A team of young local artisans from the town of Carnarvon in the Karoo, Northern Cape, is involved in the building of the Phase 1 of the HERA telescope. The Karoo region is home to the Square Kilometre Array (SKA), the world biggest intergovernmental radio telescope project being built in Australia and South Africa.
According to the South African Radio Astronomy Observatory (SARAO), there were four artisans during the first construction in the early 2015 and the number has since grown to 20 people with matric as the entry level qualification but a lot of them have excellent experience.
SKA project is one of the strategic sectors that government, through the department of science and innovation, has earmarked to drive job creation by providing practical technical skills to graduates and the youth in general.
The HERA telescope is an array of 350 antennas situated next to MeerKAT – a predecessor to the SKA telescope. Led by the US team, the project is considered one of the largest collaborations with a strong South African participation, from construction to science. The main goal of HERA is to observe how the first structures formed in the very early stages of the Universe, as the first stars and galaxies lit up space.
HERA comprises 14-meter diameter dishes, packed closely together and pointing straight up at the sky, explained SARAO. The telescope detects radio frequencies from outer space similar to the ones used in our FM car radios. It is built using wooden poles, a PVC-pipe structure and wire mesh, but this seemingly simple structure is masking a state-of-the-art technology that provides an aperture for astronomers to peer into the universe deeper than ever before.
A glimpse of the Universe
SARAO, as the hosting organisation and contributing partner in the broader HERA project, is charged to provide the necessary construction management, systems engineering, and location, power and fibre networks needed to operate the HERA instrument. The HERA has now released its first set of observations to the world, giving a glimpse of what the Universe looked like about 13 billion years ago, according to SARAO’s website. Cape Town-based Kathryn Rosie, who was a HERA Project engineer at the time and Matthys Maree, who was filling in as construction supervisor, led the Karoo team.
Said Rosie: “Construction of the array is phased in such a way that, as antennas are completed, they are hooked into the telescope data correlation system. This enables observations and early science to be carried out while construction continues.” Rosie added that after the initial construction, Phase I observations were carried out in 2017-2018 throughout the Southern Summer using about 50 dishes. Astronomers are keen to understand how the Universe reached conditions for the very first stars and galaxies to form and HERA will help them unravel how this happened.
“Even the most powerful optical and infra-red space telescopes like the Hubble Space Telescope or its upcoming successor, the James Webb Space Telescope won’t be able to look that far back in time. That is one of the reasons why radio astronomy is so important,” observed Professor Mario Santos, currently representing SARAO on the HERA board.
The release of the Phase I data, was accompanied by a few but insightful scientific journal articles co-authored by scientists from the universities of the Western Cape, Rhodes, and KwaZulu-Natal along with the international team. One of the papers presents the most sensitive upper limits to date on the strength of the signal we can detect from the Universe at around 66 million years after the Big Bang. One of the lead scientist behind this paper, Dr Nicholas Kern, noted that “this analysis is a big step in demonstrating HERA’s unprecedented sensitivity going forward as construction is completed: with only a couple of weeks of data from the array at fractional capacity we are already producing world-leading limits”.
A second paper elaborates further on the implications of those upper limits for models of early universe star and galaxy formation. Currently the array stands at a total of 332 dishes with the remainder projected to be completed in the coming weeks. The current project engineer, Dr Nicholas Kern, said all is going well with regards to commissioning and construction. He said they are currently “conducting a logistic and support analysis to ensure smooth operations for the coming seasons in order to facilitate future discoveries.”
Unveiling the mysteries
Said Dr David De Boer, HERA project manager, from the University of California, Berkeley: “The upcoming observations with the enhanced HERA array should allow us to observe the lighting up of the very first stars after the Big Bang.” It is hoped that this data release begins a new adventure of unveiling the mysteries of the early Universe, thanks to the skilled hands of Carnarvon artisans.