Potential PhD Topics
Below are listed those CAS staff who are currently looking for PhD students. Note that this does not mean they will always have specific projects listed in the next section of this page. Often it's best to talk to the supervisor first and, upon discussing your interests and skills with them, a project may emerge.
The following list outlines particular PhD projects currently on offer. Contact the staff member(s) listed for more information. Note that, due to the nature of research, this list constantly changes; potential PhD candidates are encouraged to contact the relevant staff member(s) as soon as possible. Other projects, not listed here, may be possible; contact the staff member above whom you feel is most suited to your ideas and areas of interest.
Prof. Matthew Bailes
- The Radio Universe at 1000 frames per second - Burst Discovery
- The Radio Universe at 1000 frames per second - Instrumentation
- The Radio Universe at 1000 frames per second - Burst Origins
A.Prof Chris Blake
- No projects offered at this time
Dr. Barbara Catinella
- No projects offered at this time
Prof. Warrick Couch
- No projects offered at this time
Dr. Jeff Cooke
Prof. Darren Croton
A.Prof. Chris Fluke
- No projects offered at this time
Prof. Duncan Forbes
Prof. Karl Glazebrook
Prof. Alister Graham
Prof. Jarrod Hurley
- No projects offered at this time
Dr. Glenn Kacprzak
A.Prof. Virginia Kilborn
Dr. Glen Mackie
Prof. Sarah Maddison
- Testing planetesimal collision models with debris disk observations
- A Dynamical Search for Habitable Worlds and Solar System Analogues
Prof. Jeremy Mould
- Hydrodynamic models of AGN circumnuclear disks
- Linking the stellar and interstellar properties of galaxies
Prof. Michael Murphy
A. Prof. Emma Ryan-Weber
- No projects offered at this time
Dr. Willem van Straten
- The Highest Precision Pulsar Timing
- Next-generation Instrumentation for Radio Pulsar Astronomy
- Interstellar holography using graphics processing units
Supervisor: Prof. Alister Graham, Aust. Govt. Future Fellow
Ultraviolet image of the Andromeda Galaxy taken
with NASA's Galaxy Evolution Explorer.
Image credit: NASA/JPL-Caltech
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. A feeling for the type of research done with Prof. Graham can be seen in his Press Releases.
One specific PhD project on offer will involve a search for the descendants of the massive, compact galaxies known to exist in the high-redshift, i.e. young, Universe but reportedly now missing today
Supervisor: Dr. Willem van Straten
High-precision pulsar timing with future telescopes such as the Square Kilometre Array will be ultimately limited by natural phenomena such as multi-path propagation in the turbulent interstellar medium and the impulsive noise that is intrinsic to the pulsar signal. Although techniques have been developed to mitigate some of these effects, modern pulsar instruments at the world's premiere observatories do not record the statistical information required to apply these methods on a regular basis. For this project, high-performance digital signal processing software will be developed for multi-processor architectures (such as general-purpose graphics processing units and field-programmable gate arrays) and demonstrated using pulsar data recorded at the Parkes Observatory. The new technology will enable a wide variety of experiments, ranging from studies of the pulsar emission mechanism to improving the sensitivity of pulsar timing arrays; the candidate will have the opportunity to pursue these topics in collaboration with an international team of experts. This research will contribute directly to the design of the pulsar timing processor for the SKA and equip the candidate with the expertise required to fully exploit the largest radio telescope ever to be built. The candidate will have access to state-of-the-art supercomputing facilities at Swinburne and advanced digital instrumentation at the Parkes Observatory. A strong background in the fundamentals of digital signal processing and experience with the C++ programming language would be highly beneficial. The applicant should also have some direct experience or a keen interest in learning to use the CUDA and/or OpenCL parallel computing platforms and programming models.
Supervisor: Prof. Sarah Maddison
7 mm image of the Fomalhaut debris disk made with ATCA.
The disk centre (blue star) is offset from the central
(yellow) star, in agreement with HST observations,
possibility due to the eccentric planet Fomalhaut b. From Ricci et al. (2012).
