Sunday, February 17, 2019

US-UK-Australia Funding to Improve Global Gravitational Wave Network

Artist's illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling space-time grid indicates the isotropic gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies.  Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet

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 have announced. 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.

NSF Director France C√≥rdova 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 fueled 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 programs 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.

Dr David Reitze is Executive Director of the LIGO Laboratory. “The UK has always played a critical and innovative role in gravitational wave detector development, most recently providing the test mass suspensions, a key component to the Advanced LIGO interferometers. ALIGO+, the next phase of Advanced LIGO, continues in that tradition. The UK-Australia-US partnership will bring Advanced LIGO to a level where we will detect binary black hole collisions on an almost daily basis by the middle of the next decade."

Professor Sheila Rowan is Director of the Institute for Gravitational Research at the University of Glasgow, and chair of the international scientific oversight group for gravitational wave research. She said: “If a normal telescope ‘sees” the Universe, LIGO is akin to ‘hearing’ the Universe. The improved sensitivity from ALIGO+ will allow us to better understand what the Universe is telling us, information that we’ve been unable to hear until now.”

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-kilometer 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 traveled 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.


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