By K.S. Jayaraman
Time is running out for an Indo-Australian plan to join the US Laser Inferometer Gravitational-Wave Observatory (LIGO) network. The detector, to be installed at Gingin in Western Australia, is scheduled to begin collecting data in 2017 -- but only if the two countries can commit the required funding by October 2011.
Predicted by Albert Einstein in 1916 as part of his theory of general relativity, gravitational waves are ripples in the fabric of space and time caused by objects moving with accelerated, non-symmetrical motion. If found, the waves promise to open a new branch of astronomy, but they have so far escaped direct detection.
The existing LIGO detectors -- two in Hanford, Washington, and the other in Livingston, Louisiana -- have been searching for the waves without success since 2002, in partnership with the GEO600 detector in Hanover, Germany, and the Virgo detector in Cascina, Italy. Hope is now pinned on 'Advanced LIGO' and 'Advanced Virgo' projects to upgrade the existing detectors and make them ten times more sensitive.
Stanley Whitcomb, a physicist at the California Institute of Technology in Pasadena and chief scientist of LIGO, says that locating one of the advanced LIGO detectors in Australia, far from the existing observatories, will improve physicists' ability to pinpoint gravitational waves. "Detectors in the United States and Europe are a good start, but there is a pressing need for one in the Southern Hemisphere," he says. "LIGO Australia is our attempt to fill this need, and I envision this as providing a focus for gravitational-wave research in the Asia-Pacific region for the next decade or two."
Whitcomb says that the US National Science Foundation (NSF), which owns the instruments, has approved the transfer of the detector parts to Gingin. The Australian detector would be operated by the Australian Consortium for Interferometric Gravitational Astronomy (ACIGA), a group of five universities in the country. But there is a catch: ACIGA must find around AU$140 million ($139 million) to build a facility to house the detector, plus another AU$60 million to meet running costs, and the NSF needs to know soon whether that will happen.
"We have to know if Australia can commit to the project or not by October 2011," says Whitcomb. Otherwise, according to LIGO's commitment to the NSF on the schedule of installation, "we will have to start installing the detector in its originally planned location, at our LIGO Hanford site".
The deadline pressure and the amount of money needed have forced ACIGA to look for international partners. The Indian Initiative in Gravitational-wave Observations (IndIGO) -- a group of seven national institutions -- answered the call, offering to seek AU$30 million from the its government to pay 15% of the costs over the period 2011-22.
The project "presents Indian science with an historic opportunity", says Bala Iyer, a theoretical physicist at the Raman Research Institute (RRI) in Bangalore and chairman of IndIGO.
Iyer and his group at the RRI have worked in theoretical gravitational-wave research for more than 20 years, collaborating with Sanjeev Dhurandhar, a data analyst and modeller at the Inter University Centre for Astronomy and Astrophysics in Pune. Iyer says that LIGO promises to extend this alliance to experimental work, with participation from other members of the consortium, including C. S. Unnikrishnan, a high energy physicist at the Tata Institute of Fundamental Research (TIFR) in Mumbai, and colleagues at the Raja Ramanna Centre for Advanced Technology in Indore. IndIGO also sees the partnership as a short cut to its goal of building an Indian gravitational-wave detector by 2020.
The project has high-profile support in India: Mambillikalathil Menon, a cosmic-ray physicist and former science minister, is backing the bid. "I have strongly supported IndIGO's request in my letter to the chairman of the Department of Atomic Energy," he told Nature. "Personally, I think the collaboration gives us a chance to enter gravity-wave astronomy at just the right time, when the field is about to open up. We cannot afford to miss it."
Iyer points out that India has a significant budget for "large serious projects in fundamental science", and AU$30 million is a small amount compared with what the country has committed to other projects in physics.
But much depends on whether ACIGA can secure its share. The proposal was submitted to the Australian government last week, but with the short timescale for decision making, and the floods and cyclone that devastated parts of the country earlier this year stretching budgets, the probability of success is "very difficult to assess", says Jesper Munch, an experimental physicist at the University of Adelaide and chairman of ACIGA. "But we are optimistic that such a unique opportunity for Australia will be considered positively, and the possible contribution by India via the IndIGO-ACIGA partnership could very significantly improve our chances."