Potential PhD projects: Gravitational Wave Astrophysics

Gravitational Wave Astronomy

Supervisor: Dr Christopher J. Moore (Email cmoore[at]star.sr.bham.ac.uk)

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.

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 at the end of 2022 and are expected to observe hundreds of binary systems of black holes and neutron stars over the next few years. The project will focus on characterising the physical properties of the individual 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.

Tackling the global analysis challenge of the Laser Interferometer Space Antenna

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

ESA's Laser Interferometer Space Antenna (LISA) is going to be the first gravitational-wave observatory opening the mHz observational window onto the universe. LISA will discover tens of thousands of compact objects, from sub-solar mass white dwarfs in our galaxy to massive black holes at the centre of galaxies throughout the Universe. Projects are available to develop data analysis capabilities to maximise the science exploitation of this unique mission, using a combination of machine learning/AI techniques and (hierarchical) Bayesian inference tools.

Project title: Characterising the optical counterparts to gravitational waves

Supervisor: Dr Matt Nicholl (Email: mnicholl[at]star.sr.bham.ac.uk)

Joint detections of gravitational and electromagnetic radiation from the same source offers a new way to study the Universe. Mergers of double neutron star binaries lead to ‘kilonovae’: a week-long glow powered by the radioactive decays from heavy nuclei forged in the explosion. This was confirmed in spectacular fashion by the first optical emission found from a gravitational wave source, GW170817. It produced a mass many times that of the Earth in gold alone, suggesting that such mergers may be the dominant production site of most heavy elements in the Universe.

The goal now is to increase our understanding of neutron star and kilonova physics by detecting and characterising more sources. As gravitational wave detectors become more sensitive over the coming years, the rate of discoveries for neutron star mergers will increase from one to 10s or more per year. The student will develop machine learning and Big Data tools to discover kilonovae and other rare events from optical observations. During LIGO’s fourth observing run, they can join the ENGRAVE collaboration to follow-up gravitational wave triggers and hunt for kilonovae with the Very Large Telescope.

An indication of the type of work to be carried out can be found here (my paper on the GW170817 kilonova): https://arxiv.org/pdf/1710.05456.pdf