Potential PhD Topics
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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.
Dr. Emma Ryan-Weber (starts at CAS in February 2009)
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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. IMPORTANT: 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. Also, some staff already supervise several students and so may not list specific projects below; they may, however, still be willing to supervise you if they are listed above and you contact them to discuss possible projects.
Prof. Matthew Bailes:
Millisecond Pulsar Timing and Gravitational Wave Detection
Square Kilometre Array Supercomputing
Dr. David Barnes:
Advanced architectures for astrophysical supercomputing
Challenges in Astronomy Visualisation
Dr. Darren Croton:
Supercomputer models of the formation and evolution of galaxies
Supermassive active black holes: galaxy killers or innocent bystanders?
Dr. Chris Fluke:
Advanced architectures for astrophysical supercomputing
Challenges in Astronomy Visualisation
Prof. Duncan Forbes:
Probing Galaxy Groups and Measuring the Invisible
Using Keck to determine the origin of globular clusters
Prof. Karl Glazebrook:
First Light
Dr. Alister Graham:
Supermassive Black Holes
The Hubble Space Telescope Treasury Survey of the Coma cluster of galaxies
Dr. Jarrod Hurley:
Deciphering Galaxy Formation and Evolution through Globular Clusters
Evolution of Star Clusters
Galactic Novae Populations Across the Ages
Dr. Glen Mackie:
Dynamics of Rich Galaxy Clusters
Testing Formation models in the extreme - The Shapley Supercluster
Dr. Sarah Maddison:
From Dust to Planets
Observations of Grain Growth: the first step towards planet formation
Physical Chemistry of Protoplanetary Dust Formation
Dr. Michael Murphy:
Do the constants of Nature vary in spacetime?
Galaxies revealed by quasar absorption lines
Laser frequency combs: a new standard for astronomical spectra
The baryon and gas budgets for the Universe
Dr. Emma Ryan-Weber (starts at CAS February 2009):
The connection between Intergalactic Carbon and star formation at high redshift
The gas-rich cosmic web
Supervisors: Dr. David Barnes & Dr. Chris Fluke
The massively parallel graphics processing units (GPUs) that power today's graphics cards offer computing capabilities far beyond those of central processing units (CPUs). Accordingly, speed-ups of 100 times and more have been demonstrated for particular classes of astrophysics simulation codes running on graphics hardware compared to today's fastest CPUs. This project will commence with a review of the major astronomy algorithms for data simulation, reduction, analysis and visualisation, and a review of previous "ad hoc" efforts to port astronomy algorithms to GPUs. It will then entail the design and implementation of an (open source) software architecture for simplifying the deployment of appropriate astronomy algorithms on graphics card hardware, both single-node desktop and clustered GPU environments. The project may include the design and construction of a GPU cluster and the measurement and performance analysis of the various codes ported. Additional project options include the exploration of GPUs for computational steering, and/or the integration of visualisation with computation.
Supervisors: Dr. Chris Fluke & Dr. David Barnes
Astronomy is entering the era of petabyte computing, and with this comes an avalanche of new data products. Traditional analysis techniques may not be sufficient for astronomers to make the best use of the data sets that current and future instruments, such as the Square Kilometer Array and its pathfinders, will produce. Visualisation - computer generated representations of data - provides many exciting opportunities for astronomers to gain valuable new insight and understanding of their data, particular when used interactively in 3-d. This project will require the investigation, development and implementation of advanced 3-d visualisation techniques. Of specific interest are: the development of quantitative visualisation tools; enabling comparisons between computer simulations and radiotelescope data; and visualisation in the low signal-to-noise regime. The overall goal of this project is to provide innovative new visualisation software (and hardware) for astronomers to use, in order to maximise the scientific return from astronomical datasets.
