that GW150914 was of primordial origin and could provide evidence that stellar-mass black holes form part of dark matter. The support for the primordial hypothesis is extremely circumstantial. However, these studies raise an interesting question: how can one confirm or refute the primordial hypothesis for...
Dr Chunglee Kim (Korea Astronomy and Space Science Institute (KASI))
The first GW source that is confirmed by the advanced LIGO is a binary black hole (BBH). In coming years, advanced LIGO and advanced Virgo will find more BBHs. In this work, we investigate dynamically formed BBHs in core-collapsed globular clusters using direct N-body simulations. We assume two types of BH mass functions: two-component mass function and a continuous mass function (adapted from...
Dr Chad Hanna (Penn State)
The first direct detection of gravitational waves originated from a binary black hole coalescence during advanced LIGO's first observing run in September 2015. A subsequent confirmed detection in December of the same year established the birth of gravitational wave astronomy and the expectation that binary black hole mergers will be frequently observed with ground-based gravitational...
Dr Christopher Berry (University of Birmingham)
Gravitational-wave observations allow us to infer black hole spins. We will review spin measurements from current LIGO observations of binary black holes. The orientations of the spins are a tracer of the formation mechanism. While spin measurements from individual systems have large uncertainties, more information can be gained by combining the population of results. We show how a...
Mlle Miriam Cabero Mueller (Albert Einstein Institute Hannover)
Observations of gravitational waves from binary black hole coalescences provide an opportunity for testing the black hole area increase law, also known as the area theorem. For loud enough signals, the inspiral (ringdown) part of the waveform provides a measurement of the initial (final) parameters of the black holes. We explore how to perform such measurements with Advanced LIGO in order...
Prof. Tjonnie Li (The Chinese University of Hong Kong)
Gravitational lensing phenomena are widespread in electromagnetic astrophysics, and in principle may also be uncovered with gravitational waves. We examine gravitational wave events in the limit of geometric optics, where we expect to see multiple signals from the same event with different arrival times and amplitudes, and wave optics, where we expect to see effects such as interference and...