Potential PhD Topics

Modern radio telescopes generate up to Terabytes of data every second that needs to be captured and transformed into scientific products. This is done by a combination of specialist chips, high-bandwidth network connections, and moving vast amounts of data from memory via various buses to a combination of Field Programmable Gate Arrays, GPUs and CPUs. We are seeking a PhD student with either a knowledge of signal processing techniques or coding skills that will operate at the interface between science and instrumentation to accelerate discovery in Fast Radio Bursts or Pulsar astronomy and to help us reduce our carbon footprint. The student will participate in projects that make use of both signal processing and machine learning using the Molonglo telescope, the Australian Square Kilometre Array Pathfinder (ASKAP), the MeerKAT radio telescope and the Parkes 64-m observatory. Prototyping will be done on the OzSTAR supercomputer and in partnership with Nvidia.

Image Caption: The OzSTAR supercomputer has over 260 GPUs for cutting edge signal processing techniques and radio astronomy discoveries.

The Keck Wide-Field Imager – an exciting opportunity for a software-minded student

Supervisors: Prof. Jarrod Hurley and Prof. Jeff Cooke

This project is an opportunity to be involved in the development of the Keck Wide-Field Imager (KWFI) instrument which will be installed on the Keck Telescopes in Hawaii. KWFI will be the most powerful wide-field optical imager on Earth or in space for decades, facilitating a vast array of science goals, including follow-up to gravitational wave detections. The build team for the instrument will be led from CAS and this PhD project offers the opportunity to be a high-profile member of the build team from the early stages of the project, focusing mainly on the software development aspects.

KWFI will bring together an array of technology and manufacturing innovations – across optical, opt-mechanical, Industry 4.0 (digital twin and smart sensors), composite material and software engineering areas – to develop the world’s first smart instrument. The software engineering will include development of the instrument control software for the filter exchange mechanism and other components of the instrument, such as the data reduction pipeline. On these aspects you will work closely with a team of professional software developers at Swinburne to learn best practice in build environments, software optimization, accelerated computing and testing, for example, while becoming an expert in a vital role within astronomy. If you like writing software, working in a team to develop new innovative techniques and being part of an exciting science program, we would like to hear from you.

Caption: The Keck Observatory.

Immerse yourself in the amazing realm of stars, binaries and star clusters

Supervisors: Prof. Jarrod Hurley

Star, binaries and star clusters are the fundamental building blocks of galaxies and underpin much of what we know about astronomy. Star clusters, in particular, are fascinating laboratories in which to study the mix of stellar, binary and dynamical evolution - with this mix expected to produce much of the stellar exotica that we observe, e.g. blue stragglers, X-ray binaries and mergers of neutron stars and black holes that produce gravitational waves. To model star clusters and their populations we have a direct N-body code and associated stellar/binary population synthesis codes available to run on the OzSTAR supercomputer to investigate a range of potential projects. If you are interested in pushing the boundaries of how stellar populations form, evolve and interact, please get in touch to discuss potential projects. These projects can be designed to cover a range of skillsets and interests, from confronting observations with model data to developing machine learning algorithms to constrain the astrophysical parameter space, to name a couple of examples.

Image caption: An illustration of a binary star system within a globular cluster. Credit: Mark A. Garlick/University of Warwick.

Detecting and characterizing transient gravitational wave sources

Supervisors: Dr. Jade Powell

The LIGO and Virgo gravitational wave detectors have discovered several signals from the mergers of binary black holes and neutron stars. Many more gravitational wave events are expected as the detectors begin their fourth observing runs next year. This project will focus on improving our knowledge of transient gravitational wave signals by detecting and characterizing their sources. The project will also contribute to the science case for the next generation of gravitational wave detectors, as more sensitive detectors will present new data analysis challenges for the detection of transient gravitational wave sources.

