Cosmic collision gives birth to new astronomy field

Tuesday, 17 October 2017

Cosmic collision gives birth to new astronomy fieldScientists collaborating around the world, including at the University of Adelaide, have for the first time ever observed a cosmic event by both gravitational waves (or ripples in space and time) and, the more conventional, light.

The Laser Interferometer Gravitational-Wave Observatory (LIGO)-Virgo Collaboration, which less than two years ago rocked the science world with the announcement of its first ever detection of gravitational waves from merging black holes, has detected gravitational waves from a spectacular collision of two neutron stars. Neutron stars are the smallest, densest stars known to exist and are formed when massive stars explode in supernovas.

When these neutron stars spiraled together about 130 million years ago, they emitted gravitational waves. The two LIGO detectors at Hanford, Washington and Livingston, Louisiana in the US detected waves emitted during the last 100 seconds of the death spiral on Thursday 17 August 2017 at 8.41 am US Eastern Daylight Time. Information from the Virgo detector in Europe was used to dramatically improve the localisation of the source in the sky.

About two seconds after the end of the burst of gravitational waves, a pulse of light in the form of gamma rays from the same sky location was observed by the Gamma-ray Burst Monitor on NASA’s Fermi space telescope.

In the days and weeks following the collision, other forms of light, or electromagnetic radiation — including X-ray, ultraviolet, optical, infrared, and radio waves — were detected by ground and space-based observatories around the world.

“Before this first-ever detection of a binary neutron-star merger, electromagnetic telescopes could see the gamma rays emitted by a merger but didn't know what caused it,” says Professor Peter Veitch, University of Adelaide’s Head of Physics and Node-Leader of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), and a member of the LIGO Scientific Collaboration.

“When the LIGO-Virgo collaboration made the landmark detection of gravitational waves, we could identify the source of the gravitational waves but only knew approximately the location. Now we know both what happened and where it happened – multi-messenger gravitational astronomy has been born.”

The LIGO-Virgo results are published today in the journal Physical Review Letters, and additional papers from this group and the astronomical community are being published in other journals including Science and Nature.

“We’ve now seen the first event using multi-messenger gravitational astronomy but with improved sensitivity we can observe many more of these cosmic events,” says Associate Professor David Ottaway, OzGrav Chief Investigator, University of Adelaide.

“With more observations, we will be able to build a clear picture of the evolution of our stars and galaxies and the birth and development of the Universe. Here at the University of Adelaide we are working with LIGO and OzGrav colleagues to improve the sensitivity of the current detectors, and we’re developing the technology for the next generation of detectors.”

Background

LIGO is funded by the NSF, and operated by Caltech and MIT, which conceived of LIGO and led the Initial and Advanced LIGO projects. Financial support for the Advanced LIGO project was led by the NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project. More than 1,200 scientists and some 100 institutions from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration and the Australian collaboration OzGrav. Additional partners are listed at http://ligo.org/partners.php

The Virgo collaboration consists of more than 280 physicists and engineers belonging to 20 different European research groups: six from Centre National de la Recherche Scientifique (CNRS) in France; eight from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; two in the Netherlands with Nikhef; the MTA Wigner RCP in Hungary; the POLGRAW group in Poland; Spain with the University of Valencia; and the European Gravitational Observatory, EGO, the laboratory hosting the Virgo detector near Pisa in Italy, funded by CNRS, INFN, and Nikhef.

The ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) is funded by the Australian Government through the Australian Research Council Centres of Excellence funding scheme. OzGrav is a partnership between Swinburne University of Technology (host of OzGrav headquarters), the Australian National University, Monash University, University of Adelaide, University of Melbourne, and University of Western Australia, along with other collaborating organisations in Australia and overseas.

 

Contact Details

Professor Peter Veitch
Email: peter.veitch@adelaide.edu.au
Website: http://www.adelaide.edu.au/directory/peter.veitch
Head of Physics
School of Physical Sciences
The University of Adelaide
Mobile: +61 (0)422 906 827


Associate Professor David Ottaway
Email: david.ottaway@adelaide.edu.au
School of Physical Sciences
Institute for Photonics and Advanced Sensing
The University of Adelaide
Business: +61 8 8313 5165
Mobile: +61 0430 325 099


Ms Robyn Mills
Email: robyn.mills@adelaide.edu.au
Media and Communications Officer
The University of Adelaide
Business: +61 8 8313 6341
Mobile: +61 410 689 084