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Colloquia Series

For more information on colloquia at the Centre for Astrophysics and Supercomputing please contact Dr. Joel Pfeffer or Dr. Barbara Mazzilli Ciraulo ()

Swinburne Virtual Reality Theatre
AR Building, Room 104
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2023 Colloquia

Thursday Dec 14, 10:30
Tomoko Suzuk (IPMU Tokyo)
Colloquium: Rest-frame NIR structures and gas properties of massive star-forming galaxies at z ~ 1.5
It is suggested that there is a connection between the presence of a dense core, or bulge, at the center of galaxies and the star-formation suppression. Whereas the bulge formation is a pivotal aspect of a galaxy’s evolutionary history, it remains unclear when and how it happens. In this study, we investigate the stellar structures of massive star-forming galaxies (logMstar/Msun >~ 11) at z ~ 1.5, which are expected to be in the morphological transformation phase and quench soon. Our targets were spectroscopically confirmed with Hα, and their molecular gas masses were measured from previous sub-mm observations with ALMA. Molecular gas properties, such as gas mass fraction and gas depletion timescale, are key to understanding the physical mechanisms driving the bulge formation and growth. We investigate the stellar structures of our massive star-forming galaxies with JWST/NIRCam data from COSMOS-Web and characterize the properties of their bulge components without being affected by dust extinction. We then investigate how these structural properties are related to the molecular gas properties. I would like to show our first results for half of our target galaxies. If I have time, I would also like to introduce galaxy surveys planned with upcoming/future wide-field instruments on the Subaru Telescope.
Monday Dec 11, 10:30
Pavan Uttarkar (Chris Blake)
Student Review: Pavan Uttarkar MCR
Friday Dec 8, 10:30
Student Review: Monse's DTR
Tuesday Dec 5, 10:30
Lydia Haacke ()
Student Review: Lydia Haacke CoC
Lydia's CoC review. Panel Chair Karl
Thursday Nov 30, 10:30
Tony Travouillon (ANU)
Colloquium: Cryoscope: Ultra-wide IR survey from Antarctica
Studying the dynamic sky is about to be revolutionised by the LSST survey. An infrared counterpart is however needed to pierce through self-occulting events and the dustier centre of the galaxy. The Cryoscope telescope is a project that proposes to use the Antarctic continent and its unique atmospheric characteristics to perform a dynamic survey with a volumetric speed on par with LSST in the IR bands. We will present the design and the progress of its current pathfinder which is about to be completed.
Wednesday Nov 22, 10:30
Lusia Buzzo ()
Student Review: MCR review for Luisa Buzzo
MCR review
Tuesday Nov 21, 10:30
Jim Freeburn (Swinburne)
Student Review: Jim Freeburn MCR - Accessing the Dynamic Universe on Fast Timescales
Thursday Nov 16, 10:30
Roland Bacon (Lyon)
Colloquium: WST - The Wide Field Spectroscopic Telescope
The WST project aim to study and built an innovative 10-m class wide-field spectroscopic survey telescope (WST) in the southern hemisphere with simultaneous operation of a large field-of-view (5 sq. degree) and high multiplex (20,000) multi-object spectrograph facility with both medium and high resolution modes (MOS), and a giant panoramic integral field spectrograph (IFS). The ambitious WST top-level requirements place it far ahead of existing and planned facilities. In just its first 5 years of operation, the MOS will target 250 million galaxies and 25 million stars at medium resolution + 2 million stars at high resolution, and 4 billion spectra with the IFS. WST will achieve transformative results in most areas of astrophysics. The combination of MOS and IFS spectroscopic surveys is one of the key aspects of the project. It is very attractive because of the high complementarity between the two approaches. I will detail this innovative point using the example of the MOS and MUSE surveys performed in the CDFS region. The project aims to be the next major post-ELT project. It is supported by a large consortium of very experienced institutes plus ESO, representing 9 European countries and Australia.