Caption: Catalogue of all gravitational wave detections from 2015 to 2020. Credit: Carl Knox, Swinburne/OzGrav-ARC Centre of Excellence.

Probing the cosmic web with Fast Radio Bursts

Supervisors: A.Prof. Ryan Shannon, Prof. Adam Deller, and Prof. Matthew Bailes

Fast radio bursts are an enigmatic population of transient astronomical events that are promising to be a revolutionary astrophysical tool. The bursts are exciting because they both represent a brand new and unprecedentedly luminous radio transient but are also now demonstrating the ability to uniquely probe the cosmology of the Universe. This project will utilize the wild field of view of the Australia Square Kilometre Array Pathfinder (ASKAP) to rapidly increase the population of the bursts and identify hosts, emission mechanisms and explanations for the bursts. ASKAP has proven itself to be a reliable FRB detection machine and localization machine, able to pinpoint burst locations to within galaxies. The localisations have been used to study the intergalactic medium and find the Missing Baryons . In the next year we will be developing a new FRB detection system for ASKAP that will increase its burst detection rate by a factor of 10.

Your project, which would be undertaken as part of the Commensal Real Time ASKAP Fast Transient collaboration could include:

Develop novel methods and pipelines to detect bursts in real time.
Study the demographics of the burst population, and synthesizing with discoveries made at other facilities.
Determine the magneto-ionic properties of the intergalactic medium and host galaxies for FRBs.
Conduct multi-wavelength campaigns to identify hosts and counterparts to the bursts as part of our ESO VLT Large Project.

Specific contributions will depend on your interests. In addition, you will also gain hands-on experience with ASKAP. Through all the of the Ph.D. you will gain experience with computation and signal processing while doing cutting-edge astrophysics.

Caption: The Australian Sqare Kilometre Array Pathfinder, located in outback Western Australia, is a radio array of 36 antennas. Credit: Alex Cherney/CSIRO.

Hunting for supermassive black holes with gravitational waves and pulsar timing arrays

Supervisors: A.Prof. Ryan Shannon and Prof. Matthew Bailes

Supermassive black holes - black holes that are billions of times more massive than the Sun, are thought to reside in the Centres of most galaxies. Binary supermassive black holes, produced when galaxies merge, are thought to be the loudest emitters of ultra-low nanohertz-frequency gravitational waves. These gravitational waves can potentially be detected by observing an ensemble of ultra-stable millisecond pulsars (a pulsar timing array) with the most sensitive radio telescopes on Earth. The breakthrough detection is anticipated within the coming years.

In this project, you will develop advanced algorithms to search for gravitational wave signatures in pulsar timing array data sets. Using the OzStar supercomputer, you will apply these methods to world leading pulsar timing sets, including that from the Swinburne led MeerTime Pulsar Timing Array and the International Pulsar Timing Array. You will interpret the implications of the detections in the context of models of galaxy formation and evolution.

Caption: The 64-dish MeerKAT telescope in South Africa will be extended to form the 196-dish Square Kilometre Array and is used by Swinburne to pioneer signal processing techniques for radio astronomy.

Discovering the origin of gravitational waves

Supervisors: Dr. Simon Stevenson

Gravitational waves from colliding neutron stars and black holes are now being observed on a regular basis. The signals encode information about the masses and spins of the objects, which we can use to learn about how these objects formed. Some questions are starting to be answered: we now know that pairs of neutron stars and black holes (in all permutations) exist and merge in the universe, we know roughly how often these mergers happen, and we know roughly what the masses of black holes are. What we currently don't know is how these compact binaries form in the first place. This project aims to make theoretical predictions for the properties of gravitational wave mergers originating from a variety of different astrophysical scenarios (such as binary evolution and star clusters) using a suite of state-of-the-art modelling tools such as COMPAS, NBODY7 and MESA. These predictions will then be compared to the ever growing population of observed gravitational waves in order to uncover their origins.

