PhD studentships

Find out more about our available projects and what to expect from our Astronomy PhD.

Projects and supervisors

We offer around 10 PhD projects each year, spanning the breadth of our research in astronomy and cosmology. STFC funding is typically available for two to three students annually. 

We also encourage you to discuss your own ideas for research projects with potential supervisors. You can find recent papers by our staff using NASA/SAO ADS or the preprint arXiv (astro-ph). You can discuss projects in more detail before giving final preferences.

Admissions 2026

• What to expect from the PhD

  Our PhD programme typically takes three to four years and is primarily research-based. Alongside your research project, you will attend a range of short courses designed to develop essential research skills and provide an overview of current topics in astrophysics.

  Projects span the full breadth of our research activities and may be theoretical, observational, or a combination of both. During your PhD, you will have opportunities to present your work at international conferences and engage with the wider research community. Students working on observational projects often undertake observing trips to major telescope facilities around the world.

  You will be assigned a supervisor and an initial research project when you join the Centre, although there is flexibility to refine your research direction as your interests develop. A second supervisor provides additional expertise and support throughout your studies.

  Your progress is reviewed annually through written reports and interviews, ensuring you receive the guidance and support needed to complete your PhD successfully.

  We typically welcome four to five new PhD students each year, with STFC-funded studentships usually available for two to three students.

• How to apply

  Please make application through the University's on-line admissions system. We review applications on a rolling basis throughout the year, but if you wish to be considered for STFC funding you should apply by the end of January. 

  You do not need to prepare a research proposal. Although the application form asks for one, we instead ask that you list the PhD projects and/or supervisors that interest you most.

   

• STFC funded studentships

  Students from around the world are welcome to apply for our STFC-funded PhD studentships. These studentships cover tuition fees at the UK home rate, provide an annual maintenance stipend, and include additional funding to support research training and travel.

  To be considered for STFC funding, you should submit your application by the end of January. We may continue to consider applications after this date until all positions have been filled. Interviews are typically held in late February or early March.

• Requirements

  Read our course requirements.

  Our PhD programme is primarily research-focused, with limited taught content in core astrophysics. Applicants are therefore expected to have a strong background in physics and astronomy before beginning their studies.

  If your first degree is in a related discipline – such as electrical or aerospace engineering, computer science, or mathematics – you will usually need additional postgraduate training with a substantial physics or astrophysics component before applying.

  Many students from these backgrounds choose to complete one of our MSc programmes in Astronomy or Cosmology before progressing to a PhD at Sussex or at other leading institutions worldwide.

• If your academic training is not in astrophysics

  Because the PhD focuses almost entirely on research, there is limited opportunity to gain core astrophysics knowledge during the programme.

  If your first degree is in another discipline, such as electrical or aerospace engineering, computing or pure mathematics, you’ll usually need a Masters with a substantial physics or astrophysics component before applying.

  Many students from these backgrounds complete our MSc courses in Astronomy or Cosmology before applying to study for a PhD at Sussex or elsewhere.

Projects 2026

These projects are available for 2026 admission. We typically add new projects and update existing ones early each calendar year for the following admissions cycle.

• Non-Gaussianity from inflation: Chris Byrnes
  

  It is well known that multi field inflation can lead to large non-Gaussianity of the so called local type, however it is less well appreciated that in “many” cases multifield inflation does not lead to any observable deviation from single-field inflation. Non-Gaussianity is usually parametrised using the amplitude fNL and until now only values of fNL>>1 would be observable. However, galaxy surveys in the next decade promise to be able to probe the interesting regime of fNL~1 (provided systematics can be kept under control), which is arguably the value which should expected in several classes of multi field inflation such as the curvaton scenario or modulated reheating. 

   The broad goal of this PhD project would be to better understand which classes of models predict fNL~1, to what extent the prediction can be mode more accurate than an order of magnitude, and how “natural” these theories are compared to those which predict fNL<<1. Both analytical and numerical skills would be important. 