Tuesday Nov 14, 10:30
Magdalena Hamel Bravo ()
Student Review: Metal Content of Outflows
Thursday Nov 9, 10:30
Chiara Buttitta (INAF)
Colloquium: The LEWIS Project: stellar kinematics of LSBs and UDGs in Hydra I
Ultra-diffuse galaxies (UDGs) are extremely faint (mu_0, g>=24 mag/arcsec^2) and diffuse (Re > 1.5 kpc) systems whose nature is unknown. To date, only about 20 UDGs were studied in detail and few of them have been spectroscopically analysed too. The LEWIS project is a large program, approved in the ESO period 108, to obtain the first homogeneous integral-field spectroscopic survey of UDGs in the Hydra I cluster of galaxies with MUSE@ESO-VLT. For all UDGs in Hydra I, the MUSE data will confirm the cluster membership, measure their stellar kinematics and stellar populations. In this talk, I would like to show results of the stellar kinematics for LSBs and UDGs in the Hydra I cluster. Stellar kinematics will permit us to investigate the mechanism that dynamically supports UDGs, recover the dynamical mass, and constrain the dark matter content.
Thursday Nov 2, 10:30
Kirsty Butler (IRAM)
Colloquium: Neutral Outflows in High-Redshift Dusty Galaxies
Outflows are crucially important for the gas budget and evolution of luminous star-forming galaxies and AGNs, with observed mass outflow rates of the same order as the star formation rate. Greater star formation and black hole growth leads to more intense feedback and outflows, resulting in self-regulated galaxy growth. Multi-phase observations show that the cool molecular and atomic gas dominate the mass and momentum budget of massive galaxy outflows which additionally remove the direct fuel for star formation. We target the molecular and atomic outflows at both cosmic noon and dawn where the most extreme star formation and black hole activity is found but where current observations are severely lacking. Techniques commonly used to detect outflows in the nearby universe with emission lines, are, however, challenging or impossible with current technology at high-redshift. Molecular absorption lines provide a powerful and reliable alternative which I will demonstrate with the OH+ and OH molecules in this seminar. With observations from the Atacama Large Millimeter/submillimeter Array (ALMA), we have demonstrated the power of molecular absorption lines in massive galaxy outflow studies at high-redshift, allowing for future more complex studies.
Thursday Oct 26, 10:30
Daniel Harsono (Institute of Astronomy, National TsingHua University)
Colloquium: Composition of planet-forming disks from ALMA and JWST
Planets are formed in accretion disks around young stars. Recent results suggest that the planet formation process begins in the earliest stages of star formation. ALMA has unveiled a diversity in the characteristics of planet-forming disks around young stars. Meanwhile, JWST is starting to provide us with the ingredients of these planets by studying the composition of icy dust grains and the hot inner disk. I will present recent results with ALMA and JWST that investigate the physical and chemical structure of young planet-forming disks relevant to the Solar System's history and the origin of water.
Thursday Oct 12, 10:30
Kirsten Banks (UNSW)
Colloquium: Investigating the spectro-seismic connection of red giant stars
Data-driven analysis methods can be used to infer the physical properties of red giant stars from spectroscopy when “gold-standard” asteroseismic data are unavailable. Through data-driven analysis of the optical and infrared spectra of red giant stars, we can derive the key asteroseismic quantities which are clear indicators of a star’s evolutionary phase. This makes it possible to efficiently differentiate core-helium-burning red clump stars, which are standard candles, from first-ascent red giant branch stars, which are not standard candles. This allows for future and existing large spectroscopic surveys, such as GALAH and APOGEE, to identify red clump stars with little red giant branch contamination. A large and reliable set of red clump stars would be extremely beneficial to Galactic archaeology studies that probe large volumes of the Galaxy, for example mapping the chemodynamical structure of the Milky Way to investigate its star formation history and evolution over time.

In this presentation, I will provide a comprehensive background on red giant evolution and the characteristics that distinguish red clump stars from red giant branch stars. I will also dive into the data-driven analysis I have performed to investigate the spectro-seismic connection of red giant stars and the future work that is in progress, including the information we expect preliminary abundance analysis to provide in the context of this investigation.
Thursday Oct 5, 10:30
Ben Farr (University of Oregon)
Colloquium: Hearing the forest for the trees: understanding LIGO/Virgo's plurality of singularities
Before the start of their current and fourth observing run (O4), the LIGO and Virgo detectors had already collected an impressive census of compact binary mergers in the local universe. By the end of O2 in August 2017 the LIGO Scientific Collaboration and Virgo Collaboration claimed a total of 10 binary black hole mergers and one binary neutron star merger. O3 spanned April 2019 through March 2020, included many significant discoveries (e.g., neutron star-black hole binaries, surprisingly massive black holes), and culminated in the third catalog of compact binary mergers, GWTC-3, raising the total catalog of confidently detected binary mergers to 90. I will present some of what ground-based gravitational wave astronomy has taught us about compact binaries over the last eight years, and what may lie ahead.