Caption: A pair of interacting massive stars (VFTS 352) that may eventually form a pair of merging black holes. Credit: ESO/L. Calçada.

The following projects are available as part of the 2023 RTPS round. Applicants are encouraged to contact supervisors to express interest:

The habitats of the nearest groups in the universe

Supervisor: A.Prof. Michelle Cluver

The galaxies that reside in local large scale structures provide a unique opportunity to study the most recent mass assembly in our Universe. As groups coalesce into clusters, which in turn become assimilated into superclusters, the local universe provides us with a snapshot that encodes how the baryon cycle of a galaxy is being influenced by its habitat. The closest structures provide the most complete view of the mechanisms at work, down to the lowest galaxy masses. In this project we will combine a new state-of-the-art group catalogue from the 2MASS Redshift Survey with stellar mass and star formation measures from the WISE mid-infrared survey, to study how galaxies and groups are pre-processed in the southern large scale structure region spanning the Pavo-Indus Supercluster and the Eridanus and Fornax Clusters.

Does environment matter and should we be worried if it doesn’t?

Supervisors: A. Prof. Michelle Cluver

Understanding how galaxies are potentially shaped by their small-scale environments and/or their situation within large-scale structure requires us to separately test the impact of each. This allows us to determine if and where the evolution of a galaxy is being influenced by external factors, crucial to identifying the relevant physical mechanisms at work (or play?). Our team has curated a bespoke mid-infrared photometry catalogue for z<0.1 galaxies within 384 square degrees of the KiDS-S region, using data from the WISE telescope. Combining the resulting measures of star formation and stellar mass with state-of-the-art characterisation of local and large-scale structure environment, we can look for signatures of pre-processing, and isolate/characterise potential sites of transformation. These sites will be prime targets for follow-up observations using the SKA Pathfinders.

Early galaxy formation and massive galaxy death

Supervisors: Prof. Darren Croton

This project will use state-of-the-art galaxy formation simulations and models to understand the formation and death of massive galaxies at high redshift. It will focus on the time covering the end of reionisation and cosmic dawn (z~6) until the peak of the first great wave of star formation at cosmic noon (z~2). This is a key moment for the Universe, where observations have recently revealed the death of very early forming massive galaxies. The existence of mature massive galaxies at these early times and how they came to be remains a mystery. The fact that we see such galaxies so early in the Universe is remarkable.

This PhD will collaborate with researchers from the ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D) and connect to new observations from the James Webb Space Telescope, bridging theory and observation. The PhD student will lead a team of international researchers in unravelling this mystery.

Image caption: The Uchuu cosmological simulation, within which hundreds of millions of galaxies and black holes can be studied (credit: Tomoaki Ishiyama).

Imaging and modelling the aftermath of gravitational wave mergers

Supervisor: Prof. Adam Deller

This project aims to capitalise on the dawn of the era of gravitational wave astronomy by studying the radio afterglows that result from gravitational wave merger events in minute detail. When two compact objects (one neutron star plus a second neutron star or a black hole) merge, a burst of gravitational wave emission is released, and a violent outflow is launched that can lead to pan-chromatic electromagnetic emission. By studying the radio emission of the outflowing material, we can determine both the characteristics of the outflowing material, and the viewpoint from which we are seeing the system. Twin inputs are required: 1) ultra-high resolution radio images obtained with intercontinental radio interferometers, and 2) highly sophisticated computational models of the merger. To date, this has been performed for just one system, the famous NS-NS merger GW170817, for which our team showed that the merger launched a powerful and narrowly collimated jet of material (Mooley, Deller, et al., Nature, 2018). In the near future, as LIGO/Virgo detects many more NS mergers, we anticipate applying these techniques to an increasing sample of systems, recovering information about the merger events that cannot be obtained from the gravitational wave data alone and also improving on "standard siren" measurements of the expansion of the Universe. The successful candidate will work with Prof. Adam Deller and an ARC-funded postdoctoral researcher, along with international project partners at Caltech and Tel Aviv University, focusing on the comparison between radio interferometry data and hydrodynamical models to extract physical parameters of the merger afterglow.

