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News Annual Scientific Meeting News Participants Program Posters Events Opening Reception ESO Agreement Signing Harley Wood Public Lecture ASA Conference Dinner Introduction To Machine Learning Prizes Bok Prize Charlene Heisler Prize Ellery Lectureship Harley Wood Lecture Louise Webster Prize Policies Sponsors Harley Wood Winter School

Astronomical Society of Australia's Annual Scientific Meeting – Posters

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P1: Machine learning methods for radio host cross-identification with crowdsourced labels
Matthew ALGER, The Australian National University

We propose a machine learning approach for radio host cross-identification, the task of finding the infrared host galaxy corresponding to radio emissions. Traditional machine learning requires a large amount of labelled training data, which can be difficult or expensive to acquire. Radio Galaxy Zoo is a citizen science project that provides a large number of radio host cross-identifications, which may be used as training labels for machine learning algorithms. However, these cross-identifications may be incorrect, as they are assigned by non-experts. We investigate the use of crowdsourced training data from the Radio Galaxy Zoo to train machine learning methods for radio host cross-identification in the CDFS field. We find that despite the inaccuracies in the cross-identifications provided by the crowd, Radio Galaxy Zoo labels are still useful for training. We show that methods trained on Radio Galaxy Zoo cross-identifications achieve accuracies comparable to those trained with expert cross-identifications.

P2: Investigating black hole formation with VLBI astrometry
Pikky ATRI, International Centre for Radio Astronomy Research, Curtin University

Even though the first black hole (BH) detection was made decades ago, we still lack observational constraints on their formation mechanisms. It is known that black holes form either via direct collapse of a sufficiently massive star or a supernova explosion. Black holes formed by direct collapse have low natal kick velocities as compared to those formed by supernova explosion which suffer a recoil kick at the time of their formation. Thus, measuring the natal kick distribution of black hole X-ray binaries (BHXRBs) will help in determining what fraction of them receive natal kicks, how strong those kicks are, get a mass constraint which differentiates the two pathways and thereby get observational constraints on supernova mechanisms. The natal kick distribution is a poorly-constrained input parameter in N-body simulations of globular clusters that seek to predict black hole merger rates. Black hole natal kicks can be inferred by measuring their full three-dimensional space velocities, via the Very Long Baseline Interferometry technique combined with radial velocity information from optical or infrared bands, inferring Galactocentric orbits, and determining where and how the BHXRB was born. Currently, we have a small sample set of 7 BHXRB systems with measured proper motions which is insufficient to constrain BH formation mechanisms and so a larger sample of systems is needed. In this poster we will present preliminary results for one such low mass BHXRB source, GX 339-4.

P3: Keck spectroscopy of z ~ 7 galaxies: probing the physics of reionisation
Stephanie BERNARD, University of Melbourne

When and how did reionisation occur in the first billion years? What are the properties of the sources that contributed to the process? Spectroscopy of sources during reionisation can provide insights into this period, by setting constraints on the evolution of the neutral gas fraction with redshift, and on the topology of hydrogen reionisation. As they are extremely faint and their spectra are highly redshifted to near-infrared wavelengths, observing galaxies during reionisation is challenging; nevertheless, the Keck MOSFIRE instrument has been used to detect Lyman-alpha emission from a handful of intrinsically bright galaxies all the way to z = 8.7. These bright sources, however, are not expected to be representative of the galaxy population that existed at the time. I will present our program to use MOSFIRE to observe intrinsically faint, gravitationally-lensed galaxies during reionisation, identified in the large Grism Lens-Amplified Survey from Space (GLASS) program conducted using the Hubble Space Telescope. I will also present spectroscopic confirmation of the faintest galaxy yet discovered during the reionisation epoch.

P4: The USQ Astrophysics Group and Mt Kent Observatory
Bradley CARTER, University of Southern Queensland

The USQ Astrophysics Group is currently involved in an upgrade of Mt Kent Observatory to enhance its role in Australian stellar astronomy and planetary systems research. An overview of developments and plans are presented.

P5: The true nature of newly discovered ultra-faint Milky Way satellites
Blair CONN, Research School of Astronomy and Astrophysics

The ultra-faint dwarf galaxy candidates being uncovered in the Southern skies represent a wide variety of stellar systems and raise fundamental questions regarding their origin and nature. An increasing number of these systems are found within relative proximity to the Magellanic Clouds suggesting they might be part of an in-falling group. The relatively shallow nature of the discovery observations leaves crucial questions unanswered and so the Stromlo Milky Way Satellite Survey team has embarked on an ambitious project to physically and chemically characterize these stellar systems. I will demonstrate how DECam, Magellan and Gemini all play an important role in the discovery and characterization of these new objects. Our deep data from Gemini are now revealing how unique each of these systems are, and in particular, I will show some preliminary results from our analysis.