   For a review about primordial non-Gaussianity see https://arxiv.org/abs/1508.06740. Relevant reading of papers by the proposed supervisor include https://inspirehep.net/literature/1643257 and https://inspirehep.net/literature/1286295 and https://inspirehep.net/literature/790119. 

• Linking fundamental physics to cosmological data with the large-scale structure of our Universe: Eva-Maria Mueller*
  

  Our Universe still holds many mysteries, from its earliest beginnings to its current accelerated expansion driven by dark energy. While studying the origin and evolution of our Universe is exciting by itself, we can also use our Universe as the largest laboratory we have to push our understanding of the laws of physics!

  Today, one of the riches cosmological probes is the large-scale structure of our Universe. Galaxies are not equally distributed across the sky but cluster in particular patterns tracing the underlying density field. The Dark Energy Spectroscopic Instrument (DESI) is a new wide-field spectrograph at the Mayall telescope. DESI has started its 5-year survey mapping the 3D positions of tens of millions of galaxies across almost half the sky and has already produced the largest 3D map of our Universe. DESI will obtain order-of-magnitude improved measurements of the Universe’s accelerated expansion, leading to a revolutionary understanding of dark energy. The aim of this project is to make use of this new era of galaxy survey data to test the standard cosmological model and to look for new fundamental physics by analysing the large-scale structure in the distribution of galaxies.

  This PhD project ranges from developing new analytical and statistical methods to constraining fundamental physics. You can set the emphasis on either the theoretical understanding of the underlying cosmological model or the hands-on data analysis side (or anything in between).

  For more information/to apply for this project, please contact Eva-Maria Mueller

• Simulating the Cosmological Structures: Ilian Iliev*
  

  The small density inhomogeneities left over from the period of fast initial expansion of the universe gradually grew under the force of gravity, and eventually formed the galaxies and large-scale structures which we see today. Within this project we will be using the results from large, state-of-the-art numerical N-body simulations on supercomputers aimed  at understanding this process. In particular, we will study the non-linear evolution of structures - clustering, sub-structures and internal properties of galactic and cluster dark matter halos, redshift-space distortions and others. We will be comparing these features to data from large galaxy surveys in order to derive the fundamental parameter describing the universe we live in.

• Signatures of Cosmic Reionization: Ilian Iliev*
  

  After the hot Big Bang the Universe expanded and cooled, eventually turning the primordial soup of particles into a sea of neutral gas, thereby starting the cosmic 'Dark Ages'. The light produced by the First Stars during the subsequent 'Cosmic Dawn' gradually ionized the universe again and ended the Dark Ages. This transition, called Cosmic Reionization had profound effects on the formation and character of the early cosmological structures and left deep impressions on subsequent galaxy and star formation.

  Within this project you will be running and analysing the results from state-of-the-art, massively-parallel simulations of this process, on some of world's largest computers, with the aim to infer the observable features produced by these first structures. These results will be used for interpreting the data from the LOFAR observatory and making predictions for Square Kilometre Array (SKA). Our group is closely involved with both of these Epoch of Reionization experiments and we are leading the numerical simulation work for them. You will be part of these international collaborations and will have the opportunity to visit our international collaborators for both short and extended time periods to work on joint projects.

• Microwave Background polarization and lensing: Antony Lewis*
  

  The cosmic microwave background (CMB) originates from a time when the universe was only a few hundred thousand years old, a distance 98% of the way to the edge of the observable universe. The Planck satellite has observed the fluctuations in the CMB with unprecedented precision, and now a new wave of observations are measuring the polarization with ever better precision. The polarization gives a powerful way to constrain early-universe physics (via the so-called "B-modes" from gravity waves from the early universe, on much larger scales than the waves recently detected by Ligo). B-mode polarization also gives a measure the gravitational lensing of the CMB, leading to a projected map of all the matter in the universe between us and the big bang, a probe of neutrino mass and dark energy. Sussex is a member of the Simons Observatory LiteBird and CMB-S4. We also have world-leading theoretical expertise, developing several of the key codes that are used to make the cosmological predictions. There's exciting opportunity to join a team working on developing analysis tools, theoretical predictions and data analysis tools for Simons Observatory (and possibly LiteBird) over the time of the PhD. The project(s) would include some analytic work, as well as extensive numerical calculations and simulations.