Image caption: Model (left) and VLBI data (right) of the radio afterglow of the NS-NS merger event GW170817 (Mooley, Deller, et al., Nature, 2018). By comparing the VLBI data to a range of hydrodynamical and analytic models, we were able to constrain the viewing geometry of the system and the jet parameters.

How do exploding stars reshape galaxy evolution?

Supervisors: A.Prof. Deanne Fisher

Supernovae are among the most energetic events in the universe, typically outshining the galaxy they occur in. While very uncommon in our own Milky Way, supernovae happen very often in so-called ``star-burst” galaxies that are making new stars at 10-100 times the rate of the Milky Way. In these galaxies, clusters of supernovae explode in the disk, the combined energy and momentum pushes gas up out of the spiral galaxy and into the halo above the disk. This changes the properties of the galaxy, and is considered by most theories to be a linchpin that regulates the growth of galaxies. We view this as faint filaments of gas that extends above star forming galaxies. In this project we will study this gas. The physical properties of the gas directly relate to the physical models of how these large outflows of gas evolve and shape outflows. We will use data from a new Large Program on the Very Large Telescope, an 8 meter telescope in Chile, to study the outflowing gas. The student will be part of an international team that includes astronomers in Germany, UK, France, USA and Australia. The student will develop skills in python and ``datacube” analysis in astronomy. At Swinburne they will work in a team of 4 HDR students and 2 postdocs, along with myself. This is a large program with scope for multiple projects of students. This field has a strong career potential as the 2020 decadal review in astronomy as the key area for extragalactic research.

Futher information:

Rupke et al. 2019 Nature
Galactic winds dictating galaxy evolution – 20-minute lecture by L. Zscaechner
How feedback shapes galaxy evolution – 1-hour lecture by Prof Christy Tremonti

Ultra diffuse galaxies

Supervisors: Prof. Duncan Forbes

In 2015 a new class of galaxy was discovered - the ghostly Ultra Diffuse Galaxy (UDG). Such galaxies have the same total luminosity as a dwarf galaxy but some reveal a halo of dark matter similar to that of a giant galaxy making them 99% dark matter! Since their discovery they remain a mystery and a challenge to theories of galaxy formation. This PhD project aims to discover more UDGs from deep imaging, determine their stellar population and dynamical properties, and compare them with the latest theoretical models. This project is an observational one, using new data from the world's largest telescopes (Keck and the VLTs) and involving colleagues in California.

Image caption: Ultra Diffuse Galaxies have the same total luminosity as a dwarf galaxy but the same total mass as a giant galaxy. Some UDGs are 99% composed of dark matter and we don't know why! (Credit: Schoening/Harvey/van Dokkum/NASA/ESA Hubble Space Telescope.

Space system real-time data fusion, integration and cognition

Supervisors: Prof. Christopher Fluke

In many application domains, human operators utilise data visualisations to identify, distinguish and classify signals from noise, and perform anomaly and outlier detection – the process of visual discovery. Increasingly, as more data is available than can be looked at by eye in real-time, new systems and strategies are being developed that rely more heavily on automation, artificial intelligence (AI) and machine learning. With a particular focus on data-intensive, real-time Space applications (including Mission Planning, Space Domain Awareness, Earth Observation, Defence and National Security), PhD Projects are available with Professor Fluke (SmartSat CRC Professorial Chair) in the following theme areas:

Human-Machine Teaming, where human performance at cognition and visualisation is enhanced when working in partnership with intelligent agents;
Visual Data Analysis, exploring new approaches to multi-modal data fusion and integration that benefit from high-performance and accelerated computing architectures to support visual discovery at scale; and
Extended Reality Visualisation and Discovery, leveraging the continued emergence of virtual reality and augmented reality to enhance insight and understanding from Space data in all its forms.

