UK astrophysicists, including a team from the University of Birmingham, are gearing up to resume the search for gravitational waves, the ripples in space time caused by some of the universe’s most spectacular events.

The National Science Foundation's LIGO (Laser Interferometer Gravitational-Wave Observatory) will resume operation on April 1, after receiving a series of upgrades to its lasers, mirrors, and other components at the twin detectors located in Washington and Louisiana.

Joining the search will be Virgo, the European-based gravitational-wave detector, located at the European Gravitational Observatory (EGO) in Italy, which has almost doubled its sensitivity since its last run and is also starting up April 1.

LIGO first made history in 2015 by making the first direct detection of gravitational waves via its Advanced LIGO project. The ripples travelled to Earth from a pair of colliding black holes located 1.3 billion light-years away.

Since then, the LIGO-Virgo detector network has uncovered nine additional black hole mergers and one explosive smashup of two neutron stars. That event, dubbed GW170817, generated not just gravitational waves but light, which was observed by dozens of telescopes in space and on the ground.

The University of Birmingham has been involved in the Advanced LIGO project since its inception. Members of the Institute for Gravitational Wave Astronomy have developed and built components for the LIGO instruments, such as the high-performance sensors and control electronics for the suspension systems. Birmingham physicists have contributed to the commissioning of the instruments leading to the performance that has enabled these remarkable observations to date.

Birmingham's scientists have also developed the techniques essential to tease out the signatures of gravitational waves from the data and extensively contributed to the analysis of the data collected during the science runs that have led to the observation of these 11 binary systems. Birmingham’s researchers have pioneered the framework and analysis algorithms that are at the heart of the study of the physics of compact binary systems, their astrophysical evolution and tests of Einstein's theory with gravitational-wave observatories.

Professor Alberto Vecchio, Director of the Institute of Gravitational Wave Astronomy, University of Birmingham said: "The LIGO and Virgo instruments at this improved sensitivity will survey a volume of the universe about three times as large as the one that has been covered so far. We are going to observe many new cosmic collisions of black holes which will surely give us new information about the properties of these mysterious objects. But what I am really looking forward to is to be surprised: maybe we’ll detect some completely unexpected sources."

Professor Andreas Freise, Deputy Director, Institute of Gravitational Wave Astronomy said: "The LIGO detectors are being improved step by step, following a carefully laid out plan. Most recently the addition of squeezed light and an increase in laser power have given a big push to the sensitivity of the detectors.

"It is now time again to switch LIGO and Virgo into observing mode. We pause improving the detectors for about one year and listen to gravitational wave signals from the universe instead. We expect to find many more black hole signals and have good chances of observing new and yet undiscovered types of cosmic events."

In this next run, LIGO will be able to see those events out to an average of 550 million light-years away, or more than 190 million light-years farther out than before.

For further information please contact Beck Lockwood, Press Office, University of Birmingham, tel 0121 414 2772.

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