Thursday Sep 28, 10:30
Iris de Ruiter (Amsterdam)
Colloquium: Radio Sky Revelations: Navigating the Universe's Transient Mysteries with LOFAR
In this colloquium we will explore the dynamic radio sky with LOFAR, the Low Frequency Array. The first half of this talk will revolve around untargeted transient searches, which piggyback on the LOFAR surveys. We have developed an efficient pipeline that looks for transient in the image domain on timescales of seconds to hours. The use of fast imaging approaches and efficient filtering techniques has pushed us towards the ambitious goal of processing all LOFAR survey data. In this talk, I will detail some of these techniques and show some exciting preliminary results.

In the second half I will introduce targeted transient searches. Specifically, I will focus on the follow-up of short gamma-ray bursts, searching for coherent radio emission. This type of research focuses on the potential connection between fast radio burst and binary neutron star mergers. I will discuss some of the open questions in this area and potential avenues to tackle these questions.
Tuesday Sep 19, 10:30
Pratyasha Gitika ()
Student Review: Pratyasha Gitika-MCR
Student review
Thursday Sep 14, 10:30
Cathryn Trott (Curtin)
Colloquium: Exploring the ionization of the Universe with the SKA Observatory
The SKA will be the world's largest radio telescope when its construction is completed late this decade. One of the primary science goals of the SKA Observatory is the exploration of the early Universe, when the first stars, galaxies and quasars formed and reionized the primordial hydrogen and helium gas created in the Big Bang. I will introduce the SKA Observatory and its science program, and provide an update on construction progress. I will then describe the key early Universe experiments that will provide details about the Universe's evolution through hyperfine transitions in the radio part of the electromagnetic spectrum, and connect them to other molecular and atomic tracers from distant galaxies.
Thursday Sep 7, 10:30
Anna Ferre-Mateu (Instituto de Astrofisica de Canarias)
Colloquium: Hunting for ghostly ultra diffuse galaxies
Ultradiffuse galaxies (UDGs) have caught the attention of the extragalactic community since their re-discovery back in 2015. With effective radii as large as our Milky Way, but only 1% of its luminosity, these ghostly objects show a variety of bizarre properties: from high dark matter content to a lack of it, or unusually high GC counts but stellar populations more similar to classical dwarfs. From observations to simulations, several mechanisms have been proposed to form them, ranging from internal feedback to external processes, but none is able to explain the entire population as a whole.
Obtaining spectra with enough quality to perform a detailed stellar population analysis to solve the above problems is not trivial and requires a large sum of 10m telescope's time. In this talk, I will present our efforts to hunt some of these ghostly galaxies, while characterizing their kinematics, dynamical content, and stellar populations in order to shed light on their true nature.
Thursday Aug 31, 10:30
Zhuyun Zhuang (Caltech Astronomy)
Colloquium: Untangling the Chemical Evolution of Galaxies with Integrated-Light Spectroscopy
The relation between the metals in stars and gas, as well as how the abundances evolve in galaxies of different masses, can serve as a probe of galaxy assembly history. In this talk, I will discuss my recent progress on leveraging the IFU data from the Palomar and Keck telescopes to constrain the elemental abundances of nearby galaxies between 1e8-1e10Msun via integrated-light spectroscopy. I found that the low-redshift stellar mass-stellar metallicity relation has a discontinuity and change in slope around 1e9Msun. This dataset also enables us to make the first-ever apples-to-apples comparison of alpha-elements in the stars and ISM for star-forming galaxies beyond the Local Group. In addition, I will also discuss our results on the stellar abundances of two gravitationally lensed, quiescent galaxies discovered by the ASTRO 3D Galaxy Evolution with Lenses (AGEL) survey using Keck deep spectroscopy, and the implications on galaxy quenching at z>1.