Caption: Interactive visualisation of 3D hyperspectral survey data on the Swinburne Discovery Wall (Credit: C.Fluke).

Cosmology with the Hubble Space Telescope

Supervisors: Prof. Karl Glazebrook and Dr. Colin Jacobs

Using The Hubble Space Telescope) (HST we are observing ~100 new gravitational lens systems. Of particular interest is to look for ‘double source plane lenses’ (DSPL) where a single elliptical galaxy magnifies two different galaxies at significantly different redshifts. Every DSPL provides strong constraints on the cosmological parameters via the ratio of angular distance (from lensing) to redshift, however only three ‘good’ DSPLs are known. In this PhD project we will (1) visually inspect all the HST images to make a catalog of DSPL candidates for redshift measurements (2) carry out a program of Keck observing to get spectroscopic redshifts (3) make simulations of constraints on cosmological models from large DSPL samples - with particular attention to looking at Early Dark Energy models (4) create new large DSPL samples using the critical combination of ground-based LSST+Euclid Space Telescope imaging and 4MOST survey spectroscopy.

Image caption: The top row shows 5 of our HST observed lenses. This is a program led by Swinburne, we have 52 done at the time of writing, but there are more every month and we never quite know what we are going to find. In the bottom the physical effect of gravitational lensing is illustrated and we show a zoomed view of one of our lenses with multiple sources.

The missing population of intermediate mass black holes

Artists's impression of a black hole. Credit: Gabriel Perez Diaz.

Supervisor: Prof. Alister Graham

There is a largely-missing population of intermediate-mass black holes (IMBHs) with masses higher than that formed by single stars today (M_bh=1.4 to 120 M_Sun) and less massive than the supermassive black holes (SMBHs: 10⁵—10¹⁰ M_Sun) known to reside at the centres of big galaxies. Not surprisingly, astronomers around the world are hotly pursuing the much-anticipated discovery of IMBHs. This thesis will involve several interconnected projects involving telescope and satellite image analysis and statistical techniques. Improved methods for estimating both IMBH and SMBH masses will be developed and applied, with ties to the upcoming Large Synoptic Survey Telescope expected. The coexistence of these massive black holes in dense, compact star clusters at the centres of galaxies is also expected to be a source gravitational radiation detectable by the planned eLISA satellite, for which updated predictions will be made.

Students will benefit from membership in the ARC Centre of Excellence for Gravitational Wave Discovery, OzGrav.

Galaxy Structure and massive black holes

Supervisors: Prof. Alister Graham

This project will explore how stars are distributed in galaxy images obtained from both ground-based telescopes and satellites such as Hubble and Spitzer. The structure of galaxies reveals much about how they formed, how they are connected with one another and also with the massive black holes that reside in their cores. This knowledge will be used to pursue a number of exciting topics at the forefront of astronomy. A feeling for the type of research done with Prof. Graham can be seen in his Press Releases.

Image: Artistic impression of a black hole featured on the cover of Swinburne University's 2019 annual report. Credit: James Josephides and Alister Graham.

Understanding gas flows in and around galaxies

Supervisors: A.Prof. Glenn Kacprzak and Prof. Michael Murphy

Ever wonder why some galaxies form stars while others do not? Or where does all the fuel for star-formation come from and what regulates it? The evolution of galaxies is intimately tied to their gas cycles - the gas accretion, star formation, stellar death and gas expulsion. As galaxies evolve, their gas cycles (known as feedback), give rise to an extended gaseous halo surrounding galaxies. Understanding how feedback works has become recognized as THE critical unknown process missing to fully understand galaxy evolution. Therefore, gaseous galaxy halos are the key astrophysical laboratories harbouring the detailed physics of how galactic feedback governs galaxy evolution. Observationally, galaxy halos are studied with great sensitivity using quasar absorption lines. Imprinted on the quasar spectrum are the motions, chemical content, density, and temperature of the gas. These absorption signatures provide details that are unobtainable using any other method of observation. Here, the student will join an international collaboration and will examine how the host galaxy properties are linked to their circumgalactic gas properties using Hubble Space Telescope and Keck Telescope data.

