# Potential PhD projects: Gravitational Wave Astrophysics

- Physics and astrophysics of black hole collisions: Dr Gregorio Carullo
- Gamma-ray bursts and multi-messenger astronomy: Dr Ben Gompertz
- Compact Binaries: Dr Geraint Pratten
- Gravitational Waves from Neutron Star Binaries: Dr Patricia Schmidt
- Studying the physics and populations of black holes and neutron stars with gravitational-wave observations: Prof Alberto Vecchio
- Tackling the global analysis challenge of the Laser Interferometer Space Antenna: Prof Alberto Vecchio

# Physics and astrophysics of black hole collisions

Supervisor: Dr Gregorio Carullo (Email g.carullo[at]bham.ac.uk) Coalescences of two black holes are the most powerful cosmic events happening throughout the Universe. Their dynamics sources the strongest gravitational fields experimentally accessible, and gives rise to violent space-time deformations known as gravitational waves. The observation of gravitational waves by the large scale LIGO-Virgo interferometers on Earth has opened a golden era of strong-gravity exploration, powering the largest surge ever witnessed in gravity-related research worldwide. Despite rapid progress, many open questions still remain, as our understanding of the general-relativistic two-body problem is far from complete. The PhD candidate will delve into strong-gravity research, and gain experience into both advanced modelling methods in General Relativity and cutting-edge statistical inference techniques deployed on large supercomputers, applied to gravitational wave signals detected by current earth-based observatories or upcoming space-based missions. Details of the project will be agreed with the candidate depending on their interests and inclinations, but specific examples of challenging problems on which the aforementioned skills could be used include: measuring yet unobserved black holes vibrational spectra, modelling the near-merger two-body dynamics, developing innovative inference techniques targeting highly eccentric binaries, or probing the nature of black hole event horizons. |

# Project: Gamma-ray bursts and multi-messenger astronomy

Supervisor: Dr Ben Gompertz Gamma-ray bursts are the most powerful explosive events in the universe, releasing as much energy in 10 seconds as the entire Milky Way galaxy does in several years. They are associated with either the collapse of very massive stars (long gamma-ray bursts) or collisions between two neutron stars or a neutron star and a black hole (short gamma-ray bursts). Because of this, gamma-ray bursts can tell us about some of the most extreme environments in nature, and are confirmed counterparts to gravitational-wave sources. During this PhD, students will have the opportunity to research the systems that produce gamma-ray bursts, the environments they explode into, their connection to the creation of the heaviest elements in the universe, and their ability to probe gravitational-wave sources. An interested student will be able to join international collaborations like GOTO, LSST, STARGATE, and ENGRAVE, and gain access to some of the most powerful telescopes and satellite observatories in the world. For more information, please email Dr. Ben Gompertz (bgompertz[at]star.sr.bham.ac.uk) |

# Compact Binaries

Supervisor: Dr Geraint Pratten (Email gpratten[at]star.sr.bham.ac.uk) Compact binaries, consisting of pairs of black holes or neutron stars, are extremely powerful sources of gravitational radiation. Vital information on the physics that drives the coalescence of these binaries is directly encoded in the gravitational-wave signal. By decoding this information, we can obtain crucial knowledge on the origin and evolution of astrophysical black holes and neutron stars throughout the Universe. Our ability to extract this information requires developing new and increasingly sophisticated theoretical models for the gravitational-wave signal. This PhD project will aim to tackle key questions in gravitational-wave astronomy and fundamental physics. Research topics include: the analytical modelling of gravitational dynamics and radiation, numerical relativity simulations of compact binaries, acceleration techniques for gravitational-wave data analysis, testing fundamental physics in the strong-field regime, modelling neutron star mergers, and exploring our understanding of the neutron star equation of state. The PhD Student will be strongly encouraged to join the LIGO Scientific Collaboration and be given the opportunity to work directly with gravitational-wave data and to play a role in the gravitational-wave discoveries made by the LIGO detector |

# Gravitational Waves from Neutron Star Binaries

Supervisor:Supervisor: Dr Patricia Schmidt (Email: P.Schmidt[at]@bham.ac.uk) Gravitational waves from colliding neutron stars provide a unique opportunity for probing the properties of ultra-dense matter and fundamental interactions in extreme regimes. This PhD project focuses on modelling tidal effects in the waveforms emitted by binary neutron stars, and subsequently applying these models to parameter estimation and population inference, with an emphasis on determining the as-of-yet unknown neutron star equation of state (EOS). The successful candidate will work to create cutting-edge models using post-Newtonian (PN) and numerical relativity techniques to better capture the complex physics of neutron star systems. They will then apply these models within a Bayesian inference framework to analyse gravitational-wave data, enabling new insights into the structure of neutron stars and EOS properties. This project offers a unique opportunity to innovate in waveform modelling and conduct novel analyses of gravitational-wave observations. They will also be encouraged to join the LIGO Scientific Collaboration. Ideal applicants will have a strong background in theoretical astrophysics and general relativity, computational and analytical skills as well as core statistics knowledge. |

# 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 have re-started observations at improved sensitivity in mid 2023 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.