UK scientists begin hunt for major collisions in the universe
2 Dec 2016 02:54 PM
UK scientists are celebrating the restart of the LIGO gravitational wave detectors, which are now back online after a substantial upgrade to their sensitivity. The upgrade and restart of LIGO means that the new data being produced should add substantially to our knowledge of black-hole collisions and other major astronomical events.
The Laser Interferometer Gravitational-wave Observatory (LIGO) proved the existance of gravitational waves earlier in 2016 and has now resumed the search for these ripples in the fabric of space and time allowing the many UK researchers working on the project to build on their understanding of how the universe works.
Speaking of the restart Professor Sheila Rowan, Director of the University of Glasgow’s Institute for Gravitational Research, and a member of the LIGO discovery team said
"We're very excited about not only the possibility of more black hole collisions -using this unique capability to build our knowledge of the black hole family tree- but also perhaps sensing neutron star collisions for the first time - new sources and new science from gravitational waves."
The improved sensitivity and longer observing period of LIGO should mean that more black-hole mergers will be observed in the coming run adding to our knowledge of black-hole dynamics. The Livingston detector now has about a 25 percent greater sensitivity—or range for detecting gravitational waves from binary black holes—than during the first observing run. That means it can see black-hole mergers at further distances than before, and therefore should see more mergers than before. The sensitivity for the Hanford detector is similar to that of the first observing run.
LIGO transitioned from engineering test runs to science observations at 8 a.m. Pacific Standard Time on November 30 and this new on-going study of gravitational waves is expected to provide important insights into the evolution of stars, supernovae, gamma-ray bursts, neutron stars and black holes.
The LIGO Scientific Collaboration comprises over 1000 scientists from 17 countries, and includes researchers from ten UK universities (Glasgow, Birmingham, Cardiff, Strathclyde, West of Scotland, Sheffield, Edinburgh, Cambridge, King College London and Southampton).
Jake Gilmore STFC Media Manager
LIGO was designed and is operated by Caltech and MIT, with funding from the National Science Foundation (NSF). Advanced LIGO is funded by the NSF with important contributions from the UK Science and Technology Facilities Council (STFC), the Max Planck Society of Germany, and the Australian Research Council (ARC).
LIGO consists of two L-shaped interferometers, one in Hanford, Washington, and one in Livingston, Louisiana. Each arm of each L is 2½ miles (4 km) long. Lasers look for changes in each arm's length as small as a millionth the diameter of a proton. Passing gravitational waves might distort space-time by that much.
On February 11, 2016, the LIGO Scientific Collaboration (LSC) and the Virgo Collaboration announced that LIGO had made the first-ever direct observation of gravitational waves. The waves were generated by a tremendously powerful collision of two black holes 1.3 billion light-years away and were recorded by both of LIGO's detectors—one in Hanford, Washington, and the other in Livingston, Louisiana. A second gravitational-wave detection by LIGO was announced on June 15, 2016, also from merging black holes.
The initial detections were made during LIGO's first run after undergoing major technical upgrades in a program called Advanced LIGO. That run lasted from September 2015 to January 2016. Since then, engineers and scientists have been evaluating LIGO's performance and making improvements to its lasers, electronics, and optics—resulting in an overall increase in LIGO's sensitivity.
Independent and widely separated observatories are necessary to verify the direction of the event causing the gravitational waves, and also to determine that the signals come from space and are not from some other local phenomenon.