P6: Mini-HIPPI: A high precision polarimeter for small telescopes
Daniel Vincent COTTON, University of New South Wales

We showcase Mini-HIPPI (Miniature HIgh Precision Polarimetric Instrument), a stellar polarimeter weighing just 650 grams but capable of measuring linear polarisation to approximately 10-20 parts-per-million. Mini-HIPPI is largely 3D-printed and quite inexpensive; its operation is based on the use of a Ferroelectric Liquid Crystal (FLC) modulator. It can easily be mounted on a small telescope and allows study of the polarisation of bright stars at levels of precision which are hitherto largely unexplored. We present some results obtained with Mini-HIPPI on a 35 cm telescope. These include measurements of polarised standard stars showing good agreement with predicted values, and measurements of a number of bright stars that agree well with those from other high-sensitivity polarimeters. We also present time-series data of some bright stars, including the binary system Spica, which shows polarisation variability around the orbital cycle.

P7: The Next Step in TeV Gamma-Ray Astronomy - Status of the CTA (Cherenkov Telescope Array)
Roland CROCKER, ANU

The CTA will comprise about 130 Cherenkov imaging telescopes spread over two sites (northern and southern hemispheres). It will provide a transformational advance in our understanding of the high energy sky by probing the particle acceleration and interaction taking place in nature's extreme objects. It will also provide a new view on the potential to understand the makeup of dark matter. This poster provides a snapshot of CTA's present status in terms of construction, science potential and linkages to other areas of Australian astronomy.

P8: Kinematic Traceback of Nearby Young Moving Groups: A Bayesian Approach
Timothy CRUNDALL, ANU

Understanding the processes surrounding both the formation of young stars and their planetary systems relies on having accurate ages. There is a reasonably reliable age scale for stars older than 20 Myr from measuring the Lithium Depletion Boundary (LDB), but there is as of yet no consistent means of age calibration below 20 Myr. One approach attempting to bridge this gap is based on the kinematics of stellar associations believed to have a common origin. Over the past decade astronomers have proposed various ages of known collections of co-moving stars by inspecting the volume of occupied space as these stars are projected backwards through time. These kinematic ages have been consistently inconsistent with individual star ages provided by other techniques such as isochrone fitting or lithium depletion boundary methods. Kinematic fi ts also hinge critically on which stars are predetermined to be members of the association. This thesis unveils a new approach to finding the most probable time corresponding to the smallest occupied volume of a collection of stars. Whereas classical approaches have failed due to large uncertainties in stellar astrometry, this Bayesian approach incorporates uncertainties by assigning each star a probability distribution function, and performing an analysis on these PDFs. This approach is demonstrated on a synthetic data set of stars with only 2 phase-space dimensions. This technique is applied to the TW Hydrae Association on both the whole set of candidate members as well as a core set. This yields approximate ages of 5 Myr and 8 Myr respectively. I also lay the groundwork for utilising machine learning to dynamically model moving groups with non-discrete stellar memberships. Incorporating continuous membership probabilities into the actual group ts will ultimately avoid the challenge of ascribing ts on groups with predetermined membership lists.

P9: Measuring and shifting attitudes in formal and informal astronomy education and public outreach
Michael Thomas FITZGERALD, Edith Cowan University

In this talk, I will present the results of a recent review of attempts to shift student ‘attitudes’ towards astronomy at the undergraduate level. Typically most of these attempts have been in the context of large enrolment first year courses in the United States. The vast majority of these attempts to shift ‘attitude’ have proven unsuccessful. This lack of success can be attributed to a number of major factors. Firstly, expecting substantial changes in attitude to occur on timescales as short as a semester is unrealistic. Secondly, most undergraduate courses don’t *explicitly* address improving student attitudes but rather expect it to change as a natural outcome of the course itself. Thirdly, most people who have self-selected to undertake astronomy courses are already “maxxed-out” such that ceiling effects come into play where improvement is not numerically possible. Finally, there hasn’t been a high quality validated instrument to measure attitudes towards astronomy…. until now. We present our work on designing a new survey instrument allowing measurement of eight attitude related factors: attitudes towards astronomy, attitudes towards science in general, practical work in science, instructor related attitudes, self-efficacy in science, beliefs about the benefits of science, their opinion of science outside of school and their perceived personal relevance of science. This instrument has been validated using formal high school students, but is also likely applicable to undergraduate students and informal groups with slight tweaking. Future work includes validating the instrument with many different groups.