  For more information/to apply for this project, please contact Antony Lewis.

• Galaxy surveys with 4MOST, Euclid and LSST: Jon Loveday*
  

  This project will ensure that we are well-prepared to fully exploit data from upcoming galaxy surveys, in particular the 4-metre Multi-Object Spectrograph (4MOST) Cosmology and WAVES surveys, but also imaging data from Euclid and LSST.  These surveys will revolutionise our understanding of galaxy evolution and cosmology.  Studying the small-scale clustering and dynamics of galaxies, typically in group environments, will be used to constrain the nature of dark matter.

   Specific sub-projects include, but are not limited to:

  1. Group identification.  Various methods have been proposed for identifying groups of galaxies in spectroscopic surveys, such as friends-of-friends, halo-based, and probabilistic methods.  Using current survey and simulated data, you will explore the pros and cons of the various methods in order to identify an optimum group catalogue in 4MOST survey data.

  2. 4MOST selection functions.  Not every target galaxy will have a successfully measured redshift: some will be missed due to observing constraints, others will be observed, but may lack features that allow redshift determination.  Keeping track of survey completeness will be vital for accurate determination of galaxy clustering.  You will use realistic simulations to test proposed methods for tracking survey completeness.

  3. Use of marked correlation functions to distinguish cosmological models.  Weighting, or 'marking' each galaxy by a measure of its environment generalises the clustering of void galaxies at one extreme, and clusters at the other.  You will use state of the art simulations to optimise weighting schemes to gain maximum cosmological information.

  4. Low surface-brightness galaxies.  Current determinations of the abundance of dwarf galaxies are almost certainly underestimates due to incompleteness in low-surface brightness galaxies in extant imaging surveys such as SDSS.  Euclid and LSST will enable detection of galaxies of much lower surface brightness than hitherto possible over large areas of sky, allowing accurate estimates of the abundance of these faint objects.  This in turn will provide important constraints on the nature of dark matter.

   Funding: STFC quota studentship or other

   For more information/to apply for this project, please contact Prof. Jon Loveday.
  

• Co-Evolution of Galaxies and Supermassive Black Holes Since Cosmic Noon with PRIMA: Seb Oliver
  

  Star formation and black hole growth are perhaps the two most intriguing aspects of galaxy evolution. While galaxies and their central black holes operate on vastly different spatial scales, the Universe today shows a remarkable scaling relationship between galaxy stellar mass and central black hole mass. How did this come to be? Did they grow together, or via episodes where one is dominant and the other suppressed?

  The Probe far-infrared Mission for Astrophysics, PRIMA, will provide the first integrated census of star formation and black hole growth when galaxy evolution was most active, between ~ 9 billion and 3 billion years ago. PRIMA's far-IR spectrophotometry simultaneously measures black hole accretion rate, star formation rate, and outflows from massive star-forming galaxies to establish how they are linked.

  This simultaneous measurement is only possible in the mid- and far-infrared because dust obscures UV and optical radiation which is often used to track star formation, and gas obscures X-rays typically used to track black hole growth.

  PRIMA is being proposed as the first $1B NASA Astrophysics Probe-class mission. It would be launched in 2032. Prof. Seb Oliver is one of the 27 PRIMA co-investigators and leads the UK involvement in PRIMA, funded by the UK Space Agency. Critical to PRIMA’s success will be to employ the world-leading XID+ modelling methodology developed here at the University of Sussex in Oliver’s group to disentangle the emission from different galaxies.

  Your project will be to develop the XID+ modelling. The hyperspectral imaging and spectroscopy of PRIMA provide the keys to unlocking blended emission from multiple galaxies. You will extend XID+ to fully exploit this new information. You will test your methods on state-of-the-art galaxy evolution simulations. You will design the experiments that can be done with PRIMA and how they will be able to answer these fundamental questions.

  For more information/to apply for these projects, please contact Prof. Seb Oliver.

