Descriptions of Current PhD Research
Garry Foran - The Lya project: Understanding galaxy formation and evolution by exploring relationships between the observed properties and environments of galaxies over cosmic time.
Galaxy formation and evolution is one of the major unresolved problems in astrophysics. With the aim of understanding the physical processes behind the appearance and environment of galaxies, I use spectroscopy to study the intrinsic and extrinsic properties of galaxies in the early universe.
Specifically, I am exploring relationships between the Lyman-alpha atomic transition of hydrogen ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Å“ the most prominent feature in the spectra of distant galaxies ÃƒÂ¢Ã¢â€šÂ¬Ã¢â‚¬Å“ and internal and external properties such as galactic kinematics and the so-called morphology-density relation.
By investigating the above relationships for two galaxy populations that comprise the bulk of all distant galaxies, and by exploring these relationships over cosmic time, I am aiming to incorporate the understanding we gain into a consistent picture of galaxy evolution from 12 billion years ago to the present day.
Adebusola Bamidele Alabi - Unveiling the Dark Halos of Eliptical Galaxies
Globular clusters are fossil relics of early times in the Universe. Due to their age, compact nature, extended distribution and ubiquity, they are useful as probes in studies of formation and evolution of structures in the Universe. Using the combined power of wide-field photometry (Subaru telescope) and multi-object spectroscopy (Keck telescope), I'll be searching for substructure signatures in the globular cluster systems of the carefully chosen SLUGGS sample.
Alex Codoreanu - The nature of First Stars
I am working on understanding the absorption profiles observed in the spectra of quasars. Quasars are very bright objects which means that we can observe them from very far away, more than 13 billion years ago in fact or beyond redshift 5. As the light emitted by these bright objects traverses the Universe it passes between galaxies and interacts with the matter in the Inter Galactic Medium, IGM for short. This interaction creates absorption profiles that can tell us about the stars which have "polluted" the IGM.
By putting a lot of these observations together and by studying the relative strengths of different ionization states of Carbon, Oxygen, Silicon and other metals, I will better constrain the stellar population models and their number density in order to better understand the process of reionization of cosmic hydrogen.
Aditya Parthasarathy - High precision pulsar timing
Nature, more often than not, reveals a truly remarkable way of enabling us humans, to understand her. One of these magical revelations and a gift to astronomers, are Pulsars (which are highly magnetized, rapidly rotating neutron stars with beams of coherent emission from their magnetic dipoles! - how cool is that?).
"Space" and "Time" are a fundamental way of understanding this universe and measuring "time" precisely in interesting and extreme parts of the universe is key, to understanding the behavior of space. Pulsars are clocks that are distributed across the universe, that can be timed precisely to understand the nature of space in those regions. Such studies have enabled us to detect planetary companions around these stars, test theories of gravity, understand the interior structure of neutron stars and also the possibility of detecting gravitational radiation.
My research involves the timing of these marvellous rotating stars and studying their single pulses to mitigate noise and achieve better precision in timing. I will be working in commissioning the MeerKAT radio telescope in South Africa and the new wideband receiver at Parkes, both of which are great for the future of pulsar timing. I would also be involved with the Parkes Pulsar Timing Array (PPTA) team on projects related to pulsar timing and gravitational wave detection. Finally, I would be working on the pulsar timing programme and the automatic scheduling of the Molonglo Radio telescope, which would make it more awesome than it is already!
Supervising me in this already exciting PhD journey are Prof.Matthew Bailes and Dr. Willem van Straten. Along with them, there is an entire team of cool pulsar astronomers who are amazing to work with.
Adam Stevens - Simulating the Formation of the Most Massive Structures in the Universe
Unlike other scientists, astronomers do not have the luxury of running laboratory experiments. We can, however, design and trial theory through computer simulations. Finite processing speeds is a constant limitation on the detail of these simulations, leading to various methods attempting to balance resolution and size with computing time. The initial component of my PhD will be to measure gross properties of galaxies in massive cosmological hydrodynamic simulations as a function of time and compare these results with the more computationally efficient, but less detailed, semi-analytic models. Broader, long-term goals will be to utilise and develop these simulations to build on the theory of large-scale structure formation and galaxy evolution.