P10: Our Solar Siblings: Status at the three year point.
Michael Thomas FITZGERALD, Edith Cowan University

Our Solar Siblings: Status at the three year point. Our Solar Siblings is a three year old high school level astronomy education project linking teachers with the Las Cumbres Observatory network of 2 metre, 1 metre and 0.4 metre telescopes distributed around the global. The project focusses on the Year 10 curriculum strand of “Whats out there in the universe” and “The Big Bang” while providing scientific mentor support for student research projects at any year level, but typically within Year 11 and 12. In the last year, the curriculum materials that teachers use have been majorly overhauled, a moodle space has been created and images from the project have been used for a major exhibition. Student research projects have included multiple investigations of RR Lyraes in globular clusters, variability surveys of open clusters, independently measuring the distance to M31 using Hubble’s first variable, using student-collected photometry and spectroscopy to measure H0, classifying a stellar association of unknown classification and identifying and setting likelihoods for binary open clusters amongst others. It is planned to undertake a major promotion and recruitment drive in 2017 & 2018.

P11: astroEDU: Peer Review for International Astronomy Education Activities
Michael Thomas FITZGERALD, Edith Cowan University

Developing and finding astronomy education resources with high-quality is a challenge to astronomy communicators and educators around the world. Even though hundred, thousands of resources exist, as well as many resource repositories to find them, the quality of resources is highly variable as they are not updated regularly or only have limited content review. astroEDU, since 2013 has been addressing these issues and more by following a peer-review process. Each activity submitted is reviewed by an educator and a professional astronomer, balancing both the scientific and educational value of the content. Following a peer-review process used in scholarly journals, each activity submitted is reviewed by an educator and a professional astronomer, balancing both the scientific and educational value of the content (Russo, Gomez, et al. 2014). This talk will discuss why quality matters, challenges in peer-review, how to create and adopt good resources, and more. astroEDU has largely, until this point, published articles largely in English with most activity authors based in the United States, United Kingdom and Continental Europe. This has been during the pilot stages of the project. We are now looking to spread the peer reviewed education model beyond the boundaries of the largely English speaking world and provide activities in other languages. This language integration will be facilitated by the on-going developments within the astroEDU team to upgrade and open up social interactivity throughout the platform as well as facilitating high quality peer review. The new developments within the astroEDU platform, the recent activity and submissions, our plans for involving multiple language groups and our future directions will all be outlined.

P12: Evolution of hydrogen-deficient donors in accretion-powered millisecond pulsars
Adelle GOODWIN, Monash University

Accretion powered millisecond pulsars (AMSPs) are neutron stars with weak ($\sim 10^8$ G) magnetic fields that are accreting matter from a low mass companion star. Typically transient X-ray sources, these systems are observed to exhibit coherent X-ray pulsations as well as type I thermonuclear bursts periodically. Observations of these sources have demonstrated that burst oscillations trace the neutron star spin and are also the “missing link” between rotation-powered radio pulsars and the “recycled” variety with millisecond spins. Numerical studies of these systems have been successful in modelling their population as a whole, but individual systems are often insufficiently constrained to reliably determine their prior evolutionary history.\\ We have obtained constraints on the neutron star mass, radius, accretion rate, fuel composition and distance to the source using a Markov Chain Monte Carlo method we have recently developed to match observations of AMSPs in outburst with a semi-analytic ignition model. We find a neutron star mass of $\approx$ 1.6 M$_{\odot}$ is required, which is higher than the traditionally adopted value of 1.4M$_{\odot}$ and a H fraction of $\approx$ 0.45 for the accreted fuel. This implies the neutron star has gained mass through accretion and that the companion star has undergone significant hydrogen-burning, placing a strong lower bound on its initial mass. We then use MESA stellar evolution models to run evolutionary tracks of individual accretion powered millisecond pulsars in low mass X-Ray binary systems (such as SAX J1808.4--3658, the most well studied of its type) to gain insight into the evolution of AMSPs and their progenitors.

P13: Future Plans for the Parkes Radio Telescope in the era of the SKA
Jimi GREEN, CSIRO Astronomy and Space Science

The Parkes radio telescope, known affectionately as ‘The Dish’, is located ~380 km west of Sydney, Australia, and has been in operation since 1961. It is a 64-metre parabolic antenna, with receiver systems capable of observing from 700-MHz to 26 GHz with bandwidths up to a GHz, and it is part of the CSIRO Australia Telescope National Facility (ATNF). The Dish has continued to be at the forefront of radio astronomy and technology research, having had many improvements, including a progressively upgraded dish surface to enable higher frequencies, a new focus cabin to extend the receiver capability, and a number of scientifically productive receivers. This receiver suite has included the 13-beam 20cm multibeam receiver which enabled unprecedented surveys of atomic hydrogen in the Southern sky, and helped discovered approximately half the known population of pulsars, as well as in more recent years discovering the first Fast Radio Burst. The Parkes Radio Telescope was recognised as a Square Kilometre Array (SKA) Pathfinder in 2016, on the basis of Phased Array and Wideband Feed technology development. I will present a summary of the current status of the capabilities of the Parkes Radio Telescope, recent activities including the commissioning of a Phased Array Feed built for the Max Planck Institute for Radio Astronomy, and outline the planned developments for the coming years. This includes exploring the technologies appropriate for the SKA: an Ultra-Wideband single pixel feed operating from 700 MHz to 4 GHz, and a cryogenically cooled Phased Array Feed operating in the region of 700 MHz to 2 GHz. I will also summarise the current backend (digitizing, sampling and processing) options, together with those planned for the coming years – including a graphical processing unit based single cluster system. I will also comment on Parkes based education and outreach programmes.

