Fast radio bursts (FRBs) are millisecond-duration extragalactic transient events, so powerful that they can be detected after travelling more than half the age of the Universe to reach Earth. Currently, the origin of FRBs is unknown, although lead theories include young, rapidly rotating, and highly magnetised neutron stars; and the merger of compact objects such as a neutron star and a white dwarf. Critically, the frequency dependent time-delay induced as an FRB passes through ionised gas measures the total column density of that gas. Known as the ‘dispersion measure’ (DM), this delay allows FRBs to be used as probes of the structure of matter in the Universe.
Simulations of the cosmological evolution of matter in the Universe are required to help interpret these observations. Such simulations trace the evolution of cosmic structures, from filaments and voids down to galaxy scales, and model the growth of galaxies via their accretion of gas, formation of stars, and the feedback from supernovae and black hole growth that ionises and expels gas into their surroundings. In particular, they predict the abundance and location of diffuse ionised gas which is otherwise impossible to probe. Coupling these simulations to FRB observations then allows FRBs to probe this invisible component of our Universe.
Aim
The aim of this project is to use cosmological simulations to simulate the dispersion measures expected from FRBs emitted across cosmic time. Existing simulation suites – such as IllustrisTNG and SIMBA – will be used to predict how observed FRB DMs correlate to cosmic structures. Coupled with both real and simulated FRB observations, this will answer questions such as: how much matter exists in the circum-galactic medium vs the intergalactic medium? What is the evolution of ionised gas around FRB host galaxies? At which mass scales do feedback processes expel gas from Galactic halos? How does turbulence in Galactic halos bias our FRB observations? The project will be conducted in concert with the CRAFT Collaboration, which is centred on Perth, Melbourne, and Sydney. Collaboration with cosmology experts at the University of WA, Edinburgh, and Tokyo is also expected.
Objectives
The objectives of this project will be to use existing methods for measuring the DM along the line of sight of cosmological simulations, and extend these results to new applications. In the next decade, large-scale FRB surveys will be combined with broad optical surveys to provide extensive catalogues of galaxies with spectroscopic and/or photometric measurements. This project will develop methods for using such catalogues to constrain fundamental unknowns about our Universe. This will include our latest knowledge of intrinsic FRB properties and detection biases, combined with parameters of optical surveys. Early results can be tested against FRBs detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), combined with optical data from the Dark Energy Survey. In the latter part of the PhD, it may be possible to use Vera C. Rubin’s Legacy Survey of Space and Time (LSST), combined with precise localisations from ASKAP and MeerKAT FRBs.
Significance
Fast radio bursts were only confirmed to exist in 2013. They are the brightest radio transients in the Universe – so bright, that they can be seen from over eight billion years ago, when the Universe was less than half its current age. By measuring the column density of ionised gas, FRBs have the ability to probe the structure of the Universe, promise to resolve the current Hubble tension, and detect the otherwise invisible hot gas surrounding galaxies. Provides a brand new tool for probing long outstanding questions about the structure of our Universe, from galaxy scales and upwards
As part of the International Centre of Radio Astronomy Research (ICRAR), the Curtin Institute of Radio Astronomy founded the CRAFT project to detect FRBs with ASKAP back in 2008, and in 2020, Curtin’s A/Prof Jean-Pierre Macquart established the redshift-DM relation now known as the Macquart relation in his honour. This project will link the student to both this exciting new field, and established astronomical methods in large-scale surveys and cosmology.
Ideal Candidate
We are looking for a self-motivated PhD applicant who is interested in supercomputing, with a background in quantitative sciences (an astronomical background is preferred but not required), and an eye for detail.
Additionally, the applicants should meet the eligibility criteria for entry into a PhD program at Curtin University.
This project is open to International and Domestic applicants.
Scholarship
If you are identified as the preferred candidate for this project, you may be considered for an RTP scholarship.
Enquires and How to Apply
For enquires about this opportunity contact Associate Professor Clancy James at Clancy.James@curtin.edu.au
To formally apply submit an Expression of Interest to Associate Professor Clancy James during the Central Scholarship round (July 1st – July 31st 2026)