Funding to improve global gravitational wave network

A global network of gravitational wave observatories will be upgraded to almost double its sensitivity, the lead science funding agencies of the United Kingdom and United States announced today. 

The $US30 million Advanced LIGO Plus (ALIGO+) project will improve the two existing Laser Interferometer Gravitational wave Observatories (LIGO) in the United States, and will be included as standard in the new LIGO India facility from the mid-2020s. 

The US National Science Foundation is providing $20.4 million funding for ALIGO+, and UK Research and Innovation (UKRI) £10.7 million ($US14.1 million), with additional support from the Australian Research Council. 

The University of Birmingham has been involved in the Advanced LIGO project since its inception. Members of the Institute of 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.

Professor Alberto Vecchio, of the Institute for Gravitational Wave Astronomy at the University of Birmingham says: “LIGO A+ is the next leap in sensitivity to probe even deeper into the Universe. There is great excitement for all of us in Birmingham to be part of this project with our UK and US colleagues and to continue to drive this field to new horizons.”

Dr Conor Mow-Lowry, also of the Institute for Gravitational Wave Astronomy, adds: “Gravitational Waves have exploded into the world of astronomy – eleven times so far! The A+ upgrade lets us build on this success by making crucial upgrades that will give us the most bang for the buck.”

NSF Director France Córdova said: “This award ensures that LIGO, which made the first historic detection of gravitational waves in 2015, will continue to lead in gravitational wave science for the next decade. 

“With improvements to the detectors -- which include techniques from quantum mechanics that refine laser light and new mirror coating technology -- the twin LIGO observatories will significantly increase the number and strength of their detections. Advanced LIGO Plus will reveal gravity at its strongest and matter at its densest in some of the most extreme environments in the cosmos.  

“These detections may reveal secrets from inside supernovae and teach us about extreme physics from the first seconds after the universe's birth.” 

UK Research and Innovation Chief Executive, Professor Sir Mark Walport, said: “In confirming the existence of gravitational waves, the LIGO project generated unique insights into the nature of our universe and fuelled world-wide interest in science. This Nobel-winning project also illustrated the importance of international collaboration in research.

“The UK’s technological and scientific expertise will continue to play a crucial role in ALIGO+, which aims to further increase our understanding of the events that shape the universe. The UK investment in ALIGO+ and support for a third gravitational wave detector in India underlines UKRI’s commitment to developing existing collaborative research and innovation programmes with partners.” 

The enhanced capabilities afforded by ALIGO+ are expected to illuminate the origins and evolution of stellar-mass black holes, allow precision tests of extreme gravity, enable detailed study of the equation of state of neutron stars, and permit new tests of cosmology, including fully independent constraints on the Hubble constant.

Technology improvements arising from the project are expected to include quantum optics, quantum information theory, materials science, optical technology, precision metrology and physical standards. 

UKRI funding is provided through its Science and Technology Facilities Council (STFC), from the Fund for International Collaboration. 

Gravitational waves are ripples in space caused by massive cosmic events such as the collision of black holes or the explosion of supernovae. They are not electromagnetic radiation, and as a result were undetectable until the technological breakthroughs at LIGO enabled in part by UK technology. 

At each LIGO site, twin laser beams are transmitted down two 4-kilometre long tubes kept under a near-perfect vacuum, and arranged as an L-shape. The beams are reflected back down the tubes by mirrors precisely positioned at the ends of each arm.  As a gravitational wave passes through the observatory, it causes extremely tiny distortions in the distance travelled by each laser beam.

As a result of the UK-built systems which hold the mirrors in place, a distortion of just one-ten-thousandth the diameter of a proton can now be measured – not only enabling the detection of gravitational waves for the first time, but also making LIGO the most sensitive measuring instrument ever.   

In the UK, the ALIGO+ project will involve the Universities of Glasgow, Birmingham, Cardiff, Strathclyde and STFC’s Rutherford Appleton Laboratory. 

The UK is also supporting the construction of a third LIGO detector, in India. LIGO-India is expected to become operational at about the same the time as ALIGO+ in 2025, with the design changes included from the start. This will form a global network of five detectors – the others being in Italy and Japan.