Planets are formed through the collisions of asteroid-like bodies in the early stages of planetary systems. But collisions between these bodies can also be disruptive and generate a swarm of dust fragments. The dust in debris disks is thought to be produced by collisions between km-sized planetesimals (comets and asteroids) leftovers of the planetary formation process. Since we cannot detect planetesimals, sub-mm and mm observations of the cold dust in debris disk is the only way to study these unseen bodies. Thermal dust emission in the sub-mm and mm wavebands can be used to study the size distribution of dust grains, which in turn can be used to distinguish between different collisional models. In this project, the student will join an international term conducting a survey of debris disks with the Australia Telescope Compact Array and other sub-mm and mm interferometers to study their intrinsic properties and test predictions of collisional models of planetesimals.
Wide-field radio surveys at high time resolution have been impossible to conduct because of their insanely high data rates and computational challenges. In this novel project we will transform Australia's largest radio telescope, the Molonglo 18,000 square metre telescope near Canberra into a wide-field (12 square degree) camera that images the radio sky at millisecond timescales. To achieve this we will deploy 24 5-teraflop GPUs in a supercomputer that will process 22 Gigabytes of data every second to undertake the most sensitive search for radio bursts at cosmological distances. In this first project on this massive undertaking we are seeking a student to search for and decipher the radio bursts that will be discovered.
Swinburne's Green2 Supercomputer
Credit: Swinburne ITS
Wide-field radio surveys at high time resolution have been impossible to conduct because of their insanely high data rates and computational challenges. In this novel project we will transform Australia's largest radio telescope, the Molonglo 18,000 square metre telescope near Canberra into a wide-field (12 square degree) camera that images the radio sky at millisecond timescales. To achieve this we will deploy 24 5-teraflop GPUs in a supercomputer that will process 22 Gigabytes of data every second to undertake the most sensitive search for radio bursts at cosmological distances. In this second project, we are looking for someone to help commission this powerful instrument, preferably with strong computing skills.
Millisecond pulsars offer the ability to measure pulse arrival times to 100 nanosecond precision. At such precision one can hope to see the influence of supermassive black hole binaries on their arrival times and potentially make the first ever direct detection of gravitational waves. At Swinburne we are members of the Parkes pulsar timing array for gravitational wave detection, and lead the South African MeerKAT proposal with the same aim. This project seeks a careful student who can help us help us test the theory of General Relativity and search for gravitational waves.
Supervisor: A.Prof. Virginia Kilborn
We are becoming increasingly aware that the galaxy group environment plays an important role in the evolution of galaxies. Galaxy groups are the most common environment in the Universe (over 50% of galaxies live in groups), and the proximity of galaxies in groups, and their low velocity dispersions provide conditions conducive to galaxy interactions. Many of the properties of clusters (e.g. high early-type fractions, redder stellar populations) are often observed in the group environment. This project will take a detailed look at the star forming properties of galaxies in nearby groups, using observations of their neutral hydrogen content, and current star formation rates. The neutral hydrogen (HI) observations are taken from the HI Parkes All Sky Survey (HIPASS) with high-resolution follow-up observations from the Australia Telescope Compact Array (ATCA) and the Jansky Very Large Array (VLA). The star-forming properties of the galaxies will come from the Survey of Ionization in Neutral Gas Galaxies (SINGG).
The SINGG survey was an H-alpha follow-up program, examining the star forming properties of HIPASS galaxies. Around 400 galaxies were observed in the Survey. Most of the galaxies observed were found to correspond with individual star forming galaxies - however, in about 5% of the cases there are four or more H-alpha emitting galaxies at the position of the HIPASS source. The HIPASS observations have very poor resolution so we do not know the HI content of the individual SINGG galaxies. To overcome this problem, we have performed high-resolution HI imaging with the ATCA - these data will allow us to distinguish the HI content of the individual galaxies. Since HI typically exists in a disk extending out beyond the optically bright portion of galaxies, it often shows signs of tidal disturbance and interaction. This the HI in these fields may give a better indication of how the galaxies in these groups are interacting. The student will assist in the observations, data reduction and analysis of the HI data. It is envisioned that the PhD student will lead this project and extend the data to other wavelength domains. This project will be co-supervised by Prof. Gerhardt Meurer (University of Western Australia).