P14: Aegean 2.0
Paul HANCOCK, Curtin University

This poster describes many of the advances that have been made in the last few years in the area of radio source finding. In particular this work focuses on solving many of the problems presented by wide-field images from SKA precursor telescopes.

P15: The GALAH Survey: An Application of Machine Learning
Arvind HUGHES, Macquarie University

Astronomy has seen rapid developments in the quantity of data available. The resulting datasets are too large for an individual to analyse. However by applying sophisticated statistical methodologies it is possible to extract information efficiently. My thesis uses advanced statistical algorithms to identify solar twins, metal poor stars and unknown objects in the GALAH survey.

P16: The GAMA Legacy ATCA Southern Survey (GLASS)
Minh HUYNH, CSIRO / UWA

The GAMA Legacy ATCA Southern Survey (GLASS) is an ATCA Legacy survey which will cover the full GAMA G23 field with up to 3000 hours on ATCA over six semesters. The full 50 square degrees will be imaged at two 4cm bands, reaching ~30 and ~50 microJy rms sensitivity at 5.5 and 9.5 GHz, respectively. With this unique dataset we will: 1) study the properties and evolution of AGN, and 2) calibrate and investigate non-thermal and thermal radio star formation rate measures in normal galaxies. The G23 region is set to be one of the foremost legacy regions in the southern sky. Existing data include deep UV-FIR imaging, 60,000 optical spectra, and full value-added properties such as group catalogues, SFRs, stellar masses, dust masses, metallicities, photometric redshifts and full SED fits. The future Wide Area VISTA Extragalactic Survey (WAVES) will also target the GAMA G23 region, going to fainter magnitudes (r < 22) than GAMA. Existing radio data of G23 comes from relatively shallow large-area surveys: GLEAM/MWA (70-230 MHz), SUMSS (843 MHz) and NVSS (1.4 GHz). G23 will also be observed by ASKAP as part of the EMU and DINGO Survey Science Projects. G23 is a top priority field for EMU Early Science, which will use 3 x 300 MHz bands across 0.7 to 1.8 GHz to reach ~45 microJy/beam. GLASS is the only deep wide-area high-frequency survey with this scope of complementary data until SKA Phase 1, as such it will be a unique test-bed for SKA science. Here we present the preliminary results from the first semester of observing.

P17: Radio Galaxy Zoo: The Search for HyMoRS
Anna D KAPINSKA, International Centre for Radio Astronomy Research (ICRAR)

Hybrid morphology radio sources (HyMoRS) are a rare type of radio galaxy that display distinct Fanaroff-Riley classes on opposite sides of their nuclei. To increase number statistic in the analyses of hybrid morphology radio sources, we embarked on a large-scale search of these sources within the international citizen science project, the Radio Galaxy Zoo. Here, we present 25 new candidate hybrid morphology radio galaxies, at redshifts 0.07 < z < 1.0. For the first time, we investigate the hosts of HyMoRS: for a third of the candidates spectroscopic observations reveal a variety of hosts including quasars, green bean galaxies, and high- and low- excitation galaxies. Although the origin of the hybrid morphology radio galaxies is still unclear, this type of radio source starts depicting itself as a rather diverse class. We discuss hybrid radio morphology formation in terms of the radio source environment (nurture) and intrinsically occurring phenomena (nature; activity cessation and amplification), showing that these peculiar radio galaxies can be formed by both mechanisms. Furthermore, we demonstrate the efficacy and great value of the Radio Galaxy Zoo in studies such as this one. The publication of the Radio Galaxy Zoo Data Release 1 catalogue is planned for late 2017.

P18: News from Jupiter - Juno mission and supporting observations from ground telescopes
Lucyna KEDZIORA-CHUDCZER, UNSW

Juno spacecraft made already six flybys taking data of Jovian atmospheric composition, magnetic fields and gravity that will help to answer very fundamental questions about planetary formation, evolution and physics. I will discuss the most detailed maps of Jovian clouds and radiometric measurements that probe planetary weather systems to unprecedented depths. 

Auroras are formed in high-latitude atmospheric layers as a result of charged particles precipitating from planetary magnetospheres. I will show the latest observations of Jupiter aurora from Juno and ground telescopes. I will present our Gemini/GNIRS observations of the high (R~18000) resolution, near-infrared H3+ and H2 auroral emission maps in Jupiter's polar regions. These can be used to estimate temperatures and ion density profiles in upper ionosphere of the planet. In combination with Juno's measurements of particle energies in planetary magnetospheres, infrared emissions describe how the ionosphere of the planet responds to heating. 