Bogdan Ciambur - Galaxy structure and intermediate-Mass black Holes
Bernard Meade - Coping with the data deluge: Combining remote visualisation and novel interaction techniques with ultra-high resolution displays to maximise the scientific returns of massive astronomy datasets
In my research I am looking at the challenges facing astronomy researchers in dealing with ever-increasing datasets. I am combining remote visualisation tools such as cloud computing with ultra-high resolution displays to improve research potential.
Caitlin Adams - Testing the cosmological model in the low-redshift Universe
Data from the low-redshift Universe can play a key role in testing cosmological models. Specifically, measurements of the peculiar velocities of galaxies can be used to probe gravitational physics on large scales. This allows tests of modified gravity models, which predict deviations from General Relativity, and may provide an alternative explanation for dark energy. The limited survey volume of low-redshift surveys leads to high sample variance, but it has been theorised that this can be mitigated by cancelling sample variance between the velocity and density fields of the survey. In this PhD, I will apply this theoretical approach to data from the 6 degree Field Galaxy Survey, with the aim to test modified gravity models.
Chris Curtin - Super-Luminous Supernovae - DB Covering the deaths of the first stars
I am part of the Survey Using DECam for Superluminous Supernovae (SUDSS). We are trying to create a large sample of superluminous supernovae for statistics and followup.
I use a technique which filters out all objects but Lyman break galaxies in order to filter my supernova detections to only those in the redshift range from 2-4. These are extremely distant supernovae by the technological standards of today.
At this large redshift, theory suggests that we will find an over abundance of the so called pair-instability supernova (PISN). These supernovae need to originate from stars which were very massive and very metal poor. These are precisely the conditions we expect to see at high redshift. The existence of this type of supernova remains in question, however there are candidates that have been observed in archival data.
PISNe, if confirmed, would constitute an excellent way to probe the very first population of stars, population III (pop3) stars. While we expect only a fraction of pop3 stars would explode as PISNe, these explosions would be more observable than core collapse supernovae, especially at high redshift, making such explosions most likely the first observable signature of pop3 stars. While it is unlikely that we will be able to observe a convincing example of a pop3 star at a redshift of less than 6, we are quickly approaching that threshold and will need to know what to look for when the time comes.
Colin Jacobs - Using machine learning to search for strong gravitational lenses in astronomical 'Big Data'
My project, under Prof. Karl Glazebrook and computer vision expert Dr Chris McCarthy from the School of Software and Electrical Engineering, is investigating the application of modern machine learning techniques to astronomical data. As new telescopes and surveys such as DES, LSST and the SKA get up and running they will generate staggering amounts of data. Mining such large imaging databases for their scientific potential is a complex task that will require sophisticated automation. For instance, while we know of several hundred examples of strong gravitational lenses, tens of thousands are likely to be hiding amongst the data collected by these surveys. For my PhD project I am looking at the particular problem of teaching a computer to automatically identify galaxy-galaxy lens candidates using convolutional neural networks. If successful, astronomers will be able to use those lenses to probe the nature and distribution of dark matter and the shape and history of our universe.
Dany Vohl - GPU-Accelerated Discovery in the Petascale Astronomy Era
I will research, implement, test and evaluate new GPU-based approaches to
visualisation, data analysis and data intensive research with the goal of accelerating discovery in the Petascale Astronomy Era
Elodie Thilliez - Searching for Hidden Planets
Debris disks are dusty circumstellar disks found around many main-sequence stars. Grain sizes in these disks range from micron (for the dust component) to meter (for planetesimals). Those disks are dynamical systems, where the dust evolves through collisions and fragmentation, thus continually replenishing the disk with new dust. Recent resolved debris disk images exhibit interesting radial and azimutal structures, such as gaps, rings and warps. Those configurations are likely to be the results of planetary companions shaping the disk by their gravitational influence. Using a N-body code, the main purpose of my PhD is to create numerical simulations of such systems and thus infer the presence of planetary systems to explain the current observations.
Fabian Jankowski - The radio Universe at 1000 rames per second
I hold a degree "Diplom-Physiker" from DESY and Humboldt-University, Berlin, Germany. I specialise in experimental particle physics and further in astroparticle physics. My previous work was in gamma-ray astronomy. I focused on the question of the origin of cosmic rays, mostly from a theoretical point of view. I modelled the non-thermal multi-wavelength emission of supernova remnants from radio to TeV energies and compared this to broad-band observational data.