Supervisor: Dr. Glen Mackie
The morphology-density relation for dwarf galaxies as displayed in the Local Group of galaxies suggests that dwarf irregular (dIrr) galaxies evolve into dwarf spheroidals (dSph), possibly due to the influence of massive galaxies. Although how thin, cold gas disks evolve into gas-poor, pressure supported spheroids is presently unclear. There does appear to be a 'transitional' type of dwarf galaxy (dTrans) that shares characteristics of dSphs and dIrrs. Recent surface photometry showing "outside-in" disk growth in dIrrs suggestive of stellar feedback regulation still has to be reconciled with HST colour magnitude diagrams (CMD) observed sustained starbursts that rule out such "self-quenching". The role of external processes associated with high mass galaxies may be overemphasised if the morphology-density relation is driven via (secular) evolutionary change.
The aim of this work is to examine deep wide-field imagery of dwarf galaxies to derive observed global quantities such as CMDs (nuclear and at large radii) and disk scale lengths via surface brightness profile fitting and to search for faint-light asymmetries or tidal tails. Some of the questions to be asked in this project include:
Are dIrrs in a process of rapid transformation? Do dIrrs may have different disk growth scenarios than more luminous spirals? Why are some dSphs found at large distances from luminous galaxies?
Supervisor: Prof. Duncan Forbes
A wide-field image of NGC 1407 and NGC 1400 in the
Eridanus group taken with the Subaru 8m telescope. The
image shows a large number of globular clusters in the
halo of NGC 1407.
The halos of elliptical galaxies have been poorly probed to date and yet they contain the vast bulk of a galaxy's dark matter. Using telescopes such as the Keck 10m and Subaru 8m located in Hawaii, and the Hubble Space Telescope, this project will obtain new dynamical and chemical information for nearby ellipticals. Galaxy and globular cluster data will be used to constrain the dark matter content of the host galaxy and to better understand galaxy formation processes. Skills in imaging and spectroscopy with large telescopes will be acquired. The project is likely to involve collaboration with colleagues based in California.
Supervisors: Prof. Karl Glazebrook & Danail Obreschkow (ICRAR/UWA), Roberto Abraham (Toronto)
One of the oldest and most fundamental observations about galaxies is they spin. Rotation drives the majestic spiral structures but also the properties of elliptical galaxies. Surprisingly the angular momentum distribution of galaxies has never been mapped systematically, unlike their mass and size, and neither is it consistently incorporated in to models. However simple physical arguments (Obreschkow & Glazebrook 2014) really do strongly imply angular momentum is critical to understanding the large scale diversity of galaxy structure and the Australian SAMI survey is leading the world to gather the first large scale survey of galaxy spin. The aim of this PhD is to take and analyse SAMI data as well as targeted follow-up data from the Keck telescopes and other high-redshift samples to carry out the first complete census of how angular momentum drives galaxy formation. Data will be compared with new theoretical models being constructed incorporating these new physical ideas as an underlying basis. This PhD offers the opportunity to have a major impact on our basic understanding of galaxies.
Supervisor: Dr. Jeff Cooke
The Hubble Extreme Deep Field. Deep images like this
reveal the colors and morphology of galaxies in the early
Universe. The Lyman alpha feature in the spectra of
these galaxies may provide the clue to resolving several
key problems in galaxy formation and evolution.
(Credit: NASA, ESA, and the HUDF09 team)
The Lyman alpha (Lya) atomic transition is typically the strongest feature in the spectra of high redshift galaxies but is perhaps the most complex and the least understood. Nevertheless, this single feature exhibits a strong relationship with a multitude of intrinsic and, surprisingly, extrinsic galaxy properties. Intrinsically, Lya correlates with the strength of interstellar metal absorption lines, dust content/reddening/colour, and strength of galactic outflows. In addition, Lya correlates with galaxy morphology and, recently suggested by our work, galaxy kinematics. Extrinsically, we have uncovered a strong relationship between Lya and the large-scale environment - whether or not host galaxies reside in group/cluster environments (overdensities) or in group outskirts and in the field. On small-scales, we have found a relationship between Lya and galaxy pair separation which is likely caused by mergers/interactions. Finally, recent work is revealing a relationship between Lya and the fraction of escaping highly-energetic ionizing photons (Lyman continuum photons) from galaxies that are likely the main contributor to the reionisation of the Universe.
