Cosmology PhD projects
Research projects on offer in our Cosmology Group:
Cosmology in the era of galaxy surveys and gravitational waves
With stage-IV galaxy surveys now taking data and third-generation gravitational wave detectors on the horizon, we will be entering the new era of high-precision cosmology with multiple observables, galaxies and gravitational wave sources. One of the primary cosmological probes to date is weak lensing by the large scale structure. The shape of distant galaxies is distorted by the gravitational potential of the distribution of matter along the line of sight. Similarly, the path that gravitational waves take will also be changed, inducing a magnification effect such that the sources may appear closer than they really are.
In the context of cosmology in the coming decade, gravitational wave lensing has emerged as a novel approach, which illustrates the huge potential of interdisciplinary studies. The PhD project will focus on identifying potential ways to constrain cosmology from the combination of galaxies and gravitational ways in current or near-future data. In particular, one of the research projects would be the study of cross-correlations between gravitational waves (currently detected by second-generation detectors) and galaxies that are being observed by Euclid as part of data release 1 and 2. This would also include the characterisation of systematic errors.
The ideal candidate would be keen to explore new probes with different datasets, have a taste for scientific challenges, and have good skills in statistics and data analysis. The successful candidate will have the opportunity to grow a strong research portfolio, build strong scientific skills, and join the Euclid consortium, a vibrant community of more than a thousand scientists across the world. Also, they will have access to Euclid data, be involved in the activities of the gravitational wave working group, lead science projects, and have the opportunity to join other groups.
Weak lensing and galaxy clustering with Euclid
Euclid, a European Space Agency space telescope launched in 2023, is currently conducting a galaxy survey of unprecedented size. Accurate positions and shapes of over a billion galaxies will be used to constrain cosmological models, using the methods of weak gravitational lensing and galaxy clustering. While the main aim of the mission is to pin down the physics of Dark Energy, Euclid data will be able to place tight constraints on a range of extensions to the standard cosmological model as well as astrophysical processes that impact Dark Matter clustering.
In this PhD project, the student will develop new methodology to extract precise and accurate cosmology constraints from Euclid weak lensing and clustering data, with a focus on the second data release from Euclid, DR2.
Specific projects include measuring cross-correlations of Euclid data with ground-based galaxy clustering and lensing surveys, developing and performing internal consistency tests with data splits, and measuring galaxy clustering induced by cosmic magnification. There will be opportunity to apply methods to new data from Euclid and be involved in a cutting-edge cosmology mission.
The student will be part of the Euclid Consortium, a vibrant and diverse international collaboration tasked with performing the main science analysis of Euclid. There will be ample opportunity to attend conferences and present work. The project will be a mixture of theoretical, computational, and data analysis work. It is desirable to have taken a cosmology course and to have experience with Python.
Cosmology Theory Meets Data: Modelling Techniques For Dark Energy Experiments
State-of-the-art cosmological surveys like the ongoing Euclid satellite mission are promising to map the large-scale structure of the Universe and pin down the nature of dark energy.
This PhD project aims to tackle one of the biggest challenges in theoretical and observational cosmology: how to model accurately and efficiently the nonlinear (that is, small scale) behaviour of exotic dark energy and modified gravity models. The student will gain experience in theoretical and observational cosmology, dark energy theory, numerical methods, and will be part of a vibrant international community of scientists. The student will be involved in analysing Euclid data and interpreting the results.
The project will be a mixture of theoretical, computational, and data analysis work. It is desirable to have taken a cosmology course and to have experience with Python.
Lensing and clustering with the Vera Rubin Observatory
Weak lensing and the clustering behaviour of galaxies offer us a uniquely powerful way to probe the nature of dark energy and dark matter, the history of the Universe, and the laws of gravity. The Vera Rubin Observatory will carry out a 10-year survey that will image billions of galaxies to high redshift over half the sky, providing an unprecedented dataset for studying these observables. The first Rubin preview data will be ready for this project, and the full first year data set should be available part way through it.
Edinburgh is heavily involved in Rubin, and I lead the team measuring the primary cosmological observables: the two-point correlations of lensing and clustering. These quantities encode the statistics of the density fields of the Universe, and we can measure them from the high density galaxy catalogs that we get from Rubin. In this PhD you will run the computational project measuring validating, and modelling the two-point statistics from this powerful new data set.
This will involve extensive code development, data science and visualization, and high performance computing. You'll be working with a large international team.
Under the Computational Astrophysics projects, see also:
- Precision cosmology with the Lyman-Alpha forest - Prof Avery Meiksin
Under the Galaxy Formation & Evolution projects, see also:
- Illuminating the Universe with the First Galaxies and the James Webb Space Telescope - Dr Laura Keating