Monday Aug 28, 16:00
Student Review: Aaron DTR
Tuesday Aug 15, 10:30
Wesley van Kempen ()
Student Review: Wesley van Kempen CoC
Thursday Aug 10, 10:30
Amelia Fraser-McKelvie (UWA/ICRAR)
Colloquium: The VERY complicated lives of disc galaxies
Back in 2019 I gave a colloquium at Swinburne with the title "the complicated lives of disc galaxies". I regret to inform you that disc galaxies have become no less complicated in the intervening time, and in fact I probably understand even less about what is going on. In this colloquium, I will update you on some recent results of low-redshift integral field spectroscopic surveys. Firstly: how many galaxies in the low-redshift Universe are actually discs? Then, the link between star formation quenching and an increase in stellar dispersion support: are all star-forming galaxies discs and all passive galaxies spheroids? Can we then say anything about the quenching mechanisms in passive galaxies – are bulges killing their host galaxy? Finally, I will speak about the dark art of comparing gas and stellar metallicity measures: should they be used as a proxy for one another, and if not, can the differences between the two tell us anything about the enrichment history of a galaxy?
Thursday Jul 27, 10:30
Keerthi Vasan G. C. (University California Davis)
Colloquium: Resolved studies of stellar Feedback at Cosmic Noon
Galaxy formation is regulated by the ejection of large-scale “outflows” of gas from their interstellar medium (ISM),
driven by energy released from Feedback processes such as star formation and/or accretion onto supermassive
black holes. These outflows can be studied at high redshifts via absorption line kinematics, but obtaining
good velocity resolution at these epochs is challenging.

In this talk, I will discuss results from our kinematic study of outflowing gas viewed “down the barrel” in 20 gravitationally lensed galaxies during Cosmic Noon (z=1.5−3.5) observed with Keck/ESI and Magellan/MagE, where lensing magnification enables good signal-to-noise and spectral resolution. This work represents the largest available sample of well-resolved outflow velocity structure at z > 2, and highlights the need for good spectral resolution to recover accurate properties essential for studies of Feedback. I will also discuss our ongoing efforts as part of the ASTRO 3D Galaxy Evolution with Lenses (AGEL) survey to discover and spectroscopically followup new gravitationally lensed systems from ground based surveys. Finally, I will briefly discuss our preliminary outflow kinematic results obtained from Keck/KCWI of a lensed, young, star-forming galaxy at z~2(CSWA13) where the spatial information enables us to connect the outflow velocities with local galaxy properties.
Thursday Jul 13, 10:30
Anna McLeod (Centre for Extragalactic Astronomy, Durham University)
Colloquium: Resolving feedback from massive stars in nearby galaxies
Feedback from massive stars plays a central role in shaping the evolution of galaxies. Conversely, different galactic environments play a central role in regulating the impact of massive stars. Yet, despite a solid qualitative understanding of feedback, our quantitative knowledge remains poor. Until recently, only a small number of star-forming regions had adequate observational information on both gas and stars needed for detailed stellar feedback studies.

Over the past decade, integral field units (IFUs) have revolutionized our approach to resolved stellar feedback studies in nearby galaxies. In this talk I will present recent results of large IFU nearby galaxy surveys, showcasing how these can be used to simultaneously characterize the feedback-driven interstellar medium and individual feedback-driving stars up to Mpc distances, and I will discuss how this enables the first empirical quantification of the interdependence between stellar feedback and the environments massive stars form in. Lastly, I will also be talking about how IFU data can lead to truly serendipitous discoveries.
Thursday Jun 15, 10:30
Mark Suhr (Swinburne)
Student Review: CoC review: High Redshift Supernovae as Tools to Understand the Early Universe
Thursday Jun 8, 10:30
Guifre Molera Calves (University of Tasmania)
Colloquium: The ESA JUpiter ICy moons Explorer mission
The largest European space mission ever, the Jupiter Icy Moons Explorer (JUICE) was launched in April 2023 after a decade of preparations. JUICE’s 8-year journey to reach the Jupiter system has now begun. The mission will make detailed observations of the giant gas planet and its three large ocean-bearing moons – Ganymede, Callisto and Europa – with a suite of remote sensing, geophysical and in situ instruments. The mission will characterise these moons as both planetary objects and possible habitats, explore Jupiter’s complex environment in depth, and study the wider Jupiter system as an archetype for gas giants across the Universe.

