Overview of Research Areas Institute of Astronomy
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1 Overview of Research Areas Institute of Astronomy Name Room Phone email Prof Tim Bedding 554 9351 2680 [email protected] Dr Hans Bruntt 565 9351 3041 [email protected] Dr Julia Bryant 563 9351 2152 [email protected] Prof Iver Cairns 457 9351 3961 [email protected] Dr Shami Chatterjee 570 9351 5577 [email protected] Dr Scott Croom 561A 9036 5311 [email protected] Prof Bryan Gaensler 556 9351 6053 [email protected] A/Prof Anne Green 564 9351 2727 [email protected] Dr Andrew Hopkins 569 9351 7688 [email protected] Prof Dick Hunstead 567 9351 3871 [email protected] Dr Helen Johnston 563 9351 2152 [email protected] Dr Lucyna Kedziora-Chudczer 323 9351 6080 [email protected] Dr Laszlo Kiss 561 9351 4058 [email protected] Dr Zdenka Kuncic 464 9351 3162 [email protected] A/Prof Geraint Lewis 557 9351 5184 gfl@physics.usyd.edu.au Dr Qinghuan Luo 318 9351 2546 [email protected] Prof Don Melrose 454 9351 4234 [email protected] Dr Tara Murphy 565 9351 3041 [email protected] Dr Stephen Ng 570 9351 5577 [email protected] Dr John O'Byrne 568 9351 3184 [email protected] Dr Gordon Robertson 562 9351 2825 [email protected] Prof Elaine Sadler 555 9351 2622 [email protected] Dr Dennis Stello 560A 9036 5108 [email protected] Dr Peter Tuthill 566 9351 3679 [email protected] Dr Mike Wheatland 463 9351 5965 [email protected] Research in the Institute of Astronomy is grouped in two main areas, Observational Astrophysics and Computational and Theoretical Astrophysics. Observational data are obtained from various facilities in Australia and overseas, as well as observatories in orbit. In addition to the national facilities — the Anglo-Australian Telescope and the Australia Telescope — the School operates its own radio telescope, the Molonglo Observatory Synthesis Telescope (MOST), while the Sydney University Stellar Interferometer (SUSI) is the major element in a broad program of high resolution optical imaging. Research is conducted in many exciting areas over a wide range of wavelengths, including solar and stellar astrophysics, asteroseismology, black-hole binary systems, masers, pulsars, supernovae and their remnants, the interstellar medium and the Galactic centre. Beyond our Galaxy, topics include normal galaxies, the Magellanic Clouds, clusters of galaxies, active galaxies and quasars. Computational and theoretical studies delve into areas of astrophysics that can only be addressed through analytical techniques, computer modelling, or numerical simulation. These include black-hole accretion, interstellar scintillation, planetary and solar emission, pulsar and magnetar radiation mechanisms, gravitational lensing, dark matter, general rela- tivity, and cosmology. Honours projects – Observational Astrophysics 2 Research Projects in the Institute of Astronomy Observational Astrophysics Magnets, electrons and supermassive black holes Supervisors: Prof Bryan Gaensler, Dr Ilana Feain (CSIRO ATNF) Contact: Bryan Gaensler, 556, [email protected], 9351 6053 The galaxy Centaurus A hosts the nearest known supermassive black hole to the Milky Way. This black hole is extremely energetic, as evidenced by powerful jets of radio emission that emerge from the galaxy at close to the speed of light, and which extend more than three million light years into intergalactic space. The radio emission from the jets of Centaurus A cover more than 30 square degrees. This means that there are thousands of background radio sources (mainly active galaxies and quasars) that sit behind Centaurus A. The radio emission from many of these sources should be linearly polarised, but this emission will be depolarised as it passes through the small- scale magnetic fields and turbulent electron gas in the radio lobes of Centaurus A. In this project, a student will find and catalogue all the polarised galaxies behind Centaurus A, and will correlate the degree of polarisation of these objects against the foreground structures seen in Centaurus A. These data will then be used to will provide the most detailed and direct study ever made of the magnetic fields and ionised gas ejected from massive black holes. The data required for this Honours project already exist, but there should be opportunities to participate in further radio observations of Centaurus A at the Australia Telescope Compact Array in early 2008. Intergalactic magnetism in the Phoenix Deep Field Supervisors: Prof Bryan Gaensler, Dr Andrew Hopkins, Dr Ray Norris (CSIRO ATNF) Contact: Bryan Gaensler, 556, [email protected], 9351 6053 Understanding the Universe is impossible without understanding magnetic fields. But in spite of their importance, the origin of magnetic fields is still an open problem. Did significant primordial fields exist before the first stars and galaxies? If