The project involves the acquisition, reduction, and analysis of imaging and spectroscopic data from the Keck telescopes and potentially other 8m-class telescopes, combined with previously acquired data from various other major telescopes worldwide. The project focuses on galaxies at redshifts z ~ 2 - 6 (or lookback times of 10 - 12.5 billion years when the Universe was 10 - 25% its current age) when galaxies were in an important formative stage. You will synthesise these data to quantify and better understand the link between Lya and the large number of seemingly unrelated properties (listed above) in an effort to help resolve several outstanding problems in galaxy formation and evolution.
Supervisors: Prof. Sarah Maddison & Dr Jonti Horner (UNSW)
Mean dynamical lifetimes of test "Earths" in the
habitable zone of HD204313 as a function of their
semi-major axis and eccentricity.
(Credit: Thilliez et al. 2014)
In recent years, a significant number of multiple planet systems have been discovered around nearby stars, and dynamical methods have become increasingly important in the discovery and categorisation of exoplanets. The search for exoplanets is now moving into a new era, where astronomers seek to quantify the number of Solar System analogues around other stars. Such system will feature potentially habitable rocky planets like the Earth, and massive Jupiter-like planets moving on decades-long orbits. But where should we look? How do we decide which exoplanetary systems are the most promising locations for potentially Earth-like planets? And which systems are most likely to host as-yet undetected Jupiter-like planets? Using a new theoretical framework, this project will use numerical techniques to search for dynamically stable planet candidates in the habitable zones of known multiple planet systems to provide answers to these questions. The results of this research will produce a list of promising targets for planet search programs as they search for planetary systems like our own.
Supervisor: Dr. Glenn Kacprzak
Cool gas (blue) 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.
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, galaxy halos are the key astrophysical laboratories harboring the detailed physics of how galactic feedback governs galaxy evolution. The student will have the choice between a theoretically and an observationally based project.
Project 1: 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 onobtainable using any other method of observation. Here, the student will examine how feedback processes effect their host galaxies using using Hubble Space Telescope data and will be involved in the acquisition, reduction, and analysis of data from the Keck telescopes.
Project 2: Disentangling these feedback processes has not been successful using observations of galaxies alone; a complete understanding of galaxy evolution requires detailed simulations of galaxies and their gaseous halos. Using both observations of galaxies and simulated galaxies, the student will aim to develop an understanding of "galactic feedback" and its influence on galaxy evolution. The student will become part of an international team that will examine the properties of gaseous halos and feedback processes with state-of-the-art simulations.
Supervisor: Prof. Jeremy Mould
Spatially resolved spectra will be compared with models of gas disk structures around AGNs following the approach of Wada, Papadopoulos and Spaans (2009). These are high-resolution numerical simulations of the interstellar medium in a central R < 32 pc region around a supermassive black hole (1.3 × 10^7 M⊙ ) at a galactic centre. Three-dimensional hydrodynamic modelling of the ISM with the nuclear starburst includes tracking of the formation of molecular hydrogen out of the neutral hydrogen phase as a function of the evolving ambient ISM conditions with a spatial resolution of 0.125 pc. The gas forms an inhomogeneous disk, whose scale height becomes larger in the outer region. Molecular hydrogen forms a thin nuclear disk in the inner <5 pc, which is surrounded by molecular clouds swelled up toward height above the plane < ∼ 10 pc. The velocity field of the disk is highly turbulent in the thick disk region, whose velocity dispersion is ≈20 km/s on average. A range of viewing angles is computed. Input parameters are the rotation curve, which is strongly constrained by Keck adaptive optics and ALMA observations, the ultra-violet radiation field from the AGN and the supernova rate in the star forming gas. On the 0.125 pc grid four equations are solved simultaneously: continuity, conservation of momentum and energy and the Poisson equation. The model outputs density, temperature and kinematic 3D maps, which can be visualized from any observer position. These can be directly compared with our observations. Residuals from fitting the models to the velocity resolved observations of the excited gas and molecular maps. will yield key information such as inflow and outflow rates and modes.
