The last decade has seen an explosion of exoplanet detections. We now know most stars host a planetary system; however, these exoplanetary systems are incredibly diverse and unlike our Solar-System. Using the ALMA telescope, we have been able to image the planet-forming environments (protoplanetary discs) at unprecedented resolution and sensitivity. These images have revealed that these protoplanetary discs are being shaped and disrupted by planets forming within them.  However, linking the properties of planet-forming discs to the observed exoplanet population remains an unsolved theoretical problem. This project involves building theoretical models of how forming planets will interact with their parent protoplanetary discs and linking them to current observations. This project will allow the student to undertake sophisticated hydrodynamical computer simulations of planet formation and/or become involved in state-of-the-art observations

The Euclid satellite, scheduled for launch in late 2023, will survey one-third of the sky, producing catalogues with billions of detected sources. A few hundred of these will be quasars in the early Universe, seen as they were less than a billion years after the Big Bang, and a few will be beyond the current record of redshift z = 7.5. This project is to develop methods to undertake this rare object search and then apply them to the Euclid data as it becomes available. As such, it sits at the interface between astronomy, statistics and data science, so it would suit a student interested in these areas.

The cosmic microwave background (CMB) has proven to be the richest source of information about the cosmological model. Most of that information is encoded in the angular power spectra of fluctuations in temperature and polarisation, which are in turn directly determined by the cosmological parameters. However, the cosmological power spectra are inevitably contaminated by astrophysical and instrumental systematics and sources of noise. This project will address the dominant noise source of CMB detectors, by using novel techniques of likelihood-free inference to eliminate the dependence of measurements of the spectra on the so-called autocorrelation noise in a principled, Bayesian setting. This work will develop and test the techniques on medium-scale problems such as data from the ~50 detectors on the Planck satellite and eventually scale up to applications with the tens of thousands of detectors on forthcoming projects such as the Simons Observatory, expected to start taking data in 2023-4.

With the launch of the James Webb Space Telescope, we are studying the atmospheres of exoplanets in exquisite detail. The data quality far exceeds our ability to model and understand atmospheres theoretically. In this project, motivated by new observations, you will explore previously neglected atmospheric processes and combine them into a new theory for exoplanet atmospheres. This project can focus on a single or multiple aspects depending on the student's interests. The project will involve a balance of computational and theoretical methods, with the balance to be determined by the student. The student may have the opportunity to get involved in modelling and interpreting new, state-of-the-art observations, as well as the planning of future observations. 

White Dwarfs are one of the end stages of stellar evolution, and most stars will end their lives as white dwarfs. Significantly, all planet-hosting stars will evolve into white dwarfs eventually. Many white dwarfs are "polluted" in that their atmospheres show evidence of the remnants of planetary material ripped apart by the white dwarf's immense gravity. This planetary material is believed to make it onto the white dwarf through an accretion disc. However, current theoretical models of these discs fail to explain the observations. In this project, you will build a new theory for accretion discs around polluted white dwarfs, using techniques developed for accretion discs around young stars and black holes. You will have the opportunity to test your theory against new data from the DESI survey, which will run concurrently with this project. 

M dwarfs are small, cool stars that comprise 80% of the stellar population. We now know that most of these stars harbour Earth to super-Earth sized planets, and that a significant fraction of these planets lie in the Habitable Zone. This has the remarkable implication that there are billions of potentially habitable planets in our galaxy. However, whether or not a planet in the Habitable Zone is actually habitable depends critically on its atmospheric properties. These properties in turn depend on the chemical species outgassed from the planetary interior, as well as on the subsequent evolution of these gases under the influence of stellar irradiation and various chemical and dynamical interactions. In this project we will combine existing models for planetary interiors (that predict which species are outgassed) with atmospheric evolution models to study the production and evolution of various possible planetary atmospheres in the Habitable Zone of M dwarfs. The goals of the project are: (1) to identify broad classes of atmospheres that may arise on these planets; (2) to identify observational signatures of these classes; and (3) determine the atmospheric conditions consistent with habitability. The project will require a combination of numerical simulations and theory, as well as interfacing with state-of-the-art observations of planetary atmospheres by facilities such are JWST and ARIEL.

One of the last frontiers of astrophysics is the first billion years of the Universe, when the formation of the first galaxies and black holes produced the first star light leading to a Cosmic Dawn. Observations of the 21 cm line of neutral hydrogen in the radio promises to open a window onto this period (z=6-27) for the first time. Interferometers like LOFAR, HERA, and SKA will map fluctuations in the 21cm signal, while single dipole experiments like EDGES and REACH hope to detect the all sky global signal. These new experiments are expected to provide new insights into astrophysics and cosmology and are already starting to provide interesting data. The student will be part of a collaboration preparing for SKA observations and thinking about the analysis of REACH to develop new statistical and modelling techniques for 21cm experiments.

• Exoplanets origins and evolution - Dr James Owen
• The most luminous galaxies in the local Universe - Dr Dave Clements
• Astropysics and cosmology from the 21cm line - Dr Jonathan Pritchard
• Cosmology with the next generation of CMB experiments - Prof Andrew Jaffe
• Planet formation and habitability - Dr Subu Mohanty
• The first quasars and supermassive Black Holes - Dr Daniel Mortlock
• Bayesian Analysis of the dynamic Universe - Dr Florent Leclercq and Prof Alan Heavens
• Bayesian analysis of weak gravitational lensing - Prof Alan Heavens and Prof Andrew Jaffe
• Searching for the most distant quasars - Dr Daniel Mortlock
• Higgs, Dark Matter and the Global Search for Physics beyond the Standard Model - Dr Pat Scott
• Direct Detection of Dark Matter and Global Fits - Prof Roberto Trotta
• Cosmology and Fundamental Physics with Euclid - Prof Roberto Trotta
• Extreme Dusty Star-Forming Galaxies - Dr Dave Clements
• The Nature and Evolution of 70 micron selected galaxies - Dr Dave Clements
• The X-ray-Starburst Connection in the Herschel Era - Dr Dave Clements
• Advanced statistical methods for astrophysical probes of dark energy - Prof Roberto Trotta
• The early Universe and cosmological parameters from the Cosmic Microwave Background, Gravitational Waves, and other observations - Professor Andrew Jaffe
• Determining the topology of the Universe from the Cosmic Microwave Background - Professor Andrew Jaffe
• Accretion Disks, Planet Formation and Habitability Around Red and Brown Dwarfs - Dr Subu Mohanty
• Towards optimal statistics of reionization a5 Emulating radiation from variable stars - Dr Yvonne Unruh nd the 21 cm signal - Dr Jonathan Pritchard
• Cool pre-main sequence stars: their surfaces and circumstellar environments - Dr Yvonne Unruh
• Understanding solar brightness changes on climate-relevant time scales - Dr Yvonne Unruh
• Gravitational lensing, dark matter, and black holes - Professor Steve Warren
•  The most luminous galaxies in the local Universe - Dr Dave Clements
• Pushing the limits of high-z LSS structure cosmology - Dr Boris Leistedt
•  Emulating radiation from variable stars - Dr Yvonne Unruh
• Cosmology with likelihood-free inference - Prof Alan Heavens
•  The highest redshift quasars - Professor Stephen Warren
• Planet Formation in the Inner Disc-The First End to End Model - Dr Subu Mohanty
• Stellar Brightness Variability and Exoplanets – Dr Yvonne Unruh
• The Earliest Stages of Planet Formation - Dr Richard Booth
• Molecules in the Atmosphere of Venus - Dr David Clements and Dr Ingo Mueller