Supervisor: Dr. Jarrod Hurley
Despite our in situ view of our Milky Way galaxy and our ability to observe its properties in great detail, we remain highly ignorant about its formation and assembly. The primary goal of this project is to take the archaeology of the Milky Way, and indeed galaxies in general, to a completely new level. This will be done by combining the most ancient and hence best fossil records of past galaxy history - globular star clusters - with the predictive power of state-of-the-art numerical simulations. Specifically, the project will combine galactic-scale simulations of star cluster formation with N-body simulations of star cluster evolution to develop the first non-simplistic picture of how a globular cluster system evolves with time and to determine how this impacts our interpretation of observed Galactic and extragalactic globular cluster systems. Results will include detailed predictions of the internal properties of star clusters - to be confronted with the latest observations - and an insight to the complex and dynamic merger processes that affect the galaxies of our Local Group, and beyond, even today. The grand aim of this project is to place the formation and evolution of globular clusters in its proper cosmological context.
Supervisor: Dr. Michael Murphy
The constants of Nature play a central role in our fundamental physical theories but these theories cannot predict the values of the constants we observe. Indeed, this is one hint that our theories may be incomplete and that a more fundamental, "grand unified theory" linking all physical interactions -- gravitational, electromagnetic and nuclear - might exist. Perhaps surprisingly, the absorption lines seen in the spectra of extremely distant quasars offer a fairly clean and precise probe of the values of some fundamental constants early in the Universe's history. Over the past 7 years, I have uncovered tentative -- and tantalising -- evidence that some constants may actually vary on 10 billion year time-scales. This PhD project aims to use new and existing quasar spectra to confirm or refute this evidence. Many different avenues may be followed in this project, but most are observational in nature with an emphasis on careful and repeatable data analysis. The student would carry out new observations on the world's largest telescopes (mostly the Very Large Telescope in Chile and Keck in Hawaii) and would analyse a large database of existing quasar spectra. There is also opportunity to use radio absorption spectra for similar studies. The student would collaborate with researchers in Sydney and in Cambridge (UK).
Supervisor: Dr. Glen Mackie
The 2dF Galaxy Redshift Survey and 6dF Galaxy Survey provide unique redshift data for rich clusters. Large numbers of redshifts enable the dynamical state of clusters to be determined accurately. The PhD student would investigate 1) the frequency and magnitude of peculiar velocities of Brightest Cluster Galaxies (BCGs) - as a guide to the dynamical state of the cluster, and 2) substructure (spatially and kinematically) by studying rich clusters with large numbers of galaxy redshifts. BCGs have previously thought to be located at the spatial and kinematical centre of rich clusters - recent results suggest that 30\% of all clusters have BCGs with significant peculiar velocities (BCG - cluster mean) suggesting that many nearby clusters are still dynamically young and evolving. Substructure can be identified optically (via redshifts and positions) and via the structure of hot gas (X-ray imaging). Quantifying substructure can reveal clues to the initial density perturbations out of which large scale structure (clusters, groups) form.
Supervisor: Dr. Jarrod Hurley
Here at Swinburne we have a range of N-body codes that model all facets of star cluster evolution. We also have teraflops computing power at our disposal via the Swinburne supercomputer and access to GRAPE and GPU special-purpose machines. This software and hardware combination means we can produce direct and realistic models of star clusters, including the possibility of direct modelling of Galactic globular clusters for the first time. As such this is a very exciting time for the field of star cluster simulation and a variety of associated projects are available. These include: the destruction of open clusters in our Galaxy; the formation of exotic stars via dynamical interactions in star clusters; the morphology of planetary systems in star clusters; stellar nucleosynthesis feedback in star clusters; the effect of dynamical evolution on the appearance of globular clusters; and intermediate-mass black holes in globular clusters. Plus numerous other possibilities - please get in touch if you have an idea not listed here.
Supervisors: Prof. Karl Glazebrook & Dr. Paul Stoddart (Applied Optics)
A key problem in cosmology is finding the epoch in time when the first structures in the Universe collapsed to form the first stars. The UV from these stars ionized the neutral hydrogen in the universe left over from the Big Bang, a process called 'reionization'. Current observations have pushed this epoch back to z > 7.