To achieve the goals the mission is equipped with 10 different instruments on-board of the craft, and one here on the Earth. The Planetary Radio Interferometry and Doppler Experiment (PRIDE) of the JUICE mission conducts observations of the spacecraft with large parabolic radio telescopes from the ground. PRIDE and the five radio telescopes from the University of Tasmania are conducting observations of the craft since day one, what is known as the New Earth Commissioning Phase (NECP). In this talk, I will cover the goals of the mission, the opportunities during the cruise-phase, the role that PRIDE team plays in the upcoming years, and the first scientific results achieved by the group.
Thursday May 25, 10:30
Alfred Castro Ginard (Leiden Observatory, Leiden University)
Colloquium: Mapping the Milky Way with the stars (un)seen by Gaia
In this talk, I will present current efforts in mapping our own Milky Way. I will focus on how the wealth of data from the Gaia mission has redefined our understanding of the open cluster population, which is an excellent tracer of different Galactic structures. Particularly, I will review how machine learning methods have improved the detection of open clusters and the characterization of their properties. I will also go through how we use the newly defined open cluster census in a broader Galactic context, by using them as tracers of the Milky Way spiral arms. Finally, I will discuss how we can estimate the Gaia Survey Selection Function, and how completeness studies can be incorporated to have a better insight into our Milky Way.
Thursday May 18, 10:30
Jayden Newstead (University of Melbourne--Centre for Dark Matter Particle Physics)
Colloquium: Oh the places you'll go (with dark matter)
Dark matter, an enigmatic and elusive phenomena, continues to perplex and challenge the scientific community. In this talk we will tour through the realms of particle, nuclear, atomic, and astro-physics, surveying the rich interdisciplinary research that propels our search for dark matter. The efforts of astrophysics and cosmology provide us with the necessary cosmic context, while the fields of nuclear and atomic physics ground us, informing and guiding the search for dark matter in the laboratory. We will explore the compelling evidence for the existence of dark matter and how we can best determine its true nature.
Thursday May 11, 10:30
Emille E. O. Ishida ()
Colloquium: Big data and small humans: enabling scientific discovery in the era of big data
The significant increase in volume and complexity of data resulting from technological development is a common challenge faced by modern astronomy. More sensitive detectors and large scale experiments are currently overwhelming researchers who are obliged to turn to automatic machine learning algorithms in order to filter, order or pre-select potentially interesting subsets of the original data for further scrutiny. In this scenario, algorithms need to be carefully designed to be flexible, selecting scientifically interesting/useful examples in accordance with the expert's needs, thus optimizing the distribution of human efforts in scanning a large data set. In this talk I will show a few examples of adaptive learning environments, where expert feedback is incorporated into the learning algorithm. In the context of the Fink broker and the upcoming Vera Rubin Observatory Large Survey of Space and Time (LSST), I will describe the challenges of transitioning from toy data to real scientific data sets, and discuss how we can optimize scientific results with minimum labelling efforts.
Thursday May 4, 10:30
Emily Wisnioski (Australian National University)
Colloquium: Connecting Epochs: how the chemo-dynamical evolution of disks over cosmic time is imprinted on local galaxies
Galaxy evolution is an inherently messy processes to disentangle. To achieve a holistic understanding we need to combine our observations and models to ask: how does the Milky Way's evolutional path fit within modern observations of the high-z universe? Kinematics and structural studies have revealed that the majority of 'normal' star-forming galaxies at cosmic noon host thick disk-like structure and a turbulent gas-rich interstellar medium while new CII observations reveal possibly cold disks at cosmic dawn. Chemical studies reveal that the resolved abundance patterns of disks are also evolving with radial gradients being subdominant at early times. How does this relate to the state-of-the art models of the MW's past? I will present results that show how combining new analytic models (e.g. Sharda et al. 2021 and Leaman et al. 2022) with high redshift surveys of molecular and ionised gas and local galactic/extragalactic archeology studies can provide insight to the evolutionary history of local galaxies including the Milky Way. I will discuss observational results within the framework of theoretical models for the formation of the local stellar age-velocity dispersion relation, the size-scale height relation, and history of metallicity gradients in local group galaxies.