• Clusters of galaxies as cosmological probes and astrophysical laboratories: making use of the latest X-ray and optical surveys: Kathy Romer
  

  Delivering Cosmological Precision through the Application of X-ray Cluster EXpertise: CosmoXCX

  Supervisors: Dr Kathy Romer and Dr Paul Giles  (in collaboration with these international consortia XMM Cluster Survey, Euclid, and the LSST Dark Energy Science Collaboration (LSST:DESC))

   After twenty-five years, Dark Energy is still a mystery. The late time acceleration of the expansion of the Universe remains one of the biggest unsolved puzzles in physics today. Clusters of galaxies play a vital role in Dark Energy experiments because they probe not only the geometry of the Universe but also probe the growth of structure. The field is set to take a major leap forward thanks to two new galaxy surveys that cover large areas of sky to unprecedented sensitivity: Euclid (from space) and LSST (from Chile). However, even with the superb cluster catalogues that Euclid and LSST will deliver, it will not be possible to derive cosmological constraints without additional information at other wavelengths: complimentary X-ray observations are essential. Kathy Romer, is recruiting two PhD students to work on the project titled Delivering Cosmological Precision through the Application of X-ray Cluster eXpertise} (CosmoXCX). Student 1 (who could be STFC funded) would construct and analyse sub-samples of clusters with X-ray observations. They will be responsible for the calibration of the Mass Observable Relation critical for the derivation of dark energy parameters from Euclid and LSST clusters. This is an observational, plus data analysis, project. Student 2 (who would be self funded) would be responsible for extracting cosmological parameters from cluster catalogues calibrated using X-ray observations. This is a theory, plus data interpretation, project. 

  For more information please read PhD projects with Kathy Romer.

• Back reaction and renormalization in cosmological correlation function: David Seery*
  

  Measurement and inference in cosmology generally depends on a comparison of observed correlations with those predicted by a theoretical model. The sophistication with which we are able to predict such correlations has been slowly increasing. Recently, the unexpected mass distribution of merging black holes detected with LIGO/VIRGO/Kagra has encouraged cosmologists to consider early-universe scenarios in which nontrivial dynamics somehow cause a spike in power over a narrow range of scales. The enhanced fluctuations associated with these scales could collapse to produce the population of black holes observed by LVK.
  
  In these scenarios, back-reaction can cascade power from small scales to large scales. In theoretical calculations this manifests as a sensitivity to loop corrections. These are much the same as the familiar loops in Feynman diagrams that mediate quantum effects for particles scattering in vacuum, although here they can represent a mix of quantum and classical processes. Otherwise there are many points of similarity. In particular, in perturbation theory, the loops need to be regularized and renormalized. There is still considerable ambiguity about how this should be done.
  
  Although activity in this area has been catalysed by the LVK results, but the impact of loops is not limited to these scenarios. Theorists had already been studying them for a variety of applications. Depending on your interests, there could be a number of projects in this area:
  
  Numerical: if you have good computing skills (or want to develop them), then evaluation of the loops is numerically challenging. We are trying to produce high-quality numerical results for the gravitational wave spectrum  generated from loops that average over the effect of small-scale structure. This is expected to be a relevant target for LISA and subsequent gravitational wave observatories. To do this we need to build sophisticated High Performance Computing (HPC) codes that deploy on a compute cluster. Sometimes we also leverage tools from data science, including large databases and tools such Arrow for handling out-of-memory datasets.
  
  Theorists: Much progress has been driven by importing (or rediscovering) methods from non-equilibrium quantum field theory. We are exploring the use of these frameworks to write (and solve) evolution equations for cosmological correlation functions beyond tree level. We would like to use these equations to develop improved modelling of gravitational wave production and scalar back-reaction. Non-equilibrium methods have very wide applicability to many phenomena operating over cosmological history. In addition, we are exploring how to correctly regularize and renormalize the resulting correlation functions, so that they can be correctly compared with observation. There would be opportunities to become involved with this effort.

  For more information/to apply for these projects, please contact Prof. David Seery.