P19: Measuring the Extragalactic Background Light via WAVES Input Catalogue
Soheil KOUSHAN, international Centre for radio Astronomy Research

Extragalactic background light (EBL) is energy from any source over the full pathlength of the universe with emission between 0.1 micron and 1000 micron. The EBL from UV to FIR from star formation within normal galaxies is likely to be the dominant radiant energy in the universe aside from the Cosmic Microwave Background (CMB) (Hauser and Dwek, 2001). In general, EBL comprises the integrated light from resolved and unresolved extragalactic sources. This light comes from any truly diffuse background excluding CMB. Mainly, this research measures the discrete components in the universe i.e. galaxies using the input catalogue for the Wide Area and Vista Extragalactic Survey (WAVES ) (Driver et al. 2015) in preparation for the WAVES-Wide and WAVES-Deep spectroscopic campaign on 4MOST. Additionally, this work will use the WAVES input catalogue to calculate galaxy number counts in 9 bandpasses (0.4 - 2.1 ) and model the extragalactic background light contribution from resolved extragalactic sources. It is worth noting that it is intermediate magnitude galaxy number-counts such as these which dominate the overall EBL. This measurement does not contain any diffuse components. So the comparison between this work and the total EBL from Very High Energy Astrophysics (VHEA) experiments represents the amount of diffuse sources in the universe. Generally, VHEA investigate the strong residual emission, which is emanating from distant blazars, a subgroup of galaxies hosting active galactic nuclei (AGN). These high-energy photons are attenuated by photon-photon interaction with the EBL passing through the universe. At the moment the uncertainty between these two methods are about 20% and the dominant part of this error is back to the cosmic variance estimates. However, having wide and deep data set are essential to reduce this error component. As a consequence, I am applying WAVES data set covering 1100 of the galactic sky. Using the WAVES catalogue, I am hoping to reduce this error down to 5% by the end of this research.

P20: Introducing ADACS - Astronomy focused expert training, data services and computing infrastructure
Rebecca LANGE, Curtin Institute for Computation

 Introducing ADACS - Astronomy focused expert training, data services and computing infrastructure

P21: Disentangling the dense gas towards the TeV gamma-ray source HESS J1745-303
James LAU, University of Adelaide

The TeV emission from HESS J1745-303 has been linked to hadronic emission from cosmic-rays accelerated from SNR G359.1-0.5. Mopra observations of numerous molecular species have traced shocked gas outside the SNR radio boundary and several other SNRs are seen in the region. This complex region is towards the Central molecular zone, and so multiwavelength data has been used to disentangle the gas features and provide insight into the nature of the TeV gamma-ray emission.

P22: Studies of the interstellar medium towards the unidentified TeV gamma-ray sources HESS J1614-518 & HESS J1616-508
James LAU, University of Adelaide

Although many Galactic TeV gamma-ray sources have been associated with high-energy phenomena, the nature of a significant number of these sources remains unknown, as they have no clear counterparts at other wavelengths. To unravel these sources, detailed understanding of the distribution of the interstellar medium (ISM) is required, as ambient gas may provide target material for accelerated cosmic-rays to generate TeV gamma-rays via proton-proton iterations. Two unassociated sources are HESS J1614-518 and HESS J1616-508. In order to investigate the ISM towards these sources, we have used data from a 7mm wavelength study using the Mopra Radio Telescope, as well as data from the Mopra Southern Galactic Plane CO Survey and the Millimetre Astronomer's Legacy Team - 45 GHz survey, and present our findings here.

P23: The SNRs towards the LMC: The multiwavelength era
James LAU, University of Adelaide

We live in an exciting era for the detection of extra-galactic supernova remnants (SNRs). The increased angular resolution and sensitivity of radio observations (ASKAP, ATCA, MWA) combined with X-ray (XMM and Chandra), IR (Herschel and Spitzer) and optical (WIFES) images have unveiled a total of over a hundred SNRs and SNR candidates towards nearby galaxies. Recently, the most complete Sigma-D study of magellanic cloud SNRs has been produced. The identification of significant and unexpected differences among some of these SNRs has also been shown. In this poster, we review the most recent progress of our multiwavelength study towards the Large Magellanic Cloud (LMC). We first display our polarisation study towards various SNRs. Additionally, for most of our studied SNRs in the LMC, carbon monoxide CO surveys have revealed molecular clouds (MCs) with good spatial correspondence to the thermal and non thermal X-rays, suggesting potential SNR-MC interaction. We highlight several embedded dense clumps which could provide sufficient target material for cosmic-rays (CRs) to produce significant gamma-ray emission. These emission may, in fact, be detected by the upcoming ground-based gamma-ray telescope CTA. These results will provide important information about the interaction between SNRs and their surrounding environment.

