Baby MeerKAT exceeds expectations

The first image from South Africa’s MeerKAT telescope shows that the telescope “will be a remarkable discovery machine”, MeerKAT chief scientist Dr Fernando Camilo said on Saturday.

“The images tell us all that MeerKAT is the best telescope of its kind in the southern hemisphere, with only 16 dishes,” he told an assembled audience of ministers, deputy ministers and visitors to the Square Kilometre Array (SKA) site in the Northern Cape.

On Saturday, Science and Technology Minister Naledi Pandor inaugurated the first 16 dishes of the MeerKAT telescope – and unveiled its first image. By the end of next year, the MeerKAT telescope, which is South African designed and built, will comprise 64 dishes.

These giant two-storey dishes rise up out of the centre of the MeerKAT core area, standing incongruously against a backdrop of ocre sand and scrubland. Others wait to be assembled, their white metal bowls ready to be hoisted onto waiting pedestals.

“When the full 64-dish MeerKAT is available, it will be the best telescope of its kind in the world,” said Camilo, formerly of Columbia Univeristy who took up the post in April.

“It is very, very difficult to get to this stage [as there is usually a process of trouble-shooting before a telescope can produce a high-quality image]. It tells us and the world that we have a working telescope in the Karoo,” he said.

Although the R3-billion MeerKAT is South Africa-owned and funded, it will be incorporated into the SKA, which will be the largest telescope in the world. The SKA will be hosted by Australia and South Africa, with satellite sites in eight African partner countries. It will seek to answer some of humanity’s most enigmatic questions: are we alone in the universe, what is dark matter, how do galaxies evolve, what happened after the Big Bang?

From 2018, another 133 dishes will be added to MeerKAT to form part of the phase one of the SKA, which has been capped at EUR650-million. In Australia, about 130 dipole antennas, which look like six-foot-tall Christmas trees made out of thick wire, will be constructed as part of this phase.

South Africa decided to build MeerKAT, even before it was announced in 2012 that the SKA would be split between the two countries. Part of the idea at the time was to showcase South Africa’s scientific and engineering capabilities and prove that the country could in fact build and host a radio telescope. The other part was to ensure that it would have a legacy project in case the country lost the hosting bid.

“This is not just an unveiling,” Pandor said at the MeerKAT-16 inauguration. “We want to show the world the kind of research that the MeerKAT-16 makes possible…. We were only meant to reach this [quality of image] at 32 [dishes], not 16.”

It is difficult and expensive to engineer a radio telescope with only one big dish. This is why the MeerKAT – and ultimately the SKA – is an interferometer, which uses many smaller dishes to act as one giant telescope. What this means practically is that an interferometer can be brought online in phases, and the radio telescope can undertake science even though all of its phases are not operational.

Prof Justin Jonas, SKA South Africa chief technologist, said he was “amazed” at the quality of the image, although “there are no accidents here. It’s been a coherent effort from the whole team and the National Research Foundation and the Department of Science and Technology…. We hired the right people, had the right processes in place.”

“Personally, I’m very, very excited,” Jonas, who attended the first international SKA meeting as South Africa’s ambassador, said. “I’ve been wanting to build a radio telescope since I was a kid, and now we have. How many people get to do that? And it’s working!”

The released image is a picture of about 1300 radio galaxies, of which only 70 had been imaged before, Jonas said.

Celestial objects, like stars and galaxies, emit radio waves, which cannot be seen with the naked eye. Radio telescopes receive these relatively weak signals from the universe and turn them into maps and images of the universe. The radio spectrum is substantially broader than that of visible light, which means that scientists can “see” more with radio telescopes.

The “first light” image was taken in the L-band, which is a portion of the radio spectrum. This band is of interest globally because it contains information about how the universe and how galaxies evolve, among other things. MeerKAT is expected to be twice as sensitive in this band as was originally anticipated. This means that an experiment in this band could take a quarter of the time it was originally allocated.

However, Pandor said that there was more to South Africa’s astronomy investment than pure science: “Big science brings opportunity to South Africa and the African continent. The SKA brings opportunities to this area, opportunities they hadn’t hoped for.”

It was “not always easy to convince governments to support long-term projects and initiatives, especially in science … [where] there are often nuanced impacts that are not immediately visible”, she said, encouraging dignitaries including Economic Development Minister Ebrahim Patel and 11 deputy ministers from a number of departments, to become “ambassadors for science and the SKA”.

“Science and astronomy science can change lives, change communities, build human capital…. Through science, in South Africa and Africa, we are able to advance development.”

Wild was a guest of the Department of Science and Technology and SKA South Africa

  • This article was first published by Independent Newspapers.

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