Monash involved in second detection of gravitational waves
On Boxing Day 2015 at 03:38:53 UTC, three months after the first ever detection of gravitational waves from a merger of two black holes, ripples in the fabric of spacetime were detected for the second time by both of the twin Laser Interferometer Gravitational-Wave (LIGO) detectors in the USA.
The LIGO team concluded that these gravitational waves were produced approximately 1.4 billion years ago during the final moments of the merger of two black holes—14 and 8 times the mass of the sun—to produce a single, more massive spinning black hole 21 times the mass of the sun.
As with the first detection, a team of LIGO Scientific Collaboration (LSC) researchers at Monash University played an important role in the design and implementation of hardware and software components associated with the detection and interpretation of this gravitational wave, and also played a key role in interpreting the data from the detectors.
Dr Eric Thrane, who co-chairs one of LIGO’s four data analysis groups, explained the significance of this second detection.
“The first detection of gravitational waves in September last year marked a pivotal moment in the history of astronomy,” Dr Thrane said. “The fact that we have so quickly detected gravitational waves from a second pair of colliding black holes is very exciting as it suggests these events are more numerous than many researchers previously believed. We also anticipate that other sources of gravitational waves may be detected in the future as the detectors are made even more sensitive.”
Under the supervision of Dr Eric Thrane, Monash Science Honours student Chris Whittle has been investigating data analysis techniques for gravitational wave detection. Later in June Chris will travel to Washington, USA, to spend three months working with a team of LIGO scientists and engineers on improving the detector to make it even more sensitive to gravitational waves.
Chris described how it feels to be involved in such globally significant scientific research.
"I feel privileged and honoured to have been involved with the LIGO Scientific Collaboration as an undergraduate during such a momentous discovery as the first, and now second, detection of gravitational waves. I am thrilled to have been given the opportunity to work directly on the Hanford detector with the LIGO scientists and engineers in Washington and look forward to further exciting results from the detectors as they are made even more sensitive to these ripples in spacetime,” Chris said.
About LIGO and the second detection of gravitational waves
The LIGO Observatories are funded by the National Science Foundation (NSF), and were conceived, built, and are operated by Caltech and MIT. The discovery, accepted for publication in the journal Physical Review Letters, was made by the LIGO Scientific Collaboration (which includes the GEO Collaboration and the Australian Consortium for Interferometric Gravitational Astronomy, which includes Monash University) and the Virgo Collaboration using data from the two LIGO detectors.
“It is very significant that these black holes were much less massive than those observed in the first detection,” says Gabriela Gonzalez, LIGO Scientific Collaboration (LSC) spokesperson and Professor of Physics and Astronomy at Louisiana State University. “Because of their lighter masses compared to the first detection, they spent more time—about one second—in the sensitive band of the detectors. It is a promising start to mapping the populations of black holes in our universe.”
Both the first and second discoveries were made possible by the enhanced capabilities of Advanced LIGO, a major upgrade that increases the sensitivity of the instruments compared to the first generation LIGO detectors, enabling a large increase in the volume of the universe probed.
LIGO research is carried out by the LIGO Scientific Collaboration (LSC), a group of more than 1,000 scientists from universities around the United States and in 14 other countries. More than 90 universities and research institutes in the LSC develop detector technology and analyse data; approximately 250 students are strong contributing members of the collaboration. The LSC detector network includes the LIGO interferometers and the GEO600 detector.
The NSF leads in financial support for Advanced LIGO. Funding organizations in Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council, STFC) and Australia (Australian Research Council) also have made significant commitments to the project.