In September 2013 I commenced my PhD at Swinburne University of Technology under the supervision of Prof. Matthew Bailes and Dr. Willem van Straten. My interest is in pulsar science and radio transients. I am mainly involved in re-commissioning the Molonglo radio telescope. As a first step I investigated the population of pulsars and radio bursts that would be observable with Molonglo. Since then I have implemented an automatic observing mode, took data nearly every night, worked on pulsar timing, built an analysis pipeline for the incoherent mode and helped debugging the instrument. I am also involved in and lead observation proposals for the Parkes telescope.
For up-to-date information please visit my website.
George Bekiaris - Unveiling Galaxies in 3D
We are poised on the brink of a revolution of our understanding of galaxies in the nearby Universe. New instruments being commissioned on telescopes will allow the first large surveys of the 3D properties of galaxies by measuring their internal structures and kinematics over large cosmological volumes. This is achieved with the technique of "Integral Field Spectroscopy" (IFS) - taking resolved spectra at every spatial point in a galaxy to make 3D data cubes. In particular this allows us to measure how galaxies move and rotate via the Doppler shift of their spectral lines. The aim of my PhD project is to develop the fundamental new software methods and tools which will be required to understand this fire hose of new data. The software will take advantage of new GPU technologies and massively parallel architectures.
Igor Andreoni - Super-Luminous Supernovae: Discovering the Deaths of the First Stars
My research interests include the detection and the science of transient events, along with 'multi-messenger' studies to search for electromagnetic counterparts to gravitational wave signals.
Transient sources appear in the sky, evolve, and finally fade away at all time-scales. Supernovae, for example, become bright (sometimes enough to rival the brightness of their own host galaxy) and then disappear within a few weeks, or a few months. However there are transient events that have very short durations that are relatively unexplored. For example, high-energy flashes called 'supernova shock breakouts' precede their optical emission (lasting only a few seconds), and mergers of neutron stars can produce explosions called 'kilonovae' (lasting only a few hours). Transients are therefore discovered over a wide range of time-scales and studied over the whole electromagnetic spectrum and beyond, as some catastrophic events emit a huge amount of energy in the form of gravitational waves. Gamma-ray bursts peak in the gamma rays, but their afterglow can be detected in the X-rays, ultraviolet, optical and at longer wavelengths, with some of them predicted to be gravitational waves sources. Finally, a new class of transients has been recently discovered in the radio called 'fast radio bursts'. These bursts last only a few milliseconds, less than a blink of your eye, but can be seen from across the Universe. Fast radio bursts, along with fast transients at all wavelengths, represent a challenging and unexplored world that we are now starting to unveil.
During my PhD I explore the fast (seconds to hours time-scale) dynamic Universe with coordinated, simultaneous observations in time-domain with radio, optical, UV, X-ray and gamma ray telescopes in the framework of the 'Deeper Wider Faster' project.
Isabel Rodriguez Herranz - Compact massive galaxy evolution, peanut-shaped bulges
Jacob Seiler - Reionization and Diffuse Cosmic Gas in the Universe
Understanding modern day structure depends critically on how well we can track the evolution of galaxies from small gravitational perturbations near the beginning of the Universe, through to the massive objects we currently observe. One important period in the evolution of the Universe is the Epoch of Reionization which marks the phase transition from a nearly homogenous Universe, to one that is highly structured. Probing this epoch presents an observational difficulty as the extreme distances prevents significant measurements from being made. My PhD will involve incorporating the physics behind the Epoch of Reionization into current models of galaxy formation. A further goal of my project will involve determining exactly how reionization proceeds; whether an 'inside-out' or more complex model model more accurately reproduces the observations we have.
Katharina Lutz - How do Galaxies Accrete Gas and Form Stars?
Galaxies host huge reservoirs of atomic hydrogen (HI). These HI clouds fuel smaller clouds of molecular hydrogen, which in turn form stars. When comparing the amount of gas that is transformed into stars with the total amount of gas available in galaxies, it is found that all available gas would be consumed within approximately 3 Billion years. This, however, is in contradiction to the average age of galaxies, which is approximately 10 Billion years. From that fact we can conclude that galaxies need to replenish their gas content to be able to keep on forming stars and by today it is common agreement that this is done via accretion. Nevertheless, the physical mechanisms behind accretion onto galaxies are not yet clear. In my PhD thesis I will observe the HI mass and velocity distribution of a sample of galaxies with exceptionally large HI content making use of the Australian Telescope Compact Array (ATCA) in order to search for clues of how accretion works.