not, when and how were magnetic fields subsequently generated? What maintains the present-day magnetic fields of galaxies, stars and planets? Fundamental to all these issues is the search for magnetic fields in intergalactic space. Such a field has not yet been detected, but its role as the likely seed from which all magnetic fields in galaxies and in galaxy clusters have originated places considerable importance on its discovery. In this project, a student will use data from the “Phoenix Deep Field” to search for magnetic fields in the intergalactic medium (IGM). The Phoenix Deep Field is one of the most sensitive radio astronomy observations of the sky ever carried out. While the radio-emitting sources in this area have already been thoroughly analysed, a topic which is totally unex- plored is the linear polarisation from these faint objects. Any intervening magnetic field in the IGM will induce Faraday rotation in this polarised light, and more distant sources should have higher levels of Faraday rotation. This project will involve identification of the polarised sources in the Phoenix Deep Field and the measurement of their Faraday rotation. With these data, we will be able either to finally detect intergalactic magnetism, or put a strong upper limit on its presence. Gas in the Galaxy: a three-dimensional study of hydrogen in the Milky Way Supervisors: Prof Bryan Gaensler, Dr Naomi McClure-Griffiths (CSIRO ATNF) Contact: Bryan Gaensler, 556, [email protected], 9351 6053 The “empty” space between the stars of the Milky Way is anything but. We now know that much of the mass of our Galaxy is distributed in a very low density interstellar medium (ISM), and that this rarefied, invisible gas is the fuel from which new stars are continually being formed. Much of the gas in the Milky Way is atomic hydrogen, but curiously, this gas appears to be split up into two separate phases: hot gas, with a temperature of about 6000 kelvin, and cold gas, at a temperature of just 100 kelvin. We generally expect that cold gas should be continually heated up (e.g., via shock waves from exploding stars) and that hot gas should cool down (e.g., on its way to collapsing into dense clouds that form new stars). However, the detailed relation (if any) between the hot and cold phases of the ISM remains unclear. This project will focus on an analysis of a spectacular new set of data on the ISM, made possible via the recently com- pleted International Galactic Plane Survey. Using the radio signal emitted by hydrogen gas at a frequency of 1420 MHz, a student will derive the three-dimensional distributions of both hot and cold gas in the ISM, and will use the similarities and differences between these distributions to better understand the life cycle and ultimate fate of gas in the Milky Way. Honours projects – Observational Astrophysics 3 Understanding the most rapidly rotating stars in the universe Supervisors: Prof Bryan Gaensler, Dr George Hobbs (CSIRO ATNF) Contact: Bryan Gaensler, 556, [email protected], 9351 6053 Pulsars are ultra-dense, rapidly rotating neutron stars. Their extreme rotational stability makes them amongst the most accurate clocks in existence. For the last three years, the Parkes radio telescope has been making a focused study of twenty pulsars that are especially stable and extremely rapid (more than 200 times per second) rotators. The eventual goal of these observations is to see very slight deviations in the clock accuracies produced by distortions in space-time, and thus make the first direct detection of gravitational waves (as predicted by Einstein's Theory of General Relativity). In this project, a student will lay the foundations for this overall experiment by determining the detailed properties of each of the twenty pulsars in the sample. Some of the parameters that need to be determined before we can detect gravitational waves include the exact position, distance and velocity of each pulsar; the presence or absence of planets in orbit around each pulsar; slight intrinsic irregularities in the pulsar spins; and long-term variability in the shape of the pulses from each star. This work will be done in close association with the Parkes Pulsar Timing Array team. There will the opportunity to help carry out some of the on-going observations of these pulsars using the “The Dish” at Parkes. The student will be expected to undertake some of their research work at the Australia Telescope National Facility headquarters in Epping. X-ray observations of an expanding supernova remnant and its high-speed neutron star Supervisors: Dr Shami Chatterjee and Prof Bryan Gaensler Contact: Shami Chatterjee, 570, [email protected], 9351 5577 Massive stars end their lives in spectacular supernova explosions. The outer layers of the star are blasted off into space, forming a supernova remnant.