Image Caption: Cool gas (green) from cosmic filaments accretes onto the galaxy, which drives its rotation and controls the rate at which it forms stars. Star formation and supernovae expel gas back into the circumgalatic medium (purple). Background quasars are used to study these gas flows around galaxies.

Mapping electromagnetism's strength throughout the Milky Way with solar twin stars

Supervisors: Prof. Michael Murphy

The constancy of nature's laws, characterised by the fundamental constants, has been mapped out on all size-scales, from the laboratory through to the cosmic microwave background at redshift z=1100, except for one important size-scale: our own Milky Way galaxy. This project aims to make the first check on electromagnetism's strength in our Galaxy with high enough precision that a discovery of variation is possible (i.e. not already ruled out by previous, much less precise measurements). The idea is to use the spectra of solar twins – stars with spectra indistinguishable from our Sun's, and each other – as the probe because this allows for a highly differential measurement that will be immune to all manner of systematic effects that have precluded such a measurement in the past.

Depending on the status of this field at the time, there are both observational and theoretical avenues open for this position. For example, the student may either be making the first measurements on existing solar twin spectra, contributing to an effort to identify very distant solar twins, analysing new spectra of these distant solar twins, or making measurements with them. The new spectra would be taken with a new instrument on the 8-metre Very Large Telescope in Chile. Or they may be using advanced quantum mechanical calculations to determine how solar twin spectra depend on fundamental constants. These and other options will be discussed with the candidate.

Weighing the Universe with Deuterium

Supervisors: Prof. Michael Murphy and A.Prof. Glenn Kacprzak

This project aims to weigh the universe – i.e. measure the number of baryons it contains – by comparing the amount of hydrogen and its main isotope, deuterium, in distant, almost pristine clouds of gas. The baryon fraction is a fundamental quantity in cosmology, so obtaining new measurements using deuterium is essential for detecting any departures from our standard cosmological model. We observe these gas clouds in the spectra of background quasars – the super-bright accretion discs around supermassive black holes – taken with the largest optical telescopes, such as the Keck 10-metre in Hawaii and VLT 8-metre in Chile. This experimental approach is explained in the video. Cases where an accurate (and precise) measurement can be made are incredibly rare, but we have identified several new examples that could provide competitive baryon fraction measurements. The aim is to analyse these existing spectra, and obtain new spectra if required, to test the standard cosmological model. This is a collaboration with astronomers in the US (Hawaii & California) and travel to work with these collaborators is a possibility. Observations using either the Keck and/or VLT are also possible during the course of the PhD project.

Towards the dream of Galactic Archaeology

Supervisors: Prof. Michael Murphy and Dr. Chris Flynn

Our Milky Way galaxy was built up by numerous mergers of smaller galaxies over time. But reconstructing this dynamic, complex history remains a challenge. The GALAH survey, using the 4-meter Anglo–Australian telescope in Siding Spring (NSW) has almost completed its mission to observe 1 million stars in our Galaxy, as a first attempt at "Galactic Archaeology": using the detailed chemical composition of stars, plus their positions and motions, to trace them back to their origins. This dream can only be realised if the abundances of many elements – used as "chemical tags" – can be measured very precisely. Our group has recently invented new techniques that should make this possible, but we've only just begun, focussing so-far on stars very much like our own Sun. But there is huge potential! Your PhD work would push these techniques to recover much more precise, detailed chemical tags for many types of stars, not just Sun-like ones. This could make a real leap towards true Galactic Archaeology and understanding the history of our Milky Way. This will be a collaboration with GALAH astronomers, with a possibility to join that team and gain telescope observing experience.

