The HERA telescope, an array of 350 antennas situated next to MeerKAT in the Northern Cape province of South Africa, is being built by a team of local artisans from the town of Carnarvon.
It 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.
A team of four Carnarvon based artisans began construction of the HERA telescope in early 2015. The team was supervised by Cape Town-based Kathryn Rosie – HERA Project Engineer at the time, and Matthys Maree (Carnarvon) – at the time filling in as construction supervisor. “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,” says Rosie. After the initial construction, Phase I observations were carried out in 2017-2018 throughout the Southern Summer using about 50 dishes.
HERA is an array of 14-meter diameter dishes, packed closely together and pointing straight up at the sky. 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 deceivingly simple set-up hides a state-of-the-art technology that makes it possible for astronomers to peer into the universe deeper than ever before.
A US-led project, HERA is a large international collaboration, with a strong South African participation, from construction to science. The 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.
The South African Radio Astronomy Observatory (SARAO), the hosting organisation and contributing partner in the broader HERA collaboration, is responsible for providing the necessary construction management, systems engineering, location, power and fibre networks needed to operate the HERA instrument. The original building team in Phase I grew from four artisans to over 20 people with at most a matric qualification but a lot of excellent experience, all from the local town of Carnarvon. Currently for Phase II, the building team comprises 10 artisans.
Astronomers are eager to understand how the universe reached conditions for the very first stars and galaxies to form and HERA will help them understand how it 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,” says Prof. Mario Santos, currently representing SARAO on the HERA board.
Accompanying the Phase I data release, a few scientific journal articles were co-authored by scientists from the University of the Western Cape, Rhodes University, and the University of 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. The lead scientist behind this paper, Dr Nicholas Kern, currently a postdoctoral fellow at MIT, says “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 further elaborates on the implications of those upper limits for models of early universe star and galaxy formation.
Nearly six years after construction began, the array stands at a total of 332 dishes with the remainder planned to be completed in the coming weeks. “Commissioning and construction activities are progressing well, we are currently conducting a logistic and support analysis to ensure smooth operations for the coming seasons in order to facilitate future discoveries,” adds current project engineer Ziyaad Halday. “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,” says Dr David DeBoer, HERA Project Manager, from the University of California, Berkeley.
With this data release begins a new adventure of unveiling the mysteries of the early universe, thanks to the skilled hands of Carnarvon artisans.