P24: The first OzDES Data Release
Chris LIDMAN, Australian Astronomical Observatory

We present the first data release from OzDES, a six-year programme to obtain redshifts for objects in the Dark Energy Survey (DES) supernova fields with the 2dF fibre positioner and AAOmega spectrograph on the Anglo-Australian Telescope. We present the observing strategies and data reduction methods that enable us to obtain a 90% redshift completeness for sources as faint as r=24, which traditionally has been beyond the reach of fibre fed spectrographs on 4-m class telescopes. We also describe our approach for calibrating the relative and absolute flux scales of AAOmega spectra, which is critical for measuring time lags in AGN.

P25: IFU Mosaic of Intermediate Stage Merger Galaxy ESO202-G23
Fergus LONGBOTTOM, Australian National University

As asserted by Rifatto et al (2001), ESO202-G23 (also known as “The Carafe”) is thought to be intermediate stage of a merger event that began some 106-109 years ago. The key evidence for this conclusion is the presence of tails and plumes in the galaxy’s outer regions and the double U shape of the Galaxy’s rotation curve derived using long slit spectroscopy, indicating the presence of two nuclei. Since then ESO202-G23 has been observed as part of the ANU Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) project (Dopita et al. 2015) using the ANU Wide Field Spectrograph (WiFeS) instrument on the 2.3m telescope at Siding Springs observatory and with the Australian Telescope Compact Array (ATCA). The presence of two compact radio sources at 5GHz and 9GHz with steep spectral indices supports the notion that the two nuclei identified by Riffato et al (2001) are in fact the super massive blackholes of the two precursor galaxies that collided. The S7 data indicated a LINER type spectrum for the brighter of the two nuclei but was inconclusive in regards to the second dimmer nucleus. The original WiFeS observations as part of S7 covered a 0.26 square arcminute field of view with a total exposure time of 40 minutes (Thomas et al 2017). In this poster, I will present a new WiFeS mosaic of this system, covering a 2.3 square arcminute field of view to a greater depth than the previous observation. This mosaic, complemented by the ATCA radio continuum data, will give insight into the gas kinematics surrounding the two nuclei as well as the nature of the ionisation driving the emission detected from the nuclei.

P26: Understanding the Progenitors behind DES16X3bdj and DES16C2ayx
Nataliea LOWSON, Australian National University

Peculiar transits are becoming more common in surveys, changing our perception on what is considered extreme stellar evolution. Using the Dark Energy Survey (DES) and the Australian Dark Energy Survey (OzDES), we have identified DES16X3bdj and DES16C2ayx, two objects that are exhibiting unusual features. DES16X3bdj shows no signs of H-alpha emission but has a strong presence of Silicon, indicating type Ib/Ic supernova classification but the eject of material is moving at a faster rate than what is normally observed. Its light curve is also unique and could be the result of circumstellar material or a shock break out. If its the latter then this would be the first observation for such a supernova, as this type of event has been theorised to be the progenitor of Gamma-Ray Bursts (GRBs). Our second object, DES16C2ayx, has features that indicates a very large and powerful explosion (ejecta is moving at ~28,000 km/s) but has not been changing at the same rate as other supernova of similar magnitudes. Its spectra also contains large quantities of blue light indicating that this is an type II supernova event. Through intense spectral analysis and cross correlation to previously classified events we are attempting to understand the physics behind each event and determine their progenitors.

P27: WISE J0808-6443: A 45 Myr-old accreting M-dwarf hosting a pre-transitional disc
Simon MURPHY, University of New South Wales Canberra

WISE J080822.18$-$644357.3 was recently identified by citizen scientists in the NASA Disk Detective project as a new M dwarf debris disc system and a candidate member of the 45 Myr-old Carina association. Given that the strength of its infrared excess ($L_{ir} \sim 0.1 L_{bol}$) appears to be more consistent with a young protoplanetary disc, we present the first optical spectra of the star and reassess its evolutionary and membership status. The spectroscopic and photometric data are consistent with WISE J0808-6443 being a $\sim$0.1 $M_{\odot}$ Classical T-Tauri star hosting a pre-transitional disc and one of the oldest known accreting M-type stars. These results suggest that the upper limit on the lifetimes of gas-rich discs around the lowest mass stars may be longer than previously recognised, or some mechanism may be responsible for regenerating short-lived discs at later stages of pre-main sequence evolution.