The PhD will start with the theoretical / numerical modelling of the Circinus galaxy: the student will begin with radiative transfer simulations of the warped central disc in order to explain some features of interferometric observations and then move on to hydrodynamical simulations of the central gas distribution. A second object will be selected from our observations in Hawaii and Chile. Both sub projects would build on work done by Swinburne research fellow Marc Schartmann.
Radiative transfer simulations and hydro-modelling is a good basis for a career in numerical astrophysics.
Supercomputer simulations of the co-evolution of dark matter, galaxies and black holes allow astronomers to test competing ideas about galactic evolution and cosmology, which can then be compared against observations. However, the natural data format of such simulations is very different to what a telescope collects. Hence, much work is needed to fairly bring the two together to do science.
At Swinburne we have built an online virtual laboratory, the Theoretical Astrophysical Observatory (TAO), which provides a key link in this chain. TAO houses queryable data from multiple cosmological dark matter supercomputer simulations and galaxy formation models. It has the ability to: construct observer light cones from the simulated data cube; and generate complete spectral energy distributions for model galaxies to provide multi-wavelength coverage.
The main objective of this project is to build a new interactive telescope simulator within the TAO framework. This inter-disciplinary research project will require the student to: (1) understand how different telescope facilities and instruments work, including the Hubble Space Telescope, KECK telescopes in Hawaii, and the Australian Square Kilometer Array Pathfinder radio telescope; (2) simulate the instrument and other internal and external effects important for telescope imaging and signal processing; and (3) develop the software infrastructure required to mimic such effects on theoretical data generated from the TAO cosmological simulations and galaxy formation models. The final result will be an online virtual telescope facility that becomes part of TAO and is available for use by the international astronomy community. This project is designed for students with strong computer programming skills.
Supervisor: Prof. Jeremy Mould & Elisabete da Cunha
Knowing the stellar population and interstellar medium content (i.e. dust and gas) of galaxies is crucial to understanding galaxy evolution. Information about these components of galaxies is encoded in the light they emit at different wavelengths.
The goal of this thesis is to measure physical properties (stellar ages, masses, star formation rates, stellar and gas-phase metallicity, dust attenuation) of galaxies from their observed optical spectra. GAMA http://www.gama-survey.org is creating an extraordinary multi-wavelength photometric and spectroscopic dataset. By virtue of its unrivaled combination of area, spectroscopic depth, high spatial resolution and broad wavelength coverage the GAMA dataset is uniquely capable of advancing galaxy studies. The upcoming TAIPAN spectroscopic survey of galaxies will not only allow us to map the local Universe with unprecedented detail, but will also allow us to study the emission by stellar populations and ionized gas in galaxies. The stellar continuum and absorption features in the optical spectra of galaxies contain information about the ages, metallicities and masses of stellar populations in the galaxies. Emission lines in the spectra arise mainly from photo-ionization of interstellar gas by the ultraviolet radiation produced by young stars, and hence trace the current star formation rate. Observed emission line fluxes also depend on the gas metallicity, ionization state, and the amount of dust in the interstellar medium.
In this thesis the student will implement a new version of the MAGPHYS spectral energy distribution code (da Cunha et al. 2008) which will include a self-consistent computation of the emission by stellar populations, nebular emission, and dust attenuation and emission. The first step will be the development of a Bayesian spectral fitting code to compare the models with optical spectra at similar spectral resolution while optimally exploring the model parameter space. The method will be then tested on optical spectra from the GAMA survey. The results obtained with this spectral fitting technique will be compared with the results given by routinely-used indicators of the star formation rate, metallicity and dust content that use monochromatic fluxes and/or a few emission lines. Finally, the student will apply this spectral fitting method to samples of low-redshift galaxies from the GAMA and TAIPAN surveys in order to investigate links between their stellar population and interstellar medium properties.