Accessing this epoch required deep NIR observations because all the emission from candidate objects is redshifted out of the optical region. Such observations are difficult because of the bright airglow from the night sky at these wavelengths. At Swinburne we are developing a new technology photonic filter which if successful could suppress this emission and make existing telescopes 10-20x more sensitive. Another technological advance is the advent of MCAO (Multi-Conjugate Adaptive Optics) which could allow for deep NIR imaging over wide fields with a spatial resolution better than HST.
Part of this PhD project will be to work on the design, development and testing of this filter. The other part will be to carry out deep near-IR observations (possibly using this filter) to detect galaxy poplulations beyond z > 7 using the classical 'Lyman Break technique'.
Supervisor: Dr. Sarah Maddison
With over three hundred newly discovered extra-solar planets, it is becoming very important to study the planet formation process. There is an ongoing project at Swinburne to study the earliest stages of the process in which micron size dust particles aggregate together to form metre size boulders that form the base material for planets. The PhD student will work on the theoretical aspects of the problem, using and modifying our 3D, dust+gas hydrodynamics code, and run simulations on the Swinburne supercomputer. Sarah is currently collaborating with groups in France on this project and the new student will become involved with these collaborations.
Supervisor: Dr. Jarrod Hurley
Cataclysmic variables (CVs) are binary stars in which the cannibalistic accretion of hydrogen-rich material from a red dwarf companion onto a white dwarf (WD) leads to periodic eruptions on the WD surface known as novae. These outbursts are incredibly energetic and make novae visible in galaxies outside of our own. Currently there is a significant and, so far, unsettled debate in the literature concerning the correlation between nova rate and Hubble type of galaxy. Traditionally it was thought that brighter, faster novae, powered by massive WDs, should more frequently appear in spiral galaxies (with young populations). Conversely, elliptical galaxies (with little or no recent star formation) are not expected to exhibit many luminous novae because the CV population will be dominated by low-mass WDs with low surface gravities. However, recent observations of many bright novae in the old elliptical galaxy M87 contradicts this point of view.
The goal of this project is to provide a more realistic set of nova population models than has hitherto been produced and to do this for a range of galaxy types. The PhD student would be responsible for interfacing the latest detailed models of nova outbursts (provided by collaborators at Tel Aviv University) with a binary evolution code. The student would then use this code to create artificial CV/novae populations for all galaxy types, `observe' these populations and make a detailed comparison with the M87 (and future) observations.
Supervisor: Dr. Michael Murphy
As the light from distant quasars travels through the Universe on its way to Earth, it occasionally passes through the outskirts of a galaxy. By identifying the absorption lines in quasar spectra that they cause, we can detect galaxies which may otherwise be too distant and faint to see with direct imaging. This is a potentially huge advantage of so-called "absorption selection". But there's a catch: the link between the absorption line properties and the galaxy properties is still unclear and so we must first study a sample of absorption-selected galaxies which are not so faint and distant as to be directly imaged to establish this relationship. Unfortunately, it's difficult to see even bright galaxies in the glare of the background quasars and most attempts at this have failed. However, with the Very Large Telescope in Chile (VLT) we have recently studied some details of some special classes of absorption-selected galaxies. We now aim to obtain Hubble Space Telescope observations to further characterise these galaxies. Large, ground-based telescopes like the VLT and Keck (Hawaii) will also be used to find more distant, and possibly more representative, galaxies. This project is observational in nature. There is opportunity for collaboration with groups based in Cambridge (UK), California (USA) and Victoria (Canada).
