Onwards and upwards for SKA Featured

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The SKA radio telescope being built in the Karoo will end up being the world’s largest when it is completed, listening to space signals with a sensitivity that’s 100 times greater than any current radio telescope on earth. Designed to try and ‘see’ the first stars and galaxies being formed during the period that scientists call the Epoch of Reonization (EoR), this international project has already started ‘finding’ previously unknown celestial events.

HERA telescopeThe Hydrogen Epoch of Reionization Array (HERA), which commenced construction near the MeerKAT radio telescope in 2015, is one of the two telescopes making up the SKA. To date 35 14-metre diameter dishes have been erected, with hundreds more planned.

Last year, the National Science Foundation (NSF) invested $9.5 million (equivalent to approximately R124 million) in the project. This money has been allocated to allow the array to expand to 240 radio dishes by 2018. This week, the Gordon and Betty Moore Foundation provided another big financial boost of USD$5.8 million (R75 million).

The cash injection will help allow the radio telescope to expand to 350 dishes. According to reports, the new grant will permit the sensitivity of the array to be increased and potentially detect signals coming from a time before the EoR, believed to be roughly 400 million years after the Big Bang. The array will be able to access a cosmological signal roughly 100 000 times fainter than emissions from the Milky Way and nearby galaxies.

“Observations at the lowest radio frequencies (<100 MHz), allow for observations of the epoch that precedes cosmic reionization where X-rays are expected to have heated the intergalactic medium. As X-rays are expected to be generated by accretion on black holes, observations of this epoch will directly probe the properties of the first black holes formed in the Universe,” Dr Gianni Bernardi, SKA South Africa senior astronomer, explained in a statement.

HERA is made up of a close-packed array of fixed parabolic dishes. The centre position of each dish is determined by the placement of a concrete hub. These hubs constrain radial PVC spars, tensioned into approximate parabolas against a rim, which is supported by telephone poles. Welded mesh panels are installed on these spars to form the reflector surface.

It is hoped that by probing the 3-D structure of the universe during the very first appearance of stars, galaxies and black holes, different scenarios for the first generation of stars could be distinguished. While that might not sound ground-breaking, it could fundamentally change our knowledge of how the universe functions.

Image credithttp://www.ska.ac.za/gallery/hera/

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