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Descriptions of Current PhD Research

Ellert.van.der Velden - Utilizing cosmological simulations to model the growth of galaxies and their role in ionizing the universe

Understanding the events during the early universe is still one of the greatest cosmological mysteries that we are facing.
In order to try to understand these events and how they led to the universe we know today, we usually create semi-analytic models. Using semi-analytic models allows us to investigate what happened during the early universe by using the physical knowledge and observations we have today. However, a shared problem with all models is that they usually have a large number of parameters, which combined make up a decently large parameter space.
Only a very small part of this parameter space can potentially create a model realization that would be interesting to look at. One of the most commonly proposed solutions is the usage of MCMC methods, but although they are quite reliable, they can be incredibly slow if evaluating the model takes some time.
For that reason, I am developing an algorithm (based on the Bower et al. 2010 paper) that instead tries to construct an approximation of the model (Meraxes) by only using polynomial terms. Such a model is much faster to evaluate than the model it is based on and allows one to search for interesting parts of parameter space much quicker.

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 the most prominent feature in the spectra of distant galaxies 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.

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.

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.

Cherie Day - Pinpointing the origin of fast radio bursts

The ultimate goal of my contribution to the UTMOST-2D project is to localise Fast Radio Bursts to their host galaxies using the Molonglo Radio Telescope and to use this information not only to determine the types of objects responsible for these short but highly energetic bursts but also as a means of mapping the universe. To accomplish this, new developments in the instrument must be made in order to increase its capabilities. Thus, a substantial part of my project will be to design and construct the signal processing chain for and commission the second arm of the interferometer. With this first-hand knowledge of the instrument, an optimised detection pipeline for the data can be developed as well as the imaging and analysis tools needed to provide burst positions and well-calibrated position uncertainties.

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.

Chandrashekar Murugeshan - Understanding Galaxy Evolution with Next Generation Radio Telescopes

Neutral hydrogen (HI) studies are important for understanding galaxy evolution since HI is the primary ingredient essential for star formation. HI morphology can tell us a lot about a galaxy’s environment and whether it has likely to have undergone any interaction or merger, and as such the project will also involve parametrising the HI morphologies of galaxies. One of the main goals of my PhD is to study the HI distribution as a function of stellar mass. A trend in the distribution of HI and stellar mass based on the different morphological and optical types would then lead to a distinction in the evolutionary stages of galaxies, thus paving ways to understanding their evolution. I will also examine if environmental effects influence the HI content in galaxies.

Daniel Berke - Are the fundamental constants of nature very truly constant?

Debatri Chattopadhyay - Binary millisecond pulsars and black hole binaries in star clusters

I work on simulating star clusters, looking for black hole and millisecond pulsar binaries in them, their evolution and mergers - which generates gravitational waves. Albert Einstein's General Theory of Relativity predicted almost a century ago, that accelerating masses send ripples through the fabric of space-time, that propagates like a wave with the velocity of light, famously called "Gravitational Waves". The technological advancement has enabled us to detect these waves created by gravitational interactions and mergers of heavy two body systems, and the 2017 Nobel prize in Physics was awarded to for the detection of it.
As a part of OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, I look for interesting binary systems and their subsequent merger, which may emit detectable gravitational waves. Star clusters are dense environments which make them the birthplaces and collision hubs for these heavy mass binary systems. These higher mass binaries produce gravitational waves that LIGO and VIRGO can detect and thus, they are interesting members to study in the extreme, dense environment of globular clusters, where dynamical events and collisions are a common occurrence. I also plan to theoretically compute binary evolution and subsequent mergers of black holes and neutron stars by population synthesis. Simulations now run on the Green II: gSTAR and SwinSTAR supercomputer, and in future, will be running on the new OzSTAR supercomputer, currently under installation at Swinburne. Starting my PhD in this new era of astrophysics is really exciting for me, and the future of gravitational waves seems to be limitless. Guiding me through this quest of knowledge are my supervisors Dr. Jarrod Hurley and Dr. Matthew Bailes.

Dian Triani - Modelling the SED evolution of galaxies throughout cosmic time

Modelling of galaxy formation is a process that is tightly coupled with the dark matter simulation. Based on this, on my PhD thesis, I will be supervised by Prof. Darren Croton and Dr. Manodeep Sinha to make predictions for the SED of galaxies throughout its formation timeline.

The modelling of each SED includes modelling of the complex processes of galaxy evolution, such as gas accretion, star formation, supernova feedback, and dust physics. We will try to understand and place these processes into a consistent sequence and create the SED that comes from each. The synthetic SED then will be used to interpret observational results, focusing on the infrared light which is typically observed in the distant universe. This new SED model will enable us to create predictions of galaxy evolution, as probed through its SED, across the entire history of the universe.

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.

Geoffrey Bryan - Dynamical processing and jet entrainment of dust around young stellar objects

The presence of refractory crystalline minerals such as forsterite (Mg2SiO4) in cometary dust and in the relatively un-processed interiors of some kinds of meteorites poses a challenge to the conventional theory of the development of the Solar System. These objects form in relatively cool regions of the accretion disc surrounding young stars, yet crystalline forsterite and its analogues requires processing at high temperature, in the inner part of the accretion disk to form. My PhD project will investigate whether the combination of star-burst eruptions of young stars and dust entraining jet flows (possibly induced by wound-up magnetic fields) is a suitable mechanism for explaining the chemical properties observed in the meteorite population, and satellite sample return missions as well as the infrared observations of young stellar objects.