P29: Calibrating the POLARBEAR experiment - A quest of B-mode Polarisation
Anh T.P. PHAM, The University of Melbourne

Polarisation of the cosmic microwave background (CMB) provides a unique probe of primordial gravitational waves from cosmic inflation on degree scales, and of the growth of large scale structure (through gravitational lensing) on sub-degree scales. POLARBEAR is a ground-based experiment located in the Atacama Desert of Northern Chile. Polarbear’s primary goal is to search for the curl-like component called B-modes in the CMB polarisation pattern, which would be the first evidence for primordial gravitational waves from cosmic inflation. POLARBEAR collects data by measuring the electrical current through each polarisation-sensitive detector. Naturally, these current measurements must then be converted in temperature units for the purpose of making maps of the CMB anisotropy and calculating the CMB power spectra. I will present the calibration method for the POLARBEAR data, which uses a combination of observations of a local, rotating stimulator and planets.

P30: The Distribution of Mass in Early-Type Galaxies
Adriano POCI, Macquarie University

 

The total-mass profile of galaxies has recently emerged as an important property for constraining models of galaxy structure and formation. Accurately determining this profile is not trivial, and pushes the limits of systematic errors in the analysis of stellar dynamics, stellar populations, gravitational lensing, and simulations, as it involves uncertain fundamental properties such as dark matter content, and IMF, among others. I present a novel technique for constraining these properties with dynamical models of early-type galaxies (ETGs) with integral-field spectroscopy, while accounting for spatial gradients in stellar age and metallicity (as shown in Poci et al., 2017). I measure the total-mass profile slope for a large sample of ETGs, and compare with predictions from cosmological simulations. I conclude with new results of this technique applied to state-of-the-art MUSE observations from the new Fornax3D survey

P31: Pluto and Charon: formation by binary fission
Andrew PRENTICE, School of Physics & Astronomy, Monash University; Astrophysics Group, U. of Southern Queensland

The ratio F of the mass of Pluto (P) to Charon (C), viz. F ~ 8.2:1, is the largest mass ratio of any planet-satellite pair in the Solar system. Another measure of the PC binary is its normalized angular momentum density J (see McKinnon 1989). An analysis of astrometric data (Brozovic et al 2015) acquired before the arrival of New Horizons (NH) and new measurements made by NH (Stern et al 2015) show that J = 0.39. Yet these F and J are the very ones expected if the PC binary had formed by the rotational fission of a single liquid mass (Darwin 1902). At first glance, therefore, the fission model seems to be a viable model for the formation of the Pluto system. In fact, Prentice (1993 Aust J Astron 5 111) had used this model to successfully predict the existence of several other moons orbiting beyond Charon, before their discovery in 2005-2012. The main problem with the fission model is that the observed mean density of Charon, namely 1.70 g/cc, greatly exceeds that of water ice. Charon thus could not have once been a globe of pure water. Here I review the fission model within the framework of the modern Laplacian theory of solar system origin (Prentice 1978 Moon Planets 19 341; 2006 PASA 23 1) and the NH results. I assume that Pluto and Charon were initially a single object (proto-Pluto [p-P]) which had condensed within the same gas ring shed by the proto-solar cloud at orbital distance ~43 AU, where the Kuiper belt was born. The temperature of this gas ring is 26 K and the mean orbit pressure is 1.3 x 10^(-9) bar. After the gas ring is shed, chemical condensation takes place. The bulk chemical composition of the condensate is anhydrous rock (mass fraction 0.5255), graphite (0.0163), water ice (0.1858), CO2 ice (0.2211) and methane ice (0.0513). Next I assume that melting of the ices in p-P takes place through the decay of short-lived radioactive nuclides, thus causing internal segregation of the rock & graphite. This triggers rotational fission. Pluto’s moons would then form from liquid water and liquid CO2, as well as entrained rock-graphite particles. Charon’s mean density implies that the rock-graphite mass fraction of the fissioned mass was ~0.41. The outer mantle of Pluto (mass fraction 0.0575 and thickness 88 km) is predicted to consist of pure methane ice.

P32: Polarimetry With ASKAP
Wasim RAJA, CSIRO

ASKAP is a test-bed for several new technologies for future radio telescopes. While the Phased Array Feed (PAF) at the focal plane of each ASKAP dish makes wide-field imaging possible, the unique 3rd axis (or "roll axis") of the dish allows the dish's response to remain fixed with respect to celestial coordinates, greatly improving our ability to precisely calibrate images and achieve high-dynamic-range imaging. Both aspects have now been well demonstrated for Stokes-I imaging. The PAFs and the roll axis also provide a unique avenue for obtaining high-fidelity polarisation imaging over a wide field. We present here ASKAP images, in full polarisation, of a test field towards the Fornax constellation one that has been well-studied with the Australia Telescope Compact Array (ATCA). We discuss our calibration method that makes use of the roll-axis, and compare our results with data from the ATCA as well as the NVSS. We highlight the challenges in polarisation calibration and outline several promising approaches to dealing with these challenges, notably those involving the On-Dish Calibration system, and advanced beam-forming techniques.

