[STFC Studentship] Massive galaxies and their circumgalactic medium in cosmological simulations

Galaxies live in large, dark matter-dominated, quasi-spherical structures called haloes. The gaseous com- ponent of these haloes is also known as the circumgalactic medium (CGM) and comprises the reservoir of material from which the embedded galaxies can grow. Galaxies do not only passively accrete gas from their environment, they also drive large-scale outflows into the CGM. These outflows enrich the CGM, magnetize it, and drive shocks and turbulence. Therefore, if we wish to understand the evolution of galaxies, we need to study the CGM. This PhD project will focus on the environments of galaxies more massive than the Milky Way. Such massive haloes are expected to host volume-filling hot gas with temperatures close to the virial temperature, which increases with halo mass. Radiative cooling allows some fraction of the gas, especially dense or metal-rich gas, to cool down to much lower temperatures. This creates a multiphase medium where the hot, diffuse gas and the cooler, denser gas are in approximate pressure equilibrium. The massive galaxies themselves behave very differently to lower mass galaxies, because they no longer rapidly grow and have mostly switched off star formation, a process known as quenching. Observations of the CGM have shown a large reservoir of cool gas even around galaxies with no cold interstellar medium or ongoing star formation. This came as a surprise: why does this cool gas not accrete onto the central galaxy and fuel star formation? These observations have thus led to the suggestion that our theoretical understanding is incomplete.

This project will use cosmological, magnetohydrodynamical simulations, which start when the universe was very young and follow not just the formation of galaxies but also the large-scale structure of the universe. Traditionally, such simulations focus most of their computational effort on creating the best galaxies and incorrectly assume that the treatment of the CGM is sufficiently accurate. New numerical methods are being developed in order to increase the resolution of the gas around galaxies and study the massive galaxy haloes in more detail than has ever been possible before.

The PhD student will take charge of developing and running galaxy simulations with enhanced CGM resolution and investigate the importance of various physical processes, such as magnetic fields and thermal conduction. They will have the opportunity to exploit the simulation data to study gas accretion, large-scale outflows, chemical enrichment, and other properties of the CGM. By comparing their simulations to existing observations and making predictions for future observations, the PhD student will be able to reveal the crucial role the CGM plays in the formation of massive galaxies and to put galaxy formation models to the test.

 Eligibility  

The typical academic requirement is a minimum of a 2:1 physics and astronomy or a relevant discipline. 

Applicants whose first language is not English are normally expected to meet the minimum University requirements (e.g. IELTS 6.5 Overall with 5.5 minimum in sub-scores) (https://www.cardiff.ac.uk/study/international/english-language-requirements) 

How to apply 

Applicants should apply to the Doctor of Philosophy in Physics and Astronomy with a start date of 1st October 2023. 

Applicants should submit an application for postgraduate study via the Cardiff University webpages (https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/physics-and-astronomy) including: 

• your academic CV 

• Your degree certificates and transcripts to date including certified translations if these are not in English 

• a personal statement/covering letter 

• two references, at least one of which should be academic. Your references can be emailed by the referee to [Email Address Removed]  

Please note: We are do not contact referees directly for references for each applicant due to the volume of applications we receive.     

In the "Research Proposal" section of your application, please specify the project title and supervisors of this project. You can apply for up to three of our advertised STFC projects by listing them in order of preference in the free text area of the "Research Proposal" section of the online application form. 

In the funding section, please select that you will not be self-funding and write that the source of funding will be STFC. 

Once the deadline for applications has passed, we will review your application and advise you within a few weeks if you have been shortlisted for an interview.