Thursday Apr 20, 10:30
Aditi Vijayan (Australian National University)
Colloquium: A Simulator's Guide to Multiphase Outflows in the Galaxy
Outflows, generated either due to supernova (SN) activity in the disc of a star-forming disc or through the SMBH activity in a larger galaxy, are critical in understanding galaxy evolution. Such outflows are a complex phenomenon which can be studied using HD simulations. In this talk, I will discuss 3-D HD simulations that I ran to study the properties of outflows in a Milky Way-type star-forming galaxy. I will discuss how feedback creates multiphase outflows and how they appear in X-rays. I will share what I found about diffuse X-ray emission from the CGM and its relationship with the underlying gas properties.
Friday Apr 14, 10:30
Jacob Askew ()
Student Review: Jacob Askew MCR
Thursday Apr 13, 10:30
Chris Lidman (ANU)
Colloquium: Supernova Cosmology
It has been a quarter of a century since type Ia supernovae were first used to show that the university is accelerating. Over that 25 years, the number of supernovae used to probe the acceleration has increased in number by two orders of magnitude. Yet we still do not understand what drives the acceleration. Dark energy is one of several possibilities. The Legacy Survey of Space and Time will detect at least an order of magnitude more supernovae. Spectroscopically classifying every single event will be impossible. Instead, classification will have to be done using supernova light curves and host galaxy redshifts. In this talk, I will use data from the Dark Energy Survey to show that this approach provides competitive and unbiased constraints on dark energy.
Thursday Apr 6, 15:00
Carlos Coello Coello (Instituto Politécnico Nacional)
Colloquium: Where is the Research on Evolutionary Multi-Objective Optimization Heading to?
The first multi-objective evolutionary algorithm was published in 1985. However, it was not until the late 1990s that the so-called evolutionary multi-objective optimization began to gain popularity as a research area. Throughout these 38 years, there have been several important advances in the area, including the development of different families of algorithms, test problems, performance indicators, hybrid methods and real-world applications, among many others. In the first part of this talk we will take a quick look at some of these developments, focusing mainly on some of the most important recent achievements. In the second part of the talk, a critical analysis will be made of the by analogy research that has proliferated in recent years in specialized journals and conferences (perhaps as a side effect of the abundance of publications in this area). Much of this research has a very low level of innovation and almost no scientific input but is backed by a large number of statistical tables and analyses. In the third and final part of the talk, some of the future research challenges for this area, which, after 38 years of existence, is just beginning to mature, will be briefly mentioned.
Thursday Apr 6, 10:30
Toby Brown ()
Colloquium: VERTICO: The influence of environment on the gas-star formation cycle of galaxies
The Virgo Environment Traced in CO Survey (VERTICO) is an Atacama Large Millimeter/submillimeter Array Large Program that has observed the influence of environment on molecular gas by mapping its distribution and kinematics across 51 Virgo Cluster galaxies on sub-kpc scales. In this talk, I will showcase results from first round of VERTICO papers that reveal how environmental mechanisms perturb the distribution, amount, and composition of the interstellar medium in cluster galaxies. I will also show that mechanisms such as ram pressure stripping and starvation actively reduce the molecular gas density and star formation efficiency (SFE) of the ISM, resulting in lower star formation activity.
Thursday Mar 30, 10:30
Laura Keating (CAS visiting fellow)
Colloquium: Timing Reionization with Quasar Absorption Lines
The epoch of reionization marks the last major phase transition of the Universe, when photons emitted by the first structures ionized and heated the surrounding gas. A complete understanding of reionization would reveal the properties of the first stars and galaxies, as well as increasing the precision to which the intergalactic medium can be used for cosmology. It has been a long standing problem to understand why large spatial fluctuations in the ionization state of the intergalactic medium are observed above redshift 5, when reionization was assumed to already be completed by redshift 6. Different scenarios were proposed to explain this, such as fluctuations in the UV background or gas temperature. However, neither of these scenarios are completely satisfactory, with both requiring strong assumptions to be made. My research has shown that a more natural explanation for these large scale fluctuations is a later end to reionization (Kulkarni, Keating et al. 2019, Keating et al. 2020a). In this colloquium I will present results from my radiative transfer simulations of cosmic reionization and compare them with observations of the Lyman-⍺ forest, absorption lines observed in quasar spectra probing intergalactic gas. I will show that matching the observed statistics of the Lyman-⍺ forest and its connection to surrounding galaxies requires reionization to have ended later than previously thought, with islands of neutral hydrogen still found at redshift 5.3. My theory has now been independently verified by multiple groups, and is widely accepted as the leading explanation for the statistics of the intergalactic medium above redshift 5.
