Potential PhD projects: Gravitational Wave Astrophysics

Entering the large-statistics regime of gravitational-wave astronomy

Supervisor: Dr Davide Gerosa (Email dgerosa[at]star.sr.bham.ac.uk)

The first observations of gravitational waves by LIGO and Virgo have ushered us into the golden age of gravitational-wave discoveries. Hundreds, if not thousands, of new events are expected to be observed in the next few years as detectors reach their design sensitivities. Such large catalogs of gravitational-wave observations will open new, unprecedented opportunities in terms of both fundamental physics and astrophysics. Crucially, they will need to be faced with increasingly accurate theoretical predictions.

First, among large catalogs, there will be "golden" events. We expect systems that, because of their properties, are particularly interesting to carry out som e specific measurements (perhaps because of their favorable orientations, or because they are very massive, or very rapidly rotating, etc). Second, large catalo gs need to be exploited with powerful statistical techniques. New tools and techniques need to be developed (and immediately applied!) to maximize the scientific payoff of current and future gravitational-wave observatories.

To get a feeling about the kind of research you will be doing, here are a couple of papers by Dr. Gerosa relevant to this project:

For more information, please see Dr Gerosa's webpage at https://davidegerosa.com

Gravitational waves from binary and triple star systems

Supervisor: Dr Silvia Toonen (Email toonen[at]star.sr.bham.ac.uk)

The first detection of gravitational waves in 2015 opened up a completely new way of studying our Universe and the stars within them. From a handful of gravi tational wave bursts detected so far, we will go to hundreds of detections over the next few years. The bursts are linked to mergers between black holes and neu tron stars, and directly provide information on their properties,about the evo lution up to the merger remains highly debated. The aim of this project is to ex plore the evolution self-consistently using stellar evolution modelling and popu lation synthesis. With a computational approach, the student will study not only binary evolution, but also focus on the cutting-edge field of triple evolution using innovative methods and codes. The student will identify the stellar merger s, compute their occurrence rate for various assumptions of stellar evolution an d interaction, and finally map the expected masses and rates onto results from g ravitational wave detectors such as LIGO, and in the future LISA.

Review paper on the evolution of triple star systems and its modelling http://adsabs.harvard.edu/abs/2016ComAC...3....6T

Gravitational Wave Astronomy

Supervisor: Dr Christopher J. Moore (Email christopher.moore[at]tecnico.ulisboa.pt)

The era of gravitational wave astronomy has begun. LIGO and Virgo have unearthed the signals from several pairs of merging black holes and one pair of merging neutron stars. Many more events are expected over the next few years. These signals must be compared against detailed theoretical models to enable us to accurately determine the properties of the sources. These theoretical models will need to be significantly improved to cope with the exquisite, high signal to noise ratio , observations promised by the next generation of ground-based detectors, as well as the upcoming space-based detector, LISA. This new generation of gravitational wave instruments will pose new challenges that must be overcome in order to maximise their scientific potential. These challenges include, for example, managing very long duration signals containing many more wave cycles, avoiding confusion when analysing data sets containing multiple simultaneous overlapping signals, and efficiently combining the information from the large numbers of events to learn about the underlying astrophysical processes. This project will aim to tackle some of these future challenges whilst also working with the current LIGO and Virgo observational data.

Gravitational Waves from Binary Black Holes

Supervisor: Dr Patricia Schmidt (Email: P.Schmidt[at]astro.ru.nl)

Gravitational waves from merging black holes are a powerful tool to probe the fundamental nature of black holes and study their properties. Current measurements only allow us to place weak constraints on the mass ratio and the black hole spins. Improvements to gravitational-wave detectors will increase their sensitivity and thus also allow for more accurate measurements in the future. This require s accurate models of the gravitational-wave signal. The goal of this project is to improve the waveform models for binary black holes and to understand the consequences for Bayesian parameter estimation and tests of General Relativity in Advanced LIGO and beyond. This project will use tools and techniques from analytical relativity and provide the student with opportunity to perform targeted numerical relativity simulations of binary black hole mergers in order to further our understanding of the highly nonlinear merger of two coalescing black holes. Additionally, the successful candidate will also have opportunities to actively participate in the analysis of LIGO data.

To successfully complete this project, strong mathematical skills are required. Programming experience in Python and/or C is advantageous. Applicants must have had an introduction to General Relativity.

Studying the physics and populations of black holes and neutron stars wi th gravitational-wave observations

Supervisor: Prof Alberto Vecchio (Email: av[at]star.sr.bham.ac.uk)

Projects are available to use LIGO/Virgo data to characterise the properties of black holes and neutron stars in binary systems, and the behaviour of extreme space-times. The gravitational-wave instruments LIGO and Virgo will re-start observations at improve sensitivity in early 2019 and are expected to observe about a hundred of binary black holes and a handful of binary neutron stars in the period 2019-2022. They could also discover the first neutron star-black hole system. The project(s) will focus on characterising the physical properties of the indi vidual systems and, from those, the properties of the underlying populations. For selected systems, it may also be possible to use the gravitational-wave data to test specific predictions of general relativity.