Deconstructing observed spectral features of galaxies using machine learning techniques

Supervisors: Dr. Themiya Nanayakkara , Dr. Colin Jacobs , and Prof. Karl Glazebrook

Galaxy spectra are analogous to a human fingerprint or to DNA of living organisms. Spectral features of galaxies contain a wealth of information about the nature of the stars and gas in galaxies. Most of our understanding of galaxies in the observed universe has been obtained by dissecting these spectral features and comparing with theoretical models. However, there are large shortcomings in current modelling of certain emission lines that are expected to originate from a variety of sources. This project will combine state-of-the-art theoretical models, machine learning techniques, and deep observations of the early Universe from novel ground based instruments such as VLT/MUSE, Keck/KCWI and future space based telescopes such as the James Webb Space Telescope. In this project, stellar atmospheres with photoionisation and 3D radiative transfer codes will be used to generate a suite of observed spectral features of galaxies. By using machine learning techniques on the developed models, emission features that are crucial to constrain the far-UV ionising continuum of the stars and the nature and geometry of the gas in galaxies will be identified. Then these predictions will be used on observed galaxy data to probe the nature of galaxies in the very early Universe. This will be a timely project that will combine the wealth of ground based public data that are being made available by current deep spectroscopic surveys of the Universe, with future observations from the James Webb Space Telescope which is expected to be launched in 2021.

Exploring the massive stars in cosmic noon with the MAGPI survey

Supervisors: Dr. Themiya Nanayakkara , and Prof. Karl Glazebrook

The ~2 billion year time window between 2<z<4 is one of the most active phases in cosmic evolution. Galaxies in this epoch were evolving rapidly and actively forming most of the observed baryonic mass in the Universe. Constraining the types of the stars and the properties of the inter-stellar-medium (ISM) of these galaxies is of great importance to determine how the most of the observed mass of the Universe was formed. The light from these galaxies are expected to be dominated by massive blue stars, thus their imprints can be observed in the rest-UV part of the galaxy spectrum. The rest-UV has strong emission lines that can provide a wealth of information about the ionising spectra of the stars, ISM conditions, and the neutral hydrogen geometry.

In this PhD project you will use data from the MAGPI survey, a VLT MUSE large program to explore the rest-UV emission line properties in the z>2T Universe. With this project, you will be able to join the MAGPI team https://magpisurvey.org and analyse the deep emission line sources observed in the Universe to demystify properties in the early Universe. During the second part of the PhD, the access to a wealth of rest-frame optical spectra of galaxies with the James Webb Space Telescope will mean that you will be able to extend the analysis further by combining data from deep MUSE surveys with that of JWST to get a comprehensive understanding of stellar populations in this cosmic window.

Connecting galaxies to their larger dark matter halos: the stellar-to-halo mass relation

Supervisors: A.Prof. Edward (ned) Taylor

We now understand every galaxy to form and reside at the centre of a larger, diffuse halo of dark matter. As far as we know, the properties of dark matter are very simple: no interactions with itself or other matter except through gravity. This makes dark matter easy to model, but very difficult to observe. By contrast, galaxies are easy enough to find and measure, but disentangling the many and varied mechanisms that influence their formation and evolution is a wicked problem. As the conceptual link between the observed galaxy population and the cosmological population of dark matter halos, the stellar-to-halo mass relation represents a crucial interface between observation and theory: especially in how models are calibrated and/or validated.

The focus of this project will be to map out the connection between galaxies and their halos — that is, the stellar-to-halo mass relation — by combining dark matter statistics from large cosmological simulations with statistics of the galaxy population in the local universe. The work will include measuring the number of galaxies in the nearby Universe as a function of their stellar mass; measuring the clustering statistics of galaxies to constrain their halo mass distribution; and the incorporation of new constraints from weak gravitational lensing from Gurri et al. (2020, 2021).

Image credit: NASA