Monday Mar 27, 13:30
Ben Scott (Swinburne)
Student Review: Ben Scott's Confirmation of Candidature review
Thursday Mar 23, 10:30
Douglas Scott (University of British Columbia)
Colloquium: ON DIPOLES
The sky can be decomposed into low-order modes, specifically using spherical harmonics. The monpole is the "DC" component, while the dipole is the variation that makes one side of the sky different than the other. Both of these are coordinate dependent, in other words they can vary for different observers. In particular, a moving astronomer will see a dipole in the energy of photons, as well as in the aberration of those photons, in the number density of distant sources and in other observables. So is the observed dipole just due to our own motion, or could some of it be "intrinsic"? What would that even mean?
Thursday Mar 23, 14:30
Renee Key (CAS)
Student Review: MCR: Renee Key
Wednesday Mar 22, 11:00
Natasha Van Bemmel (Swinburne)
Student Review: Natasha Van Bemmel CoC
Exploring the Optical and Infrared Fast Transient Universe
Tuesday Mar 21, 10:30
Hugo Walsh ()
Student Review: Hugo Walsh's Confirmation of Candidature
Cyber-Human Discovery Systems: Enhancing Human Performance at Visual Discovery for Next-Generation Space Data
Thursday Mar 16, 10:30
Karelle Siellez ()
Colloquium: Chasing the transients in the Southern Sky : a quest for gravitational waves counterparts!
In 2017, we have entered the multimessenger era! With the discovery of the compact binary neutron stars merging, we have obtained, for the first time in human history, a gravitational wave detection, coincident with a gamma ray burst emission: a beamed jet of high energy gamma particles accelerated at the speed of light producing an afterglow in all wavelengths, and a kilonova observed with optical telescopes. Since that event occurred on the 17th of August 2017, breakthroughs have been made allowing us to better understand the equation of state of neutrons stars, the physics of the jet and the cosmology implications that could end the Hubble tensions.

But since then, we haven't been able to reproduce such a multi messenger observation despite years of data acquired. After reviewing the odds of such an event occurring, I will explore different new technic that I am part of developing and will demonstrate how the Southern Sky could be the host of the next multimessenger event in 2024!
Tuesday Mar 14, 13:00
Kate Wilson (UNSW)
Colloquium: Teaching and Assessing for Gender Equity (ASTRO 3D special colloquium)
If you’re a woman in STEM, especially in the physical sciences, then often in classrooms and in meetings, you’re very much in the minority – in fact sometimes you’re the only woman in the room.

There is a general recognition (although not universal agreement) that the lack of women in STEM is not a good thing. It’s not a good thing for women because they’re being excluded from an important field of human endeavour. It’s not a good thing for STEM because potentially valuable contributions are being lost, and diversity dividends being thrown away. So, what is keeping women out of STEM?

Unfortunately, there are many reasons, and few of them are easy to address as individual educators.

But as educators, we can change the way we teach and the way we assess our students. And this doesn’t have to mean compromising on what we teach, or disadvantaging the boys/men in our classes, or dumbing down our assessments. It means teaching in ways that support all learners and examining our existing tasks for bias, and then adjusting them appropriately to remove that bias.
Thursday Mar 9, 10:30
Oliver Anagnostou (University of Melbourne)
Colloquium: Collisional N-body simulations: black hole binary mergers and my love/hate relationship with FORTRAN
Dense star clusters have long been proposed as ideal factories for compact binary mergers, which we now know are relatively common thanks to gravitational wave detections. N-body simulations can be used to model these star clusters, the compact binary mergers they host, and the gravitational waves they produce. In this talk, I will discuss some details of NBODY6, a state-of-the-art N-body code used for simulating star clusters, including its inner workings and how it is being used by both me and the population synthesis community as a whole. I will also describe my extensive upgrades to the code, focusing on supernovae physics and post-merger remnant properties for second-generation black holes. I will highlight how my new version of NBODY6 will hopefully enable researchers to learn more about the emerging population of black hole binary mergers.