Supervisor: Dr. Michael Murphy
The 2005 Nobel Prize in Physics was awarded for the invention and application of the new laser frequency comb (LFC) technology. As the name suggests, LFCs provide a series of equally spaced "emission lines" which cover a very broad range of wavelengths. I am working with the European Southern Observatory (ESO) on building a LFC system that might be used to provide an ultra-precise wavelength standard for spectrographs on the Very Large Telescope in Chile and even on the planned European Extremely Large Telescope. But to understand how precisely we can really calibrate a spectrograph, sophisticated models must be constructed which allow us to simulate LFC spectra and how they are recorded with digital detectors like CCDs. This project mainly involves computational modelling and data analysis but it may also involve testing a LFC at the Anglo Australian Telescope in collaboration with the Centre for Atom Optics and Ultrafast Spectroscopy at Swinburne. The student would also collaborate with ESO to produce computer models of their planned LFC system, an effort which has just begun in Trieste (Italy).
Supervisors: Prof. Matthew Bailes, Dr. Willem van Straten & Dr. Ramesh Bhat.
Swinburne is part of a collaboration with the CSIRO's Australia Telescope National Facility to attempt to make the first detection of gravitational waves using an array of millisecond pulsars. This project involves using an 8 Gb/s baseband recorder and a supercomputing cluster to observe ~20 millisecond pulsars at the Parkes radio telescope and search for gravitational waves.
Supervisor: Dr. Sarah Maddison
With over three hundred newly discovered extra-solar planets, it is becoming very important to study the planet formation process. There is an ongoing project at Swinburne to study the earliest stages of the process in which micron size dust particles aggregate together to form metre size boulders that form the base material for planets. The PhD student will work on the observational aspects of the problem. Using the Australia Telescope Compact Array, the student will conduct millimeter and centimeter surveys of southern star forming regions to determine grain growth signatures in protoplanetary disks. This survey will be complimented by infrared studies to determine correlations between grain growth in different regions of the disk. Sarah is currently collaborating with groups in the Netherlands and the USA on this project and the new student will become involved with these collaborations.
Supervisor: Dr. Sarah Maddison
Condensation of dust grains in a cooling protoplanetary disk is an important first step in the building of planets. The chemistry of these grains have been studied through infrared observations and many of the main mineralogical aspects of dust in protoplanetary disks have been established. In this project the basic physical chemical aspects of these processes will be established through the use of computational thermodynamics via Gibbs energy minimisation. The technique has been successfully applied to many complex high temperature systems in the field of materials science and the knowledge from these studies will be applied to protoplanetary dust. Calculations will be performed to establish the chemical equilibrium for a number of complex systems and the effect of temperature, pressure, overall composition and choice of activity models will be used to calculate the equilibrium using existing software and databases. These models will be used to understand the composition of extrasolar planets and meteorites in our own Solar System.
Supervisor: Prof. Duncan Forbes
Most galaxies are found in groups, yet they are poorly studied relative to clusters. Using wide field spectrographs (eg AAOmega on the AAT and DEIMOS on the Keck Telescope) we can obtain stellar population properties and kinematics for a large sample of group galaxies. This will allow us to create a new volume and magnitude complete census of group galaxies. We aim to identify the mechanism for pre-processing in groups and to measure the dark matter halo mass from the kinematics of group dwarf galaxies and globular clusters. Isolated galaxies and fossil groups will form an interesting control sample. This observational project involves collaborators in the UK and California.
Supervisors: Prof. Matthew Bailes, Dr. Ramesh Bhat & Dr. Willem van Straten.
The next radio telescopes are being designed to observe at unparalleled sensitivity using monstrous aggregate bandwidths (several-100s of Terabits/s). This project involves taking the strawman specifications of the SKA and designing supercomputer solutions to the massive data processing problems they pose in the areas of transits, pulsars and radio bursts. Prototype supercomputers will be placed at the sites of Australian telescopes to do early science. A collaborative project with the GMRT will test algorithms and study giant pulses from neutron stars. GPUs and other add-in board solutions will be trialled.
Supervisor: Dr. Darren Croton
Using state-of-the art simulation and modelling techniques we will build entire universes from the ground up. This will begin with the evolution of dark matter and dark energy through N-body simulations of the evolving cosmic web, and be coupled with the phenomenology and physics of galaxy formation using analytic and semi-analytic methodologies.
