Linked radio telescopes provide SKA teaser

SKA dishes by night. Credit: SPDO/TDP/DRAO/Swinburne Astronomy Productions

SYDNEY: Six Australian and New Zealand telescopes have been linked together to give us an early glimpse of the possible discoveries the world can make with the international Square Kilometre Array (SKA) radio telescope.

The six telescope link-up has been announced at the fourth annual International SKA Forum taking place this week in Banff, Canada. The telescopes are working together as one, taking pictures of space that offer a taste of the unprecedented capacity of the long baseline array planned for the SKA.

“Astronomers made the historic link on 29 June to observe a radio source that may be two black holes orbiting each other. The data from all six sites was streamed in real time to Curtin University in Perth and processed to make an image,” Australian Innovation Minister Senator Kim Carr said.

Distant galaxies in detail

This ability to successfully link antennas (dishes) over large distances will be vital for the future $2 billion SKA telescope, which will have several thousand antennas, up to 5,500 km apart, working together as a single telescope.

Linking antennas in such a manner allows astronomers to see distant galaxies in more detail. The radio source the astronomers targeted was PKS 0637-752, a quasar that lies more than seven and a half billion light-years away from us.

This quasar emits a spectacular radio jet with regularly spaced bright spots in it, like a string of pearls. Some astronomers have suggested that this striking pattern is created by two black holes in orbit around each other, one black hole periodically triggering the other to ‘feed’ and emit a burst of radiation.

“It’s a fascinating object, and we were able to zoom right into its core, seeing details just a few millionths of a degree in scale, equivalent to looking at a 10-cent piece from a distance of 1000 km,” said CSIRO astronomer Tasso Tzioumis.

“If you had to identify one of the current ‘big science questions’, I think it’s the origin and nature of dark energy,” said Brian Boyle, anzSKA project director, dubbing it a “known unknown”. “But what’s more exciting is the ‘unknown unknowns’ that would revolutionise our understanding of the universe and transform our thinking into to something completely different.”

Contenders for final site

Currently Australia and South Africa are vying to be chosen by the SKA Board of Directors as the main site for what will be the world’s largest and most sensitive radio telescope – 10,000 times more capable than any existing telescope. The two countries have been shortlisted because they can offer the best conditions in which to conduct radio astronomy, with radio quietness being one of the main considerations.

“We have excellent radio quietness, we have the flexibility to host array stations away from radio interference, we have very good protection for radio quietness, plus we have 800 people involved in professional astronomy in Australia,” said Carr of the Australian site’s merits.

“We have an enormously strong record in astronomy and are world leaders in many branches of astronomy. We are able to support the discoveries of this project as a result of out universities, scientific agencies and people,” he added.

Amazing IT challenges

The Australian and New Zealand committee are currently responding to a request for information, about radio quietness, cost and geophysical requirements by the SKA head office (SPDO), and will submit their final report on September 15.

The submitted information will be analysed by independent consultants, expert panels and the SPDO before being handed to the SKA Site Advisory Committee (SSAC), an external body of independent experts, in November. By February 2012 the SKA Board of Directors will receive the final report and recommendation before making the site decision.

“There are some amazing challenges,” said Peter Quinn, director of the International Centre for Radio Astronomy Research in Western Australia.

“This is mainly a software and IT telescope. It will generate the same amount of data in a day as the entire world does in a year, which is beyond the scope of what the whole planet can currently provide. The big picture of what this machine can do is driving interest around the world.”