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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2008 Colloquia
The high stability of some millisecond pulsars (MSPs), along with ever increasing levels of timing precision, has been predicted to enable detection of gravitational wave (GW) effects on the Earth. Specifically, it has been shown that GWs arising from hierarchical galaxy formation - and associated supermassive black hole binaries - would be detected provided 20 MSPs can be timed for five years or more at a precision of ~100 ns. The practical feasibility of this scenario is investigated.
We present results from a long-term timing campaign at the Parkes radio observatory, for the first time providing insights into the timing stability of a large number of MSPs (20). On one of our sources we obtain 200 ns timing precision, which is a first over timescales of a decade or more. More than half of our sample displays stability at current levels of timing precision and a simple analysis on some of our brightest sources demonstrates the potential for sub-100 ns timing.
Using these results, we evaluate the potential for timing array efforts on the major radio telescopes of the world and are cautiously optimistic about the potential for a GW detection within the coming decade.
Based on a new study of pulsar spin-down irregularities and previous observations of an unusual, intermittent pulsar, PSR B1931+24, I present a model for pulsar timing noise. Our model links many pulsar phenomena including moding, nulling, intermittency, pulse shape variability and timing noise. Our model shows that the timing residuals for PSR B1828-11 and its pulse shape variations can be explained, suggesting that this pulsar is not undergoing free precession as previously thought. The ability to model and, hence, remove the timing irregularities leads to the possibility of forming a perfectly stable pulsar clock that could be used to improve tests of general relativity, to search for the elusive gravitational waves and to produce a pulsar-based timescale that, over long time scales, will be competitive with existing terrestrial time scales. In my talk I will describe observations of pulsars over many decades, explain the new model and discuss its implications
The twin Keck 10-metre telescopes on the summit of Mauna Kea in Hawaii have been the largest optical telescopes in the world for more than the last decade. They have been at the forefront of astronomical discovery, through their unrivaled observations of planets around other stars to galaxies seen billions of years back in time.
In this talk, Dr Taft Armandroff, the Director of the Keck Observatory, will look to these powerful telescopes' future, describing the exciting new discoveries they are poised to make in the next decade and beyond.
Location AGSE 207 (AGSE Building Cnr Wakefield and William Streets, Hawthorn). For further information or to reserve a seat: email contact@astro.swin.edu.au or contact Carolyn Cliff on 9214 5569.
The lecture is free, but as seating limited, please contact Carolyn Cliff 03 9214 5569 or ccliff@swin.edu.au to reserve a seat. Location: AR104
The lecture is free, but as seating limited, please contact Carolyn Cliff 03 9214 5569 or ccliff@swin.edu.au to reserve a seat. Location: AR104
We explore how light behaves near massive objects, and show that for gravitational lenses, gravitational redshifts and black holes, the main concepts can be understood in general terms from Einstein's oft-quoted equation, E=mc^2.
Light paths are changed as they pass close to the sun and to massive galaxies, so giving us the idea of gravitational lenses which can change the appearance of distant galaxies and quasars. Some examples of multiply imaged quasars and lensed galaxies are given.
Gravitational redshifts of light from compact stars have been measured. In the extreme case of very compact objects - black holes - no light can escape at all. There are compelling reasons for believing that massive black holes reside near the centers of many galaxies, and particularly the center of the Milky Way.
The lecture is free, but as seating limited, please contact Carolyn Cliff 03 9214 5569 or ccliff@swin.edu.au to reserve a seat.
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Development of a Software Back-end for the GMRT