The project has two primary aims: 1) We will develop a new model of galaxy formation that better reproduces the multi-wavelength properties of galaxies across ~10 billion years of evolution. This model will be compared with observations from the radio to optical to x-ray wavelengths. 2) We will construct mock catalogues and lightcones from the model galaxies/dark matter halos and use these to interpret the results from modern large-scale galaxy surveys (e.g. 2dFGRS and SDSS locally, DEEP2 and WiggleZ at z~1). We will also make predictions for upcoming "next generation" surveys, such as the Dark Energy Survey (DES), and data taken with the Large Synoptic Space Telescope (LSST) and Square Kilometre Array (SKA), amongst others.
I anticipate a number of published papers will result from this project, as well as the potential for collaboration with teams in Australia, Europe and the US. The student will be encouraged to present his/her results at at least one national/international conference each year.
Supervisor: Dr. Darren Croton
Active galactic nuclei (AGN) represent a unique population of objects in the Universe that encapsulate many otherwise diverse areas of physics. These include extreme environments of gravity (black holes), sub-to-kiloparsec-scale dynamics (black hole two and three body interactions and host galaxy mergers or secular triggers of black hole activity), sub-to-kiloparsec-scale hydrodynamics (gas infall, accretion disks, and AGN winds or jets), and their use as cosmological probes of the evolving large-scale cosmic web.
Black hole and galaxy growth are clearly linked, and there is a need to understand their common phenomenology in greater detail. This project will use the Swinburne supercomputer to develop detailed semi-analytic models of black hole formation and AGN activity to study their impact on galaxy evolution. In particular, there is strong evidence that AGN are the cause of the observed death of massive galaxies. How and when does this happen? What are the possible triggers, and are there unique observational signatures to discern one from the other. What multi-wavelength observations can be leveraged? Does black hole formation regulate bulge formation, or vice versa?
I anticipate a number of published papers will result from this project, as well as the potential for collaboration with researchers in Europe and the US. The student will be encouraged to present his/her results at at least one national/international conference each year. This project can be linked with parts of the previous project, "Supercomputer models of the formation and evolution of galaxies", as the students interests lead them.
Supervisor: Dr. Alister Graham
It has recently been recognised that "supermassive black holes", with masses one million to one billion times more massive than our Sun, reside at the heart of most galaxies (even those without an `active galactic nucleus'). Curiously, they appear to consistently represent 0.1 percent of the host galaxy's mass. Better understanding the connection between a galaxy's global stellar distribution and its central stellar density is expected to yield valuable insights into this phenomenon. This can be achieved through the careful analysis of Hubble Space Telescope images at optical and near-infrared wavelengths. Moreover, such high-resolution images actually allow one to measure the galactic damage caused by these cosmic wrecking balls. This will be achieved by carefully studying the images of some 50 galaxies with already measured supermassive black hole masses.
Supervisor: Dr. Glen Mackie
The Shapley Supercluster (SSC) is the most massive concentration of galaxies in the local universe. Recent redshift surveys have elucidated the distribution of bright galaxies in the core and outskirts of the SSC. The close vicinity of the SSC and it's large overdensity of galaxies offers a unique perspective into galaxy evolution at the very extreme of space densities. In general star formation appears to be quenched or suppressed for recently accreted galaxies. The PhD student would try to answer many remaining questions concerning the linkages between galaxy evolution and cluster environment. eg. Does the initial impact with the hot intracluster medium (ICM) cause an initial starburst then rather abrupt star formation cessation? Current observational plans include deep imaging of the SSC to explore the evolutionary status of low luminosity galaxies in conjunction with 6dF Galaxy Survey redshifts, the structure of the hot X-ray emitting gas and expanding on previous radio continuum studies. Current hierarchical models predict clear trends for elliptical galaxies in such environments and we intend to extend current observational vs. theoretical comparisons to below L* galaxies.