Leonie Chevalier - The Study of Nearby Galaxies, their Evolutionary Histories and Dark Matter Content
Luz Angela Garcia - Intergalactic Metals at the conclusion of Reionization: theoretical
After the recombination epoch, all the Hydrogen in the Universe was neutral and the cosmic gas was filled of HI and other primordial elements. The hot plasma was essentially neutral and opaque (period commonly known as Dark Ages), but the formation and evolution of the first stars produced emission of ultraviolet photons, which ionized the Hydrogen, ending up with Reionization era. Despite the fact that the Universe was again transparent to be observed, the galaxy formation and enrichment of the ISM had proceeded, so there is a huge gap of the cosmic history that has been lost and must be studied by indirect observations in the sky.
One of best ways to study the early universe when Reionization occurred is using the QSO spectra. The Lyman absorption lines (and other metals) are the imprint of the absorbed incoming radiation from the quasar by the IGM and other structures.
QSOs are the brightest objects in the early Universe, therefore the study of their spectra is very important in Cosmology in order to understand the high redshift Universe.
In this scenario, the main goal of my research is to make theoretical predictions on how Reionization took place in the early Universe: was it an instantaneous (as a phase transition) or a continuous process? How did it happen? What was the topology of the the IGM sources during Reionization? The first question that the thesis will address is: how well is the fraction of neutral-to-ionized hydrogen represented by the fraction of low-to high ionisation metals? For instance, is there a tight relation of the fraction CII/CIV with HI/HII taking into account some physical conditions in the IGM?
Besides, the ionization potential of OI is similar to HI, hence, the ratio OI/OVI is expected to be a good proxy the neutral-to-ionized hydrogen ratio after Reionization?
These questions will be addressed by the use of hydrodynamical simulations with the SPH approach at redshift z~6 and will allow us to derive some constrains on the mass fraction of metals (OI, SiII, CIV, MgII, and FeII) with different ionizing UV backgrounds and compare the numerical results with observational measurements of metal absorption lines of QSOs spectrum.
Luca Rossi - The True Globular Cluster Mass Function Across the Hubble Sequence
Globular clusters are dense stellar systems that contain hundreds of thousands to millions of stars. They are found in large quantities in galaxies of all types. Indeed, they are the most ancient and best fossil records we have for probing the evolution history of galaxies. One important tool for such analysis is the globular cluster mass function (GCMF) of individual galaxies - essentially a census of the current globular cluster population of a galaxy. Complicating this census is that a globular cluster can be modified or even dissolved completely by the actions of the environment in which it resides - thus the present day GCMF will not reflect the true GCMF throughout the evolution history of the host galaxy. My PhD program aims to utilise numerical simulations of globular clusters evolving in a range of realistic galaxy environments to unearth the true GCMF as a function of host galaxy type.
The primary tool will be an N -body code called NBODY6 that is ideal for modelling globular cluster evolution in detail. Simulations with NBODY6 will be performed on the new Swinburne supercomputer (g2: gSTAR/swinSTAR) to take advantage of the speed-up offered by graphics processing unit (GPU) hardware.
Luis Torres - Testing the Cosmological Model using the Topology of large-scale Structure
The large-scale distribution of galaxies is a powerful probe of the composition of the Universe and gravitational physics. Standard studies of galaxy clustering from large surveys measure Ã¢â‚¬Å“2-point statisticsÃ¢â‚¬Â such as the correlation function or power spectrum. However, a great deal of additional cosmological information is encoded in the topology of the galaxy distribution, the characteristic network of clusters and voids that fills the Universe. This information is contained within the Fourier phases that are ignored in the standard analysis. My PhD project is oriented to utilize the latest galaxy datasets, such as the WiggleZ Survey, 6-degree Field Galaxy Survey and Baryon Oscillation Spectroscopic Survey, together with N-body simulations, to characterize the topology of large-scale structure.