Tuesday Mar 7, 10:30
Nimas (Swinburne)
Student Review: Nimas CoC
Friday Mar 3, 10:30
Matt Miles ()
Student Review: The MeerKAT Pulsar Timing Array
Tuesday Feb 28, 14:00
Tyler Hughes (Swinburne)
Student Review: Application of Machine Learning for Dark Matter Substructure Detection in Strong Lenses
Tyler's MCR Review.
Tuesday Feb 21, 13:00
Atharva Kulkarni ()
Student Review: The chromaticity of pulsar timing: an application to PSR J0437-4715
Atharva Kulkarni's CoC
Tuesday Feb 21, 10:30
Student Review: Adam Ussing MCR
Password: 059918
Thursday Feb 16, 10:30
Jonah Gannon (Swinburne)
Colloquium: Ultra-Diffuse Galaxies (UDGs) and the Stellar Mass-Halo Mass Relationship
The stellar mass-halo mass relationship is a fundamental scaling relationship connecting galaxies from dwarfs to giants to their dark matter halos. This relationship is currently key to our understanding of the complex interplay between the many modes of feedback (e.g., stellar winds, supernovae, AGN) and star formation in galaxies. However, recently a population of large, low surface brightness ultra-diffuse galaxies (UDGs) have questioned our understanding of galaxy formation in the dwarf galaxy regime. UDGs have been found to reside in dark matter halos of widely varying mass. While many likely reside in normal dark matter halos for their stellar mass, some exhibit an extreme lack of dark matter while yet others are extremely dark matter rich. In this talk, I give an overview of the current observational evidence for UDGs residing in massive dark matter halos. I place particular emphasis on my own Keck observations which have provided support for UDGs unexpected stellar mass-halo mass positioning and that have revealed the internal structure of their halo (i.e., core vs cusp nature). I discuss how these observations currently inform the various proposed formation scenarios of UDGs and show the outstanding problem UDGs pose leading simulations of galaxy formation. I conclude with a brief discussion of the important future goals of the field.
Tuesday Feb 14, 10:30
Stuart Lyall (Swinburne)
Student Review: Stuart Lyall DTR
Wednesday Feb 8, 10:30
Connor Bottrell (University of Tokyo)
Colloquium: Connecting the observable to the non-observable at a crossroads of observational and computational galaxy astronomy
The growth of structure in the Universe is predicated upon the assembly of large structures from smaller structures. Gravitational interactions, collisions, and subsequent mergers between galaxies are therefore an underpinning ingredient of galaxy evolution. Meanwhile, the strong gravitational and tidal forces involved in close galaxy encounters can be drivers of morphological and kinematic transformation, but also the acceleration of physical processes such as star-formation, black hole accretion, and chemical redistribution. So, how are current galaxy properties connected to the details of their recent and early assembly histories? What role does assembly have in driving the diversification of galaxies and their physical properties from the primordial porridge of the early Universe to today? The challenge is that the true collision record of a galaxy is not accessible observationally — thereby hindering such connections. In an effort to tackle this challenge, I will show how realistic synthetic observations of galaxies from hydrodynamical simulations, statistics, and machine learning can be used to unravel connections between the observable and the intrinsically unobservable.
Tuesday Feb 7, 10:30
Antonia Fernandez Figueroa (Swinburne)
Student Review: CoC
Thursday Feb 2, 10:30
Michael Murphy (Swinburne)
Colloquium: Fundamental physics with solar twins
The Standard Model of nature's laws provides no explanation for the fundamental constants, like electromagnetism's strength, alpha. It is therefore up to experiments to test whether fundamental constants are, indeed, constant and universal, or instead vary and depend on other physical parameters. I will describe a new probe of alpha's constancy within our Galaxy, solar twin stars, and show our first results which have an ensemble precision of 12 parts-per-billion. This is already the best astronomical measurement of any fundamental constant so far. The results derive from archival high-resolution optical spectra (HARPS) from the ESO 3.6-m telescope, so there is considerable scope for extending them using larger facilities. Our goal is to map alpha across the Milky Way and, importantly, its widely-varying dark matter density field. This will be a completely new, direct test of physics beyond the Standard Model. I will report our discovery of the most distant solar twins and analogues, up to 4kpc closer to the Galactic Centre, as the first step towards that goal, and outline current and future work.
Tuesday Jan 31, 10:30
Student Review: Daniel McPherson DTR