Phd and Honours - Honours projects

PhD projects are programs which target significant new bodies of research over a 3-4 year timescale. As an astronomy PhD student you will be involved in developing (with your supervisors) a program of research designed to attack some set of key questions. You will have to write observing proposals, take data, analyse it and prepare it for publication, as well as writing up your results in thesis form. The AAO can offer co-supervision of students in PhD projects together with a University-based supervisor at your home institution.

The following are a few potential projects for PhD students. Astronomy is a subject in which developments move rapidly - so the hot topics by the time a project starts could have changed. All projects are worked out by discussion between you and your prospective supervisor, so treat this list as a source of ideas and a starting point. Members of staff may have other projects waiting in the wings. Students who are interested in subject areas not covered below are encouraged to contact relevant AAO astronomers directly. Students who are interested in projects in astronomical instrumentation should contact Andrew Sheinis, the AAO's Head of Instrumentation.

  • The Rise of the Jellyfish: Galaxies caught in the act of environmentally driven transformation

Supervisor: Matt Owers

In this project, the student will study the enigmatic "jellyfish galaxies'" and their surrounding environment. Jellyfish galaxies are found in massive clusters of galaxies and exhibit one-sided trails of extremely blue knots and filaments. These knots and filaments are interpreted as the manifestation of hot, young stars formed in-situ within gas which has been stripped from the parent galaxy, indicating the jellyfish are in the process of being transformed by the environment. Observing galaxies "caught in the act'' of being strongly transformed by the environment will lead to a better understanding of the dominant physical mechanisms at play. 
The student will use integral field spectroscopy (from the new KOALA instrument on the 3.9m Anglo-Australian Telescope and the WiFeS instrument on the 2.3m telescope at Siding Spring Observatory) to investigate the impact of this gas stripping on the star forming properties of the galaxy, and also to investigate the properties of the blue knots and filaments in the tails. Furthermore, the student will use the combination of X-ray information (provided by the Chandra and XMM-newton satellites), which traces the hot intra-cluster medium, and multi-object spectroscopy (from the AAOmega instrument on the AAT), which traces the dynamics of the cluster through galaxy velocities, to obtain a detailed understanding of the environmental conditions required for the formation of a jellyfish galaxy. 
The student will gain valuable skills in collecting, processing and analysing data taken with some of the world's premier instruments and observatories while collaborating with researchers from Australia and around the world.
  • Major cluster mergers as drivers of galaxy transformation and evolution

Supervisor: Matt Owers

The most extreme form of structure formation in the Universe occurs when two massive clusters of galaxies merge to form a single entity. This violent event vigorously rearranges the environment of the residing galaxies and simulations suggest that this process may result in an enhancement in the mechanisms which drive the transformation of spiral galaxies into elliptical galaxies. Furthermore, recent observations of merging clusters at radio wavelengths have hinted at an increase in the number of galaxies which have undergone a recent episode of intense star formation activity -- an excellent signature of a galaxy in the throes of rapid evolution. However, the increase in the population of these galaxies is not ubiquitous amongst merging clusters and the emerging hypothesis is that the details of the cluster merger are key factors in understanding the ifs, hows and whys of cluster merger induced galaxy transformation.
This project will initially involve the analysis of Giant Metrewave Radio Telescope observations of three merging clusters of galaxies for which deep Chandra X-ray observations and comprehensive multi-object optical spectroscopy (MOS) exist. The Chandra and MOS data have been used to place tight constraints on the dynamical history of the mergers and the radio data can now be exploited to test the relationship between the merger parameters and the radio galaxy population in merging clusters. In combination with the study of the optical spectral properties the galaxies in these clusters, the radio data offers an excellent opportunity to undertake a detailed investigation of the effects of cluster mergers on the resident galaxies. There is ample opportunity to extend the project to include a larger sample of clusters.
During the project, the candidate will acquire skills in reducing and analysing radio data -- a much desired skill given Australia's involvement in future surveys to be undertaken with the Australian Square Kilometre Array Pathfinder radio telescope. The candidate will also be provided with opportunities to form collaborations with colleagues based around Australia and overseas.
  • Galaxy And Mass Assembly: The projected phase space distribution of group members by spectral type

