Discovering the Universe's First Stars: Scientists on the Brink with HERA Radio Telescope Upgrade

 The Hydrogen Epoch of Reionization Array (HERA) radio telescope system is undergoing a significant upgrade that could soon unveil the universe's first stars, which emerged following the enigmatic Dark Ages. This event, known as the "cosmic dawn," marked the beginning of star, galaxy, and quasar formation, and led to the reionization of the universe – the process that ionized hydrogen gas, which was the most abundant element at the time.

Cosmic dawn is believed to have started gradually between 250 to 500 million years after the Big Bang, with the process concluding around 1 billion years later. It was then that the cosmos began to resemble its current form. While some cosmic models provide insight into this significant event and the universe's early characteristics, they remain unproven. Consequently, researchers and engineers are continuously developing increasingly sensitive instruments to detect any evidence of the universe's infancy.

Among these tools is HERA, a collection of 350 radio telescopes situated in South Africa's Karoo desert. While it has yet to detect the initial signs of cosmic dawn, a team of scientists from North America, Europe, and South Africa has successfully doubled HERA's sensitivity. As Adrian Liu, professor at McGill University, stated, "While this detection remains elusive, the HERA results represent the most precise search to date." With the upgrade complete, astronomers are now poised to gather new data.

Once HERA's antennas are fully calibrated and operational, the team plans to create a 3D map of ionized and neutral hydrogen "bubbles" situated over 13 billion light-years away. The presence of these bubbles should indicate the location of the first galaxies. If successful, this map could illuminate the differences between the universe's first stars and galaxies and those we observe today. The research detailing the HERA upgrade has been published in The Astrophysical Journal.