The abundance and geometry of cosmic voids and superclusters, and correlations between the Fourier phases, will be used to test the cosmological model in new ways. We will explore optimal methods for filtering out the non-linear information that is difficult to model, such as density-field clipping and log-normal transformations. The result will be a series of cosmological tests to complement the standard approaches.
Matt Agnew - A Dynamical Search for Habitable Worlds and Solar System Analogue
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 a 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?
The core goal of my PhD is to use numerical techniques to search for dynamically stable planet candidates in the habitable zones of all known multiple planet systems.
Mark Durre - Active galactic nuclei: an examination of their physical environment and properties.
I am studying with Prof. Jeremy Mould, observing active galactic nuclei and their associated super-massive black holes, specifically looking at the dust and gas surrounding and obscuring the central engine.
Using near infrared integral field spectroscopy, the kinematics, distribution and other physical parameters of these features can be determined. We will use large telescopes with infra-red integral field spectroscopy with high spatial resolution, on samples of nearby radio source galaxies.
Mark Hutchison - Photoevaporation in dusty protoplanetary disks
Protostars are formed when giant molecular clouds of gas and dust gravitationally collapse, thereby converting gravitational potential energy into thermal energy. However, random motion of gas and dust particles, along with conservation of angular momentum, prevents all of the material from directly accreting onto the star. Instead, the leftover material settles into a geometrically thin, flared disk around the midplane of the newly formed star. While these disks are nearly ubiquitous around stars of a few million years (Myrs) in age, there is a dramatic decline in the number of observed disks for stars after about 7 Myrs, suggesting that disk dispersion occurs rapidly and almost simultaneously over a large range of radii. The relatively few transition disks that have been discovered further supports the idea of a quick dispersal of both gas and dust.
Photoevaporation is largely accepted as one of the mechanisms behind this rapid dispersal phase of the disk. Stellar UV and X-ray photons irradiate and heat a thin surface layer of the disk causing the gas to expand. In regions far enough from the central star, this expanding gas can escape the pull of gravity altogether and, thus, provides an effective means whereby gas and dust (via aerodynamic drag) can be removed simultaneously over large areas of the disk. Although simple photoevaporation models have been effective at reproducing certain key features observed in protoplanetary disks, there are still substantial uncertainties in the relative abundances and roles of different wavelengths throughout the entire process. Furthermore, photoevaporation has not yet been implemented alongside fully coupled gas and dust evolution models where both large and small dust-to-gas ratios coexist in the same disk.
The main focus of my Ph.D. will be using smoothed particle hydrodynamics to further explore the effect of dust dynamics on photoevaporative winds with the hope that our results will better constrain the uncertainties currently associated with photoevaporation models.
Paul Frederic Robert - Pristine Gas in the Early Universe
My main interests are Galaxy Formation and Evolution, and the Intergalactic Medium (IGM). The IGM is the gas between galaxies. It is supposed to be the principal reservoir of normal matter: baryons. Therefore, it plays a crucial part for the formation of the first stars and consequently the first galaxies. It is then very important to probe its properties. However, it doesnâ€™t emit much light. To detect it, we have to rely on the quasar absorption line technique. Quasars are very bright objects that can be seen even at a relatively large distance from us. They shine through the IGM and intervening gas interacts with their emitted light. That process will leave absorption patterns in the quasarâ€™s spectrum collected by a spectrograph. By studying these features, we can infer which elements compose the absorbing gas in the line of sight, physical properties such as velocity distribution, density, temperature, metallicity, ionization state, etcâ€¦
My project is oriented toward a particular class of absorbers: the Lyman limit systems (LLS). They are defined by a neutral hydrogen column density, N(HI), such that 17.2 < log(N(HI)/cm2) < 20.3. In the past five years, very metal-poor LLSs, i.e. with almost no metal lines, have been detected (metals here refer elements heavier than helium). The existence of such metal poor, or near-pristine, environments in the vicinity of the IGM is exciting as it could bring more information about the first stars (Pop III stars), and the gas cycle in early structure formation. Pop III stars supposedly appeared in metal-free gas clouds, and their death as supernovae polluted the IGM with metals. Near-pristine absorbers could be remnants of this primordial gas. My aims are to:
