Scientists at the Hartebeesthoek Radio Astronomy Observatory (HartRAO) and the Karoo Array Telescope (KAT-7) have collaborated to conduct the first very long baseline interferometry (VLBI) observation in South Africa without the assistance of other countries.
Square Kilometer Array (SKA) South Africa Director Dr Bernie Fanaroff has hailed the “detection of fringes” in the experiment as “an important milestone”. The experiment linked a 26m HartRAO dish near Pretoria teamed with one of the seven 12m KAT-7 dishes at Klerefontein near Carnarvon in the Northern Cape. The dishes, some 900km apart, were linked to jointly observe and record data from a distant radio source known as 3C273. The data was then correlated in Cape Town to produce the first ever African fringe detection at its first attempt, the Department of Science and Techology said in a statement.
“VLBI is significant as it’s used for imaging distant cosmic radio sources, spacecraft tracking, and for applications in astrometry. However, it can also be used ‘in reverse’ to perform earth rotation studies, map movements of tectonic plates very precisely (within millimetres), and other types of geodesy,” says Fanaroff.
In addition to the fringe detection breakthrough, South African engineers have also built the building block for the next generation of digital processing systems, vital for the SKA. The reconfigurable open architecture computing hardware (ROACH) board is primarily a South African development and already in use in 300 high-tech facilities around the globe. However, ROACH-2 prototypes are much faster and more powerful.
“To put it in perspective SKA is expected to collect more data in one week than humankind has collected in its entire history,” says Fanaroff of the 3000 to 5000-dish telescope that will be built by an international scientific consortium either in South Africa or in Australia. Fanaroff says the leap forward in technology is largely thanks to advances in field-programmable gate array (FPGA) technology. He notes the “good news” is that progress in FPGA is set to hold for another four generations, so future iterations of ROACH (3, 4, 5 and 6) are likely in the next few years. “This is all essential preparation for the SKA project,” explains Fanaroff. “SKA will revolutionise science. It will be the world’s largest radio telescope and probably capable of answering questions that we haven’t even thought to ask yet,” elucidates Fanaroff.
Expected scientific discoveries range from understanding the cosmic web of neutral gas, which will unravel how the first stars and black holes were formed. It will track galaxies to investigate the rate of expansion of the universe and hopefully identify the nature of dark energy. It will also produce three-dimensional galactic maps and detect what are lightly to be extremely weak extra-terrestrial signals and pinpoint planets capable of supporting life. It will also allow for the study of gravity, which could possibly lead to the theory of relativity being challenged. Pulsars, the collapsed spinning cores of dead stars, will also be monitored providing information on gravitational waves and black holes.
“In 2011 South Africa in conjunction with its eight African-partner countries bidding communally for the SKA will pull out all the stops to show the world that Africa is the future as far as science and technology are concerned,” says Fanaroff.
Cabinet in 2009 approved a R1.6 billion budget to win the right to host the instrument. This includes the construction of two demonstration instruments, KAT-7 and a larger MeerKAT of some 65 dishes. Construction of the KAT-7 began in July 2009 and was completed in January 2010. MeerKAT is scheduled for completion by December next year and should commission in 2013 at a cost of R860 million.
An international panel will next year decide where to build the SKA with construction slated to start in 2013. South Africa was shortlisted for the facility – along with Australia – in 2006. The SKA is set to cost €1.5 billion (R14.6 billion today) and will earn its host about €200 million (R1.954 billion) a year for 20 to 30 years in expenses related to operations and maintenance, Minister of Science and Technology Naledi Pandor said last November.