I have a BSc with Honours in Theoretical Physics and a Masters degree in Engineering Science (thesis title: "On the analysis of axis-symmetric eddy currents" both from Monash University and a Masters degree in Business and Information Technology from the University of Melbourne. I worked in the Australian government's research organisation CSIRO for more than twenty years in diverse roles including: fluid dynamics researcher, IT manager, research administrator and executive officer.

Grace Lawrence -

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.

James Esdaile -

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.

Leonie Chevalier - The Study of Nearby Galaxies, their Evolutionary Histories and Dark Matter Content

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.

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.

Nandini Sahu - Prediction of Gravitational Waves from Galaxy Bulges

Poojan Agrawal - A new paradigm of globular cluster formation with multiple stellar populations

My work is to construct a new theoretical model for globular cluster formation
with multiple stellar populations.
Globular clusters are the most massive and oldest class of star cluster
populations; they host a variety of stars at different stages of their life including
some of the exotic ones like blue stragglers, low-mass X-ray binaries and
millisecond pulsars. A good part of our understanding of stellar evolution
comes from them. However, recent observational studies have discovered that
most of the GCs consist of different stellar populations with different chemical
abundances; GCs are no longer a simple stellar system with a single age and a
single metallicity, as previously thought. This new discovery has revolutionized
the research field and demands a more realistic model for the formation and
dynamical evolution of GCs to be developed.
This is important not just from the point of view of understanding stellar
properties like chemical abundances, stellar kinematics and radial structure but
also for constraining binary population in globular clusters which are important
sources of Gravitational waves. In particular, a better understanding of the early
evolution of clusters (when BHs are forming) is important for theoretical
predictions of gravitational wave signals from compact binaries.
Hence, my task involves modifying the N-body code called NBODY6 for
modelling properties of stars in a cluster and using the results to account for the
observations and thereby, making new predictions.

Pol Gurri Perez - How to measure what cannot be seen: the dark matter that surrounds galaxies.

The main goal of my PhD is to perform studies of projected galaxy pairs in which some appreciable degree of weak gravitational lensing is taking place. Through bespoke analysis of each individual galaxy-galaxy lensing system, the aim of the PhD is to make direct measurements of the masses and shapes of dark matter halos around individual galaxies.

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 doesn’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 quasar’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, etc…

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.

Robert Dzudzar - The evolution of gas-rich galaxies in the group environment

This PhD project is under the supervision of Assoc. Prof. Virginia Kilborn, Prof. Gerhardt Meurer and Dr. Sarah Sweet.

During my PhD project I will analyse the star forming properties of galaxies in nearby groups, using observations of their HI content, and current star formation rates. The 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). The star-forming properties of the galaxies will come from the Survey of Ionization in Neutral Gas Galaxies (SINGG).

Using the high-resolution HI imaging combined with the star formation and stellar properties of the galaxies, I will:

* Determine the star formation efficiency of galaxies in the group environment;

* Investigate the existence of tidal dwarf galaxies in groups;

* Study gas stripping and accretion in the group environment;

* Search for tidal features in the HI gas that indicate interactions are affecting the member galaxies.

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.

Stephanie Bernard -

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.

Tim Dykes -

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.

Vivek Gupta - Mapping the Universe with FRBs

Fast Radio Bursts (FRBs) are very mysterious astrophysical radio signals which most probably are originating outside our own galaxy. FRBs have perplexed astronomers for more than a decade now. To be able to unravel their mystery, we need to detect and localize the source of more and more FRBs. New telescopes are being developed across the globe and old ones are being renovated to achieve this goal.

I will be working towards developing observation strategies and detection algorithms which can be implemented across various observatories in order to maximise their ability to detect and localize FRBs. Further, I shall be analyzing the characteristics of detected FRB signals and trying to work out the physical processes causing them; and the properties of the Intergalactic Medium by decoupling the effect it has on the FRB signal as it travels through it.

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 “Telescope Generic” 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

Nearly a decade ago, a new class of radio transients emerged, dubbed Fast Radio Bursts (FRBs), holding the potential to provide additional insight to the workings of the ephemeral universe. FRBs are millisecond wide, intense bursts of radio emission, that together share a very exciting feature: the observed mean electron density along the line of sight to their sources substantially exceeds the maximum expected from our own Galaxy. In other words, models suggest that FRB emitters reside at cosmological distances, attributing the excess in electrons seen to the intergalactic medium. As such, FRBs are thought to be promising cosmological probes.

Although it is estimated that an FRB strikes earth every few minutes from a random direction on the sky, detecting them is not an easy task as our telescopes have limited fields-of-view and/or sensitivities. Moreover, the very radio spectrum in which they are discovered is increasingly polluted by our own communication technologies. All this, coupled with the fact that new generation telescopes will swamp researchers with data, means that gone are the days when astronomers had to inspect their data by eye. Machine learning provides new methods of data analysis without the need of explicit programming.

The aim of my Ph.D. thesis is threefold: to develop novel tools that will aid in the acceleration of Fast Radio Burst discoveries, to gather a large sample of these bursts for statistical analysis and to understand the completeness of previous/ongoing FRB surveys, such as the ones conducted by the Parkes radio telescope.

Building a real-time, machine learning-based, FRB detection pipeline to operate on the newly refurbished Molonglo Observatory Synthesis Telescope (UTMOST) was among the first projects completed during the initial stages of my Ph.D. A real time detection using UTMOST will allow a rapid multi-wavelength followup of an event, and a better localisation on sky. The pipeline aided in the discovery of the third FRB detected by the interferometer to date, and promises the detection of many more.