I. Identify more of these extremely low metallicity absorbers, either with existing data or future observations.
II. Find explanations for their origin.
Rebecca Allen - Detecting the Fain Remnants of Galaxy Formation
After the discovery of fossils we learned that ancient things existed on Earth long before us. Then, there was the thrill of the hunt as the fossil record became more complete with each new discovery. But where are the bones of galaxies? How can we distinguish the nearby elliptical giants from the compact ancestors? Using the Z-FOURGE survey I plan on compiling a photometric record of distant, compact red galaxies and compare their structures with galaxies of the present time. Specifically, are these distant red nuggets the progenitors of our massive neighbors and, if so, how did they grow and acquire their size? Addressing these questions and analyzing the properties of the inherent stellar populations can produce a more precise galactic fossil record.
Renee Spiewak - Searches for Millisecond Pulsars and Fast Radio Bursts
PhD Candidate Searching for Millisecond Pulsars - with more to come
Sabine Bellstedt - Unveiling the Dark Halos of Eliptical Galaxies
Early-type galaxies (consisting of elliptical and lenticular galaxies) have in recent years been understood to display a large range of kinematic features, despite how homogeneous these galaxies appear from their imaging alone. We attribute these variances in kinematic features to be due to the varying formation histories that individual galaxies have, and through a combination of observational analysis and theoretical studies, we can now begin to identify what kind of formation history an individual galaxy may have undergone based on their observable features.
Most such studies have focussed on high-mass early-type galaxies. My work looks at the lower-mass early-type galaxies, to understand whether their formation scenarios mirror those of the higher mass galaxies, or whether there are different mechanisms at play. I also utilise kinematic mass modelling techniques to determine the total mass distribution within these galaxies, to understand how a galaxy's formation affects it's matter distribution (both stellar and dark), and to identify theoretically predicted trends observationally in the low-mass parameter space.
Shivani Bhandari - The radio universe at 1,000 frames per second - instrumentation.Searching and Localisation of Sources of Dispersed Radio Emission
This project involves transforming Australia's largest radio telescope, Molonglo Radio Telescope, into wide-field camera capable of performing precision pulsar timing of multiple pulsars, radio sky mapping and searching the radio sky for fast radio bursts. The main goal is the commissioning of this large-scale project to achieve these cutting edge science goals.For this project, it will be necessary to cope with the hostile environment of Radio Astronomy.Main challenges involve detection and excision of radio frequency interference, phase the array to ultimately create tied array beams and radio maps using the output of the supercomputer. My science goals are related to the synthesis imaging using Molonglo, and also include the localisation of new pulsars that are being discovered at Parkes, large-scale structure in red-shifted HI.I am also part of the High Time Resolution Universe surveys (HITRUN) and Surveys for Pulsars and Extragalactic Radio Burst (SUPERB).
Sarah Hegarty - Accelerating and Enhancing Knowledge Discovery for the Petascale Astronomy Era
As astronomy enters a new era of petabyte-scale data, traditional approaches to visualisation and analysis will soon be inadequate for the astronomer's knowledge discovery needs. To address the need for new approaches, my PhD Project assesses traditional astronomical computing practices for the petascale age, and investigates the effectiveness of novel, emerging technologies for analysis and visualisation of large data sets.
Srdan Kotus - Do the fundamental constants of Nature vary in spacetime?
The main question in my work is whether the fundamental constants of nature are actually constant. Fundamental constants are numbers that are central to any physical theory, but those numbers cannot be calculated within those theories. We assume that these numbers are constants because, so far, we seem to find the same value whenever and wherever we try to measure them. The fine-structure constant is one of these numbers which characterizes the strength of electromagnetic force. There is currently some evidence that the fine-structure constant could vary in spacetime, which could be seen at very large distances.
In my PhD project we conduct an experiment in which we are looking at a cloud of gas between us and a background source of continuum light (quasar) through a spectrograph. When the light passes through gas clouds, only light at very specific colours (wavelengths) which corresponds to specific atoms/ions is absorbed. Through the spectrograph we see this as black stripes on a background rainbow. Among many things that we can infer from these stripes, we can see whether the distance between some of them is different compared to the same stripes measured in laboratory. If that is the case, which has been tentatively shown by my collaborators, than we can infer that the fine-structure constant in those clouds is slightly different from its value in the laboratory. Alternatively, we can check whether some systematic errors may be affecting the measurements.