Supervisor: Dr. Michael Murphy
As the Universe evolves, gas is turned into stars and then, when the stars explode, the baryons are liberated into gas again. But through this recycling of interstellar material, we expect that the amount of neutral hydrogen available for star-formation should decrease as the Universe evolves. Tracking this depletion of neutral gas is one of the fundamental observational pointers for theories of galaxy formation. Most of the neutral gas in the early Universe resided in so-called "damped Lyman-alpha" systems (DLAs) -- gas clouds identified in quasar spectra by their strong (damped) neutral hydrogen Lyman-alpha absorption line. But now most gas resides in stars and, assuming that DLAs really do trace the formation of stars, it is hypothesised that the number and hydrogen content of DLAs should therefore have decreased over the past 5 billion years. This PhD project aims to find evidence of this: if it's found then it will help constrain theories of galaxy formation; if it isn't found then it will profoundly impact our understanding of the link between DLAs and star formation throughout the Universe. This is an observational project: we have begun an extensive survey for DLAs aimed at finding evidence for evolution in the DLA population. Observing time on the Shane 3-m telescope at Lick Observatory (California) is already secured and we are seeking time on larger telescopes like the 4-m William Herschel Telescope (La Palma, Spain), the Multiple Mirror Telescope (Arizona) and 10-m Keck Telescope (Hawaii). This is part of a collaboration with researchers in the UK and USA.
Supervisor: Dr. Emma Ryan-Weber
Perform a double blind experiment to measure the star formation rate of galaxies in fields that have been searched for Intergalactic Carbon. The star formation rates will be measured by the strength of Lyman-alpha emission through a narrowband filter. One of the major challenges of observing in the near-IR is discrete atmospheric emission due to OH. This study will take advantage of a fortunate co-incidence. Clean spectral windows exist between the OH lines at 0.8 and 1 microns, corresponding to triply ionized Carbon and Lyman-alpha, respectively, both at redshift 5.7. The project will address the question of whether there is a one-to-one correspondence between the generation of stars and the presence of intergalactic Carbon at this redshift.
The first set of data for this project has already been taken using the FORS2 on the VLT. Thus, the student could get going quickly on this project. Further observations would be required, possibly using Keck.
Supervisor: Dr. Emma Ryan-Weber
The ASKAP (Australian Square Kilometre Array Pathfinder, to be commissioned in 2010) will detect the 21-cm emission line of a million gas-rich galaxies between redshifts 0 and 0.2. The location of these gas-rich galaxies will be cross-correlated with Lyman-alpha features and other elements seen in absorption in the Intergalactic Medium (IGM). The different atomic species will be used to select a variety of temperature regimes in the IGM. The large volume of the ASKAP survey means that existing absorption line data will be able to be used immediately for this project. This study will identify large-scale structures in the Universe and reveal how gas of different phases and temperatures is accreted from the IGM onto galaxies.
This project would start off with theoretical calculations, using N-body simulations of gas and galaxies to make predictions. Any observations would depend on progress of ASKAP.
Supervisor: Dr. Alister Graham
The HST survey of the Coma galaxy cluster (http://astronomy.swin.edu.au/coma) is one of only two prestigious Cycle 15 (2006/7) Treasury Programs. It involves more than 40 research astronomers from eleven nations. It is the first survey of a nearby rich cluster using Hubble's Advanced Camera for Surveys. While the core of the Coma cluster is the densest galaxy environment in the local universe, the cluster as a whole harbors regions of widely varying galaxy densities. As such it allows one to study "environmental" influences on the physical properties of galaxies. There is opportunity for a PhD research project to study the central structure of these galaxies, where nuclear star clusters and black holes reside.
Supervisor: Prof. Duncan Forbes
Perhaps the key problem in globular cluster research today is understanding the origin of the two subpopulations. Although much has been learned from imaging, progress on this issue requires information that can only be gained from spectroscopy. Spectra give metallicity, abundance, age and kinematic properties. Such properties can be used to distinguish between the competing globular cluster formation models. We have excellent access to the world's largest telescope (Keck) which is necessary to obtain the required spectra. This project involves collaborators in California.