CAPTION: HERA telescope under constsruction at the SKA site in the Northern Cape. The project received a R75 million cash injection from a US organization.
The awarding of a R75 million grant by a United States-based organisation towards the construction of the Hydrogen Epoch of Reionization Array (HERA) radio telescope in the Karoo is evidence of the region's growing attractiveness as a hub for global astronomy research, says the Department of Science and Technology (DST).
HERA is expected to assist astronomers view the Universe's first stars and galaxies. The construction of HERA started in 2015 and already 35 of the 14-metre diameter dishes have been erected.
TheGordon and Betty Moore Foundation grant will assist with the further expansion of the radio telescope to 350 dishes.
With the new grant, the sensitivity of the array can be increased and has the potential to detect signals coming from a time before a period the scientists call the Epoch of Reionization in the history of the Universe, the Cosmic Dawn, roughly 400 million years after the Big Bang. HERA will be able to access a cosmological signal roughly 100 000 times fainter than emissions from the Milky Way and nearby galaxies.
The DST's Acting Chief Director for the Square Kilometre Array (SKA) and African Very Long Baseline Interferometry, Takalani Nemaungani, said the cash injection was a recognition of the attractiveness of the Karoo as an excellent location for astronomy in the country, especially that several universities, science teams and engineering students were actively involved in building the radio telescope.
"Government's investments in astronomy in South Africa are also paying off," said Mr Nemaungani, adding the latest grant for the HERA was another form of foreign direct investment in the country, through science, technology and innovation.
Last year, the National Science Foundation (NSF) invested approximately R124 million in the project, and HERA was granted the status of an SKA precursor telescope. The NSF funding allowed the array to expand to 240 radio dishes by 2018.
HERA is one of a number of low frequency radio telescopes that will be instrumental in detecting the distinctive signature that will allow astronomers to understand the formation and evolution of the very first luminous sources – the first stars and galaxies in the Universe – the Epoch of Reionization.
Dr Gianni Bernardi, SKA South Africa senior astronomer working on HERA, says: "This increase in collecting area provides the sufficient sensitivity to attempt imaging large ionized bubbles rather than measuring 'only' their statistical properties."
Using this next-generation instrumentation for 21-cm cosmology – the wavelength of neutral hydrogen gas radio waves – HERA will probe the 3D structure of the Universe during the very first appearance of stars, galaxies and black holes. This first generation of hot massive stars and black-hole binaries filled the intergalactic medium with X-rays.
"Observations at the lowest radio frequencies (under 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," says Bernardi.
HERA comprises a close-packed array of fixed parabolic reflector elements (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 utility (telephone) poles. Welded mesh panels are installed on these spars to form the reflector surface.
Project Engineer Kathryn Rosie, who is responsible for HERA's construction in the Karoo, said five local residents, who have been part of the HERA construction crew since 2015, have recently taken up positions as HERA team leaders in anticipation of the crew expansion for the "big build" in early 2017.
"In addition to maintaining construction activities, they now have the added responsibility of training new construction team members. The build-out plan for the next construction phase sees five teams working in parallel to achieve the build targets, which require an output of approximately 100 dishes per year, and it is expected that the entire crew contingent will be made up of Karoo residents."
So far, more than R1,7 million has been spent … to purchase the material with which the telescope is being built. We are proud of the fact that all of the build materials, items, and labour involved in the construction of the reflector elements have been sourced from within South Africa, with most of our bulk materials being sourced from within the Karoo region," she said.
Dr Rob Adam, Managing Director of SKA South Africa, said the additional funding was evidence of the confidence the international community had in the excellent skills and results South Africa was demonstrating. Furthermore, SKA SA remained committed to ensuring that local communities and businesses benefit from the construction of radio telescopes in the Karoo, and HERA is a fine example of that."
SKA SA Head: Communication and Stakeholder Relations
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