My project is to look at new spectra taken from some of the largest optical telescopes in the world and see if there is some difference in fine-structure constant and also to search for systematic errors that can occur in these spectra.
Stephanie Pointon - Understanding the Relationship betwee Galaxies and their Gas
As much of half the baryonic mass of galaxies are found in galactic halos rather than stars and visible objects. This mass is in a gaseous form known as the circumgalactic medium. Currently, it is theorised that cold gas with low metallicity resupplies galaxies by spiralling in along the galactic plane. Galaxies, in turn, eject gas which has much higher metallicity and temperatures. Recent observations tend to support this theory. However, the theory has only been tested against a small number of galaxies.
The properties of the CGM are determined using the absorption lines found in quasar spectra. These absorption lines arise from the gas in the CGM absorbing the light from background quasars. Properties such as metallicity, temperature, column density and the kinematics can be calculated from the spectra. It is then possible to determine the behaviour of the CGM and the surrounding galaxies. Previous research has focused on lone galaxies. I will be expanding the survey of galaxies to include those in clusters.
Toby Brown - Revealing the gas cycles in galaxies
My principal research is in the area of multi-wavelength studies of nearby galaxies, aimed at understanding the connection between gas and stellar components, and their relation to the environment. In particular I make use of extragalactic HI surveys in order to study the open issues surrounding the observed properties and star formation potential of local galaxies.
I am working with current radio data from both the Arecibo Observatory and the Australian Telescope Compact Array (ATCA).
Themiya Nanayakkara - MOSFIRE spectroscopy of galaxies at Cosmic Noon
Using precise photometric redshift pre-selection from ZFOURGE and deep imaging
from Hubble Space Telescope in this PhD project an efficient study will be done
with MOSFIRE on galaxy populations across a range of cosmic environments (from Ã¯Â¬Âeld to rich cluster). Galaxy spectroscopy provides the fundamental redshift distance and cosmic environment measurements which underpin our understanding of cosmic evolution. It will allow us to measure the co-dependence of mass and star-formation via star-formation and metallicity diagnostics and measure galaxy halo kinematics via velocity dispersion and rotation measures. New imaging data from HST (the CANDELS survey) will provide high-resolution imaging to elucidate the physical structures (disks, bulges, star-forming clumps) and it's connection to the spectroscopic measures.
Uros Mestric - Characterising Lyman Continuum Galaxies
The details surrounding the end of the Epoch of Reionization is one the most topical questions in modern astrophysics. Less than 1 billion years after the Big Bang, the hydrogen gas in the Universe encountered a fundamental phase change and transitioned from a neutral to ionized state. The most likely source of the ionizing radiation behind this change is Lyman-continuum emission escaping from galaxies. The problem is that we only have a fragmented understanding of what types of galaxies provide the most ionizing flux at any point in the history of the Universe. Galaxies at redshifts of 3 to 4 are in a 'sweet spot' for detecting their Lyman-continuum radiation and can inform us of the contribution by galaxies at earlier times. The aim of this PhD project is to measure the escaping flux from galaxies at redshifts of 3 to 4 and to characterise their properties (such as luminosities, morphologies, and emission lines) for the first time.
Vincent Morello - Machine Learning for Radio-Astronomy
Vivek Venkatraman Krishnan - Advanced Software Correlation Techniques for Multi-Element Arrays
My PhD Thesis mainly focuses on developing new instrumentation techniques for time domain astronomy. I will specifically focus on new â€œTelescope Genericâ€ ways to detect and excise radio frequency interference which is crucial at the dawn of the SKA era. I will also develop efficient algorithms for detection, analysis and timing of pulsars and other fast radio transients at real time harnessing the advancements in computer science such as massively parallel computing architectures and big data management. I will primarily use the Molonglo Observatory Synthesis Telescope (UTMOST) for my thesis which is currently being refurbished to have a new backend. Hence, I will be helping with several aspects of the refurbishment during the initial part of my PhD. Apart from UTMOST, I will also use the MEERKAT radio telescope and the CSIRO Parkes radio telescope for developing and testing my techniques. Once the techniques are developed, I will use them to do high precision pulsar timing and transient searching with the telescopes mentioned above.
Wael Farah - Machine Learning for Radio Transient Searches