Breakthrough! A new era begins in astronomy
17 October 2017
Twenty-five CAASTRO astronomers from eight institutions have contributed to a stunning breakthrough, announced today, that has brought gravitational-wave astronomy and conventional astronomy together.
“For the first time we’ve seen light and radio waves accompanying a burst of gravitational waves,” said the leader of CAASTRO’s Dynamic Universe theme, Associate Professor Tara Murphy of the University of Sydney.
On 17 August the Laser Interferometer Gravitational-wave Observatory (LIGO) in the USA and the Virgo detector in Italy picked up gravitational waves from an event dubbed GW170817, thought to be two neutron stars merging.
The LIGO-Virgo collaboration sent out an alert, triggering astronomers worldwide to train their telescopes on the sky.
Associate Professor Murphy roused her Australian team and asked for time on CSIRO’s Compact Array telescope, getting it almost immediately. The team began observing as soon as the target area of sky rose over Australia.
When a US optical telescope saw brightening in galaxy NGC 4993, Professor Murphy’s team zeroed in and detected radio waves.
NGC 4993 lies about 130 million light-years away, in the constellation of Hydra.
While the radio observations were getting under way, astronomers at CAASTRO’s Australian National University (ANU) node swung into action with the SkyMapper telescope at Siding Spring Observatory. In this short video, CAASTRO's ANU node leader, Christian Wolf, describes what they found when they imaged the source.
At the same time, the Australian Astronomical Observatory's Chris Lidman was using the 3.9-m Anglo-Australian Telescope, also at Siding Spring Observatory, to obtain spectra with the AAT's robotic optical fibre system, 2dF. Lidman was able to start observations just five minutes after the triggering alert came in, thanks to a new 'Target of Opportunity' system that works out the minimum number of optical fibres that need to be moved.
Reflecting on today's announcement, CAASTRO Director Professor Elaine Sadler (University of Sydney) said: “Just two years ago we were celebrating the first detection of gravitational waves – a truly historic occasion.”
“Today marks the start of another new era. Gravitational waves are now truly part of astronomy. They will be the key to understanding the Universe’s most powerful and distant events.”
“I congratulate everyone involved in this marvellous breakthrough.”
CAASTRO astronomers involved in these observations
Abbott, B.P., et al., "Multi-messenger observations of a binary neutron star merger," ApJL (2017) (in press)
Andreoni I., et al., “Follow up of GW170817 and its electromagnetic counterpart by Australian-led observing programs”, Publications of the Astronomical Society of Australia (2017) (submitted - preprint on arXiv).
Hallinan, G., et al., “A radio counterpart to a neutron star merger”, Science (2017)
Smartt, S.J., et al., "A kilonova as the electromagnetic counterpart to a gravitational-wave source", Nature (2017)
The ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) is a collaboration between The University of Sydney, The Australian National University, The University of Melbourne, Swinburne University of Technology, The University of Queensland, The University of Western Australia and Curtin University, the last two participating together as the International Centre for Radio Astronomy Research (ICRAR). CAASTRO is funded under the Australian Research Council (ARC) Centre of Excellence program, with additional funding from the seven participating universities and from the NSW State Government's Science Leveraging Fund.
Audio recording from AusSMC press conference with A/Prof Tara Murphy (3 min 23 sec; courtesy AusSMC)
Explainer article by A/Prof Tara Murphy in The Conversation
Helen Sim (Media assistance, CAASTRO)
Ph: +61 419 635 905 E: Helen.Sim@sydney.edu.au