Animation of the reionization of helium gas in the
Universe: As the UV light from powerful quasars ionizes
helium in the intergalactic medium, the gas heats up.
But when all the helium is ionized, the quasar light
can no longer heat the gas; it passes straight through and
the gas begins to cool down as the Universe expands
As the Universe expanded and cooled after the Big Bang, the first stars and galaxies formed from “pristine gas” – predominantly hydrogen and helium left over from the Universe’s first few minutes. When those first stars exploded as supernovae, they dispersed the heavy metals synthesised during their short lives and spectacular deaths into the intergalactic medium. These first stars probably also "reionised" much of the Universe’s hydrogen gas with their ultraviolet light, leaving neutral gas only in large, diffuse, enriched filaments laced with proto-galaxies. Thus, after just 1 billion of its current 14 billion year history, the gas surrounding early galaxies likely comprised metal-enriched filaments and outflowing gas, and perhaps vestiges of the pristine gas, relics orphaned from the nurseries of the first stars.
This project aims to verify and quantify this picture of early galaxies, their surroundings, and the intergalactic medium. Several different research directions are possible, though most will involve using quasars as bright, background light sources to probe and understand the gas seen in absorption. Some example topics include:
- Identifying extremely metal-poor and possibly pristine gas pockets in the early Universe;
- Weighing the universe by searching for new examples of deuterium absorption;
- Tracking the evolution of the intergalactic medium's thermal state; and
- Studying how galaxies are fueled by new gas from their surroundings.
Opportunities exist for collaboration with researchers in California (USA), Cambridge (UK) and Heidelberg (Germany), depending on the topic. It is envisaged that this project will be observational in nature, but students interested in the theoretical and simulation aspects of these topics are also encouraged to apply.
Supervisor: Dr. Willem van Straten
The dynamic spectrum (bottom panel) shows pulsar flux
density varying as a function of time and frequency due
to interstellar scintillation. The dynamic filter
magnitude (top panel) was derived using cyclic spectroscopy and holographic phase retrieval techniques. Image Credit: Walker, Demorest & van Straten (2013).
The Astrophysical Journal, v. 779, p. 99.
Inhomogeneity in the density of free electrons in the interstellar medium (ISM) causes the index of refraction to vary on spatial scales that span many orders of magnitude (from the size of the Earth to the spiral arms of the Galaxy). These spatial irregularities, long thought to be driven by turbulence in the ISM, produce both refractive and diffractive aberration and scattering effects that are observed as spectral and temporal variations of pulsar flux density (known as scintillation, shown in Figure) and broadening of pulses due to multi-path propagation delays (known as scattering).
For this project, cyclic spectroscopy and holographic phase retrieval techniques will be used to determine the instantaneous impulse response function of the interstellar medium and map out the structure of scattering material along the lines of sight to pulsars in our stellar neighbourhood. The project will require development and testing of high-performance digital signal processing software for multi-processor architectures (such as general-purpose graphics processing units and field-programmable gate arrays) followed by experimental demonstration using pulsar data recorded at the Parkes Observatory. The new technology will enable a wide variety of experiments, ranging from studies of turbulence in the Galactic magnetic field to improving the sensitivity of pulsar timing arrays; the candidate will have the opportunity to pursue these topics in collaboration with an international team of experts.
This research will contribute directly to the design of the pulsar timing processor for the low-frequency component of the SKA and equip the candidate with the expertise required to fully exploit the largest radio telescope ever to be built. The candidate will have access to state-of-the-art supercomputing facilities at Swinburne and advanced digital instrumentation at the Parkes Observatory. A strong background in the fundamentals of digital signal processing and experience with the C++ programming language would be highly beneficial. The applicant should also have some direct experience or a keen interest in learning to use the CUDA and/or OpenCL parallel computing platforms and programming models.