P33: AAO Data Central: a 3V (Variety, Volume, Velocity) Data Centre
Katrina SEALEY, AAO

We present AAO Data Central, a 3V astronomical data archive using Apache Hadoop that incorporates a RESTful API, a web-based interface for simple access and querying and a TAP service. Hadoop allows us to query data using SQL syntax, however the underlying system uses an object oriented data model to manage heterogeneous datasets, rather than a more traditional relational model. AAO Data Central currently hosts the SAMI Survey Data Release 1 and the GAMA survey Data Release 2, with AAT and UKST surveys of national significance eventually being hosted in the system. We will discuss the technical details and future developments of our system.

P34: Numerical simulations of intermittent radio jets from Active Galactic Nuclei
Stas SHABALA, University of Tasmania

Authors: Patrick Yates, Stas Shabala, Martin Krause. Feedback from Active Galactic Nuclei on the host environment is required to maintain the delicate heating/cooling balance in massive galaxies over the latter half of the Hubble time. The process usually invoked is kinetic feedback from radio jets, which do work on their host hot atmospheres through supersonic outflows, shocks and gas uplifting. An open question is whether the efficiency of this feedback mode depends on jet intermittency. We investigate the energetic and morphological effects of different environments and jet intermittency. We present numerical hydrodynamic simulations of radio jets using the PLUTO simulation code. These radio jets were simulated in both cluster and poor group environments. In each simulation, the same total energy is injected at the same time-averaged rate (i.e. using the same average jet power), but using a different number of jet episodes. We quantify the fraction of injected energy that couples to the surrounding gas, and compared AGN feedback efficiencies in different energy injection scenarios.

P35: Radio AGN Photometric Redshifts and Standard Candles
Stas SHABALA, University of Tasmania

Authors: Ross Turner, Stas Shabala, Nick Seymour, Guillaume Drouart. Immensely bright quasars and radio-loud active galactic nuclei (AGN) provide an opportunity to construct standard candles detectable up to the very early universe. We present a new technique for creating standardisable candles from radio observations of the very-large synchrotron emission lobes inflated by the most powerful AGN; specifically our method uses radio flux, lobe angular size, and the radio SED spectral index and break frequency. This technique is used to measure the distance to radio sources in the 3C and HeRGE surveys, providing redshift coverage from z = 0.05 up to 4.5, and enabling us tightly constrain the matter and dark energy densities. We further show that our distance measure provides reliable photometric redshifts for radio-AGN based exclusively upon multi-frequency radio observations. This technique may provide a viable redshift measurement in future radio surveys (such as EMU) which have limited spectroscopy.

P36: DEVELOPMENT OF X-RAY FOCUSING MIRRORS AT MSFC
Dharma SHARMA, NASA/MSFC

The revolutionary leap in X-ray astronomy has been achieved after high special resolution X-ray telescopes utilizing grazing incidence have been flown onboard a number satellites. The progress in astronomy achieved by such telescopes is unparalleled giving insight in to various astrophysical processes, for example, grazing incidence telescopes onboard Chandra continue to provide new revelations in X-ray astronomy. At Marshall Space Flight Center (MSFC) a dedicated program is ongoing to produce improved focusing grazing incidence optics for approved and future missions. A snapshot of these developments will be provided in this poster.

P37: Pulsating A-type stars in binary systems
Margaret STREAMER, Research School of Astronomy and Astrophysics

A-type stars span the transition area of energy transport between stars with a radiative core and a deep convective envelope (M < 1.3M) and those with a small convective core and deep radiative envelopes (M > 2M). A-stars evolving off the main sequence can exhibit δ Sct-type pulsations which present an opportunity to determine the internal structure and evolutionary state of these stars. Accurate asteroseismology of A-stars remains elusive, due to difficulty in mode identification. We are undertaking a program of detailed study of δ Sct stars in eclipsing binary systems, where the absolute mass and radius of the components can be determined with confidence using a combination of photometric and spectroscopic techniques, and the pulsating component is likely tidally locked.  We  focus on one such system, TT Horologium, where we have an accurate radial velocity orbit, masses with ~5% uncertainty, have modelled the interior structure with MESA and have preliminary mode identification.

P38: Citizen Science with SkyMapper
Brad TUCKER, ANU

We will give an overview of two recent citizen science projects using SkyMapper - the Seach for Planet 9, and Supernova Sighting.  We will take about the reasons, successes, and opportunites for all projects to benefit from citizen scientists.

P39: Radio Galaxy Zoo: current status and science results
Julie BANFIELD, Australian National University

 

Radio Galaxy Zoo is an online citizen science project designed to cross-identify radio sources with their host galaxy.  Radio Galaxy Zoo was launched on December 17, 2013. This poster will update the astronomical community on the science impact of Radio Galaxy Zoo including current outcomes, volunteer statistics, and outreach programs.