University of Tasmania, Australia

Radio astronomy is the study of objects beyond the Earth's atmosphere using the light they emit in the radio band of the electromagnetic spectrum. The School of Mathematics and Physics is unique in Australia in possessing two world class radio telescopes, one at the Mt Pleasant Observatory near Hobart and the other near Ceduna in South Australia. The major research interests of the radio astronomy group are in :

• Active galactic nuclei
• Interstellar masers
• Pulsars

The School of Mathematics and Physics operates two radio astronomy observatories. One at Mt Pleasant approximately 20km from Hobart and the other near Ceduna in South Australia. There are two telescopes at the Mt Pleasant Observatory, a 26m general purpose telescope which was donated to the University by NASA in 1985 and a home-built 14m telescope which is dedicated to observations of the Vela pulsar. The Ceduna Observatory has a single 30m antenna which was donated to the University in 1995 by Telstra.

The primary research interests of the radio astronmers are in the following areas :

• The nuclei of active galaxies
• Interstellar masers
• Pulsars and supernova remenants

The University of Tasmania telescopes play a vital role in a number of Australian and international very long baseline interferometry (VLBI) arrays.

In conjunction with telescopes at Parkes, Coonabarabran and Narrabri in NSW operated by the CSIRO, the Mt Pleasant 26m and Ceduna 30m telescopes form the Australian VLBI network, which is operated as a national facilty by the CSIRO and University of Tasmania. The University of Tasmania antennas provide all the long baselines in this array and enable it to produce images with a resolution of less than 1 thousandth of an arcsecond (one hundred times smaller than the Hubble space telescope).

The telescopes also participate in world-wide VLBI arrays, collaborating with telescopes in South America, Africa and Antarctica. Data collected with the Mt Pleasant antenna has been used to measure the tectonic plate motion of continential plate which Tasmania sits on.

The Mt Pleasant and Ceduna telescopes also regularly participate in experiments with the Japanese VSOP (VLBI Space Observatory Platform) satellite. This is the first orbiting radio telescope and the high-resolution images which are made when it participates as a member of a VLBI array are challenging current models of the physics of blackholes.

The Mt Pleasant and Ceduna telescopes are also regularly used to make observations of interstellar masers. A maser (microwave amplification by stimulated emission of radiation) is the radio frequency equivalent of a laser. These arise naturally in space in a variety of locations, including in the gas around newly formed large stars, in the envelopes of old stars, at the edges of supernova remnants and in circumnuclear discs in active galaxies. The Mt Pleasant telescope has been used extensively to search for new masers and is responsible for discovering approximately one quarter of all methanol masers.

Pulsars form when a star five (5) or so times larger than the Sun runs out of fuel. The star implodes leaving a rapidly spinning neutron star (the densest material in the Universe) as the core. The time at which pulses of light from the spinning neutron star arrive at the Earth can be measured very accurately, but occasionally young pulsars such as the Vela pulsar "glitch".

Members (External)

Professor John Dickey, John.Dickey@utas.edu.au

Dr Simon Ellingsen, Simon.Ellingsen@utas.edu.au

Dr Jim Lovell, Jim.Lovell@utas.edu.au