A team of researchers from North America, Europe, and South Africa doubled the sensitivity of the Hydrogen Epoch of Reionization Array (HERA) radio telescope.
A team of researchers from North America, Europe, and South Africa doubled the sensitivity of the Hydrogen Epoch of Reionization Array (HERA) radio telescope. They hope to discover the secrets of the early universe with this breakthrough.
Astronomers have made significant progress towards unravelling the mysteries of the cosmic dawn. A network of 350 radio telescopes in South Africa’s Karoo desert is making rapid progress towards detecting the “cosmic dawn” – the period after the Big Bang when stars first lit up and galaxies began to flourish.
“Teams from all over the world have been working for decades to make the first detection of radio waves from the cosmic dawn.”
While such a detection remains elusive, HERA radio telescope findings represent the most precise pursuit to date,” says Adrian Liu, an Assistant Professor at McGill University’s Department of Physics and the Trottier Space Institute.
The array was already the most sensitive radio telescope in the world dedicated to exploring the cosmic dawn. Now the HERA team has improved its sensitivity by a factor of 2.1 for radio waves emitted about 650 million years after the Big Bang and 2.6 for radio waves emitted about 450 million years after the Big Bang. Their work is described in a paper published in The Astrophysical Journal.
Although the scientists have yet to detect radio emissions from the end of the cosmic dark ages, their findings provide information about the early universe’s star and galaxy composition.
So far, their data indicate that, unlike our galaxies today, early galaxies contained very few elements other than hydrogen and helium. Today’s stars contain a variety of heavier-than-helium elements ranging from lithium to uranium.
When the radio dishes are fully operational and calibrated, the team hopes to create a 3D map of the bubbles of ionised and neutral hydrogen – markers for early galaxies – as they evolved from about 200 million years after the Big Bang to around 1 billion years later.
According to the researchers, the map could reveal how early stars and galaxies differed from those we see today, as well as how the universe appeared in its infancy.
The fact that the HERA team has yet to detect these signals, according to the researchers, rules out some theories about how stars evolved in the early universe. “Our findings suggest that early galaxies were about 100 times brighter in X-rays than galaxies today.”
“There was lore that this would be the case, but now we have actual data that supports this hypothesis,” Liu says.
The HERA team is still working on improving the telescope’s calibration and data analysis in the hopes of seeing those bubbles in the early universe.
Filtering out the local radio noise to see the signals from the early universe, on the other hand, has not been easy. “If it’s Swiss cheese, the holes are made by galaxies, and we’re looking for the cheese,” says David DeBoer, a radio astronomer at the University of California, Berkeley.
“HERA is improving and setting better and better limits,” says Aaron Parsons, HERA’s principal investigator and Associate Professor of Astronomy at the University of California, Berkeley. “It’s fantastic that we’re able to keep pushing forward, and that we have new techniques that are bearing fruit for our telescope.”