Cosmology PhD projects
Research projects on offer in our Cosmology Group:
Constraining dark energy and gravity models with the Dark Energy Spectroscopic Instrument (DESI) and the Euclid satellite
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Join a groundbreaking project at the forefront of cosmology, where you'll explore the mysteries of dark energy and test the very foundations of gravity. Using cutting-edge data from DESI and the Euclid satellite, you'll help answer one of the biggest questions in modern science: What drives the accelerated expansion of the Universe? This project focuses on testing General Relativity and alternative models of gravity, along with theories of dark energy and cosmic inflation. Since understanding the Universe’s expansion requires understanding gravity, modifications to gravity on cosmic scales have been proposed as potential explanations for dark energy. Your research will play a key role in testing these ideas. You will develop an advanced analysis pipeline to measure the anisotropic galaxy clustering signal, applying it to the largest galaxy redshift survey datasets available, from DESI and Euclid. Your goal will be to extract vital information about gravity on cosmic scales and compare your results with theoretical predictions from different gravity models. This project offers flexibility, allowing you to engage in both theoretical and computational work. You could dive into perturbation theory to refine models of the galaxy power spectrum and bispectrum or use state-of-the-art neural network-based emulators to model these statistics. You’ll also engage in high-performance computing, implementing estimators for the power spectrum and bispectrum and optimizing them for speed and efficiency using parallel computing libraries like MPI. Experience with a higher-level programming language (e.g. Python) is expected, but you will quickly pick up the skills needed for using supercomputers. You’ll be working within the global DESI and Euclid collaborations, with opportunities to attend international meetings and engage regularly with teams worldwide via Zoom. This is your chance to make significant contributions to two of the most exciting and ambitious projects in cosmology today!
Some publications about cosmological analysis with galaxy redshift surveys:
DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations - Adame et al. arXiv:2404.03002 (2024)
Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies - Eisenstein et al.; ApJ, 633, 560-574 (2005)
The Galaxy Power Spectrum and Bispectrum in Redshift Space - Desjacques, Jeong & Schmidt; JCAP, 12 (2018)
Novel analyses of galaxy redshift surveys
TBD
Cosmology with the Kinematics of Galaxies
Yan-Chuan Cai and Jorge Peñarrubia
On the very large scales of the Universe, galaxies are co-moving with the Hubble expansion, and therefore, they are moving apart from each other. On relatively small scales, fluctuations in matter density induce peculiar velocities. The total kinematics of galaxies are driven by the competing forces of the Universe's expansion and the fluctuations in local matter densities, encoding rich cosmological information. This project aims to exploit the cosmological information derived from the velocities of galaxies at small scales. We will employ the existing modelling framework of the "perturbed Hubble flow" (https://arxiv.org/abs/1405.0306) to simultaneously model peculiar velocities and the Hubble expansion. We will push the accuracy to higher levels for measuring cosmological parameters. Cosmological simulations will be utilised in the development and testing of the model before applying it to analyse public data from peculiar velocity surveys to constrain cosmology.
References:
https://arxiv.org/abs/2209.11238
https://arxiv.org/abs/1405.0306
A new era in cosmology: Euclid’s data revolution
Dr Benjamin Giblin and Prof Andy Taylor
It is an extremely exciting time for cosmology. The 2023 launch of the Euclid Space Telescope, an instrument which was specifically designed to measure the weak gravitational lensing and clustering of galaxies, heralds a new era of investigation into the dark side of our Universe. The unprecedented quality and volume of Euclid’s data will enable cosmologists to precisely constrain the nature of dark matter and dark energy, and to rigorously test for deviations from our accepted model of gravity, general relativity.
In this PhD, the student will contribute to key project analyses of the first data releases from Euclid. This will involve developing methodology for verifying the robustness of this exciting new data set, including (but not limited to): using Bayesian statistics to constrain cosmological parameters, estimating and calibrating photometric galaxy redshifts, developing new weak lensing statistics based on machine learning, and quantifying the impact of systematics like intrinsic galaxy alignments and baryonic feedback.
The student will join the Euclid Consortium (EC), a friendly and international group of multi-disciplined scientists and engineers. The EC is about to write the next page in cosmological history, and this PhD provides the student with an opportunity to make important contributions.
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.
This is one of two coordinated PhD projects here in Edinburgh focussed on Euclid’s cosmological science (see also the project directly below).
Probing the Dark Universe with Euclid
Dr Alex Hall and Dr Naomi Robertson
Euclid, a space telescope launched in 2023, is currently undertaking a galaxy survey of unprecedented size. Accurate positions and shapes of these galaxies will be used to constrain cosmological models, using the methods of weak gravitational lensing and galaxy clustering. While the main aim 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. Specific project ideas include improving the robustness of neutrino mass constraints with a geometry-growth split, using weak lensing three-point statistics to constrain intrinsic galaxy alignments and feedback processes, developing a new modelling pipeline for weak lensing using Effective Field Theory, and using cross-correlations with the CMB to probe large-scale matter flows. 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.
This is one of two coordinated PhD projects here in Edinburgh focussed on Euclid’s cosmological science (see also the project directly above).
Under the Computational Astrophysics projects, see also:
- Precision cosmology with the Lyman-Alpha forest - Avery Meiksin