Supervisor: Matt Owers

Groups of galaxies are the most common galaxy environments and are the building blocks of the massive clusters of galaxies. It is therefore important to understand the properties of galaxies in groups, abd how this environment impacts a galaxy's properties. Simple local density or group-centric distance measurements which are typically used to define galaxy environment do not utilise all of the information at hand. In this project, it is proposed that the kinematics of group galaxies be incorporated by using the peculiar velocity as a function of projected group-centric-radius, or the projected phase-space (PPS), as a measure of galaxy environment. Simulations show that the position of a "galaxy" in PPS can be used to approximately distinguish galaxies which are virialised, infalling, or have passed pericentric passage but are at large clustercentric distance. Depending on how the passage through a group impacts the star-forming properties of a galaxy, these populations should display different spectral types. Recent work on massive SDSS clusters by Mahajan et al. (2011) has demonstrated that galaxy spectral properties correlate strongly with the position on the PPS, indicating that star formation may be completely quenched after the first passage through a cluster. 
In this project the high-fidelity GAMA group catalogue will be used to explore the impact of the group environment on the starforming and AGN properties of member galaxies. This will be achieved by investigating the positions in stacked PPS diagrams for different spectral types in groups with masses in the range 10^13-10^14.5 M_solar. Spectra will be analysed to enable the identification of normal quiescent and starforming galaxies, as well as transition/evolving/active galaxies (starburst, recently quenched and AGNs). To assess the importance of galaxy mass, the positions of different spectral types on the PPS will be compared across a range of stellar masses, with the deep GAMA data allowing to probe the regime where environmental effects dominate (i.e. to M*~10^9 for z<0.15). This work will provide insights into the environmental mechanism responsible for quenching in the group regime.
During the project, the student will work with members of the GAMA consortium -- an Australian-led international team ( The student will develop skills in working with the large, multi-wavelength data sets provided by the GAMA survey, thereby placing them in good stead to exploit future large-scale astronomical surveys.
  • The angular momentum of massive galaxies

Supervisor: Sarah Brough

Our current model of the formation of galaxies suggests that they grow gradually over time through mergers with other galaxies.  The most massive galaxies observed today have therefore gone through many such mergers. The initial galaxies are thought to start off as rotating systems and with each merger the galaxy loses more and more rotation until they are barely rotating at all.  However, small studies of some of the most massive galaxies, Brightest Cluster Galaxies (BCGs), find that some are still rotating, in stark contradiction to our current picture.

Until recently, there were only small numbers of observations of these massive galaxies.  The ground-breaking multi-object integral-field SAMI galaxy survey now means that there are observations of hundreds of these galaxies.  This project will therefore use SAMI observations to resolve this conundrum and understand why some massive galaxies are still
rotating.  Integral field observations are the future of astronomy so this project will be an important grounding in a crucial new technique.

  • The unbound stars of massive galaxies

Supervisor: Sarah Brough

One of the pressing, unanswered questions in astronomy is why the most massive galaxies in the Universe are not observed to have grown in mass as much as theoretical models suggest that they should have. A possible solution is that galaxies merging with the most massive galaxies may actually be destroyed into clouds of unbound stars in the process. This would also explain the origin of diffuse, stellar haloes observed around some of the most massive galaxies: Brightest Cluster Galaxies (BCGs). BCGs are massive elliptical galaxies found at the centres of groups and
clusters of galaxies.

This project would utilise data from the multi-wavelength imaging and spectroscopic Galaxy And Mass Assembly (GAMA) survey to select the BCGs and undertake initial surface brightness analyses before obtaining new deeper imaging from world-class international telescopes to measure the mass of diffuse light and its origin for the first time.  This project will provide key skills in data mining, image analysis and obtaining astronomical observations.

  • Outer kinematics and chemistry of nearby galaxies

Supervisor: Caroline Foster

The outskirts of galaxies retain signs of galaxy assembly that can last for billions of years and are otherwise invisible in the galaxy centres. Recent literature have shown that several galaxies exhibit interesting and dramatic kinematic transitions beyond the usually probed inner regions. This transition to a kinematically distinct halo (KDH) is predicted theoretically although it has only recently been confirmed observationally. How common this feature is, its possible association with stellar population transitions or as a function of Hubble types remain to be explored using a sizeable samples.

Using world-class optical telescopes in Hawaii and Chile, the "SLUGGS" (near infrared) and "Dragons" (visible) projects are obtaining large scale reconstructed kinematic and chemical abundance maps for a sizeable sample of nearby galaxies. These two surveys are highly complementary, covering different spectral wavelengths and galaxy types, thereby enabling a deeper understanding of systematics.

This project offers the possibility of early involvement in the new Dragons survey, the use of data from world-class observatories and of a recently developed data reduction technique (Norris et al. 2008; Proctor et al. 2009) to push the galactocentric boundary. The selected student will acquire invaluable spectral and kinematical analysis skills that are easily portable to popular IFU studies. The Dragons survey is an international collaboration between scientists in Australia, Canada, Chile, USA and The Netherlands, hereby offering a connection to further worldwide opportunities.