• Constraining the cosmological model with next generation large-scale structure surveys: Robert Smith*
  

  We are on the brink of a revolution in our understanding of the Universe with the unfolding of two large galaxy surveys, the Rubin Telescope's legacy survey of space and time (LSST), and ESA's Euclid Mission. These surveys will enable us to map the positions and properties of tens of millions of galaxies across a significant fraction of the sky and out to depths of the order roughly 10 billion years into the past, thus covering a significant fraction of the observable Universe. This data will enable us to shed new light on the mysterious dark energy that causes the expansion rate to accelerate and the dark matter phenomenology. To constrain these physical processes we will make use of statistical measures such as the galaxy clustering statistics and the weak lensing correlations.

  However, to accurately interpret this data, we will need to control a number of systematic effects to a high precision and also take our modelling of the observables to new heights. In particular, the nonlinear evolution of structure, redshift space distortions and galaxy biasing.

  I have various open PhD projects that range from: developing new theoretical tools, like the halofit code, for interpreting the nonlinear matter power spectrum required for observables that can be embedded into parameter space samplers, like Kobaya; to exploring and creating new weak lensing observables; to performing state-of-the-art numerical simulations of cosmic structure formation on some of the largest super computers. These simulations enable us to build mock Universes and explore the complex nonlinear physics and observational effects that we need to understand precisely for an accurate interpretation of the data.

  We are active members of the Rubin Telescope's LSST mission, Euclid and 4MOST. We are also part of the Virgo Consortium and so have access to the DiRAC framework and the COSMA8 supercomputer and through Euclid we have access to IRIS. The university of Sussex also has its own in house super computer called Artemis. 
  Please contact Prof. Robert E.Smith if you have questions about the project. 

• Exploring the Distant Universe with the James Webb Space Telescope: Stephen Wilkins* 

  Over the past decade the Hubble Space Telescope has collected extremely sensitive observations of the Universe. These observations have revealed a population of intensely forming galaxies present when the Universe was less than 10% of its current age. With the imminent/recent [depending what side of the launch you are reading this] of the James Webb Space Telescope (JWST) it will soon be possible to both extend samples to earlier periods of the Universe’s history but also robustly measure their physical properties.

  In this project you will analyse observations obtained by JWST to study galaxies in the early Universe from one of several surveys which the Sussex team is involved. Specifically you will focus on 1) identifying galaxies at z>7 2) measuring their physical properties (stellar masses, star formation rates, metallicities, etc.) and 3) compare against theoretical models and simulations.

  The project will make widespread use of Python but advanced prior knowledge is not critical. In addition to attendance at national and international conferences it is expected thatyou will visit collaborators in the United States and you may be required to undertake some observing duties for follow-up studies. For further information please contact Prof. Stephen Wilkins.

• Simulating the First Galaxies: Stephen Wilkins*

  Understanding first light - the formation of the first stars and galaxies in the early Universe - remains a fundamental and challenging frontier in extragalactic astrophysics. While remarkable progress in both observations and theory has been made a number of fundamental questions remain unresolved, including: the nature of the faint galaxy population, the role of nascent black holes, the evolution and influence of dust, the energetics and duration of reionisation, the development of structure and detecting the first stars.

  Owing to the increased sensitivity, areal coverage, wavelength range, and spectral/spatial resolution of forthcoming ground- and space-based observatories, this decade will see significant advances leading to strong constraints on galaxy evolution and formation models. In order to fully exploit the constraining power of observations from JWST, Euclid, Roman, SKA and the ELTs we commenced upon an ambitious simulation project: the First Light And Reionisation Epoch Simulations (FLARES).

  FLARES utilises hydrodynamical simulations which self consistently model the dark matter, gas, stars, and black holes. In this project you will contribute to the second phase of the FLARES project. This will involve running new simulations, analysing their results, and comparing against observational datasets.

  The project will make widespread use of Python but advanced prior knowledge is not critical. The project may also involve learning and using c, which is used for the core simulation codes. In addition to attendance at national and international conferences it is expected that you will visit collaborators in Europe and/or the US. For further information please contact Prof. Stephen Wilkins.

* These projects are only taking fully self-funded students, no STFC-funded places.

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