14 October 2020 22:17:12
A team of Indian astronomers has calculated the amount of hydrogen gas that contributed to star formation in the universe 10 billion years ago. He also concluded that there was enough hydrogen gas to sustain star formation for another two billion years.
Hydrogen gas in galaxies condenses to form stars. Earlier studies showed that the rate of star formation in the universe was at its peak between eight and 10 billion years ago, known as the “age of galaxy assembly,” but then plummeted. To understand why, scientists from the Pune-based TIFR-National Center for Radio Astrophysics (NCRA) and the Raman Research Institute (RRI), Bengaluru, used the modernized giant radio telescope Metrewave (uGMRT) in Junnar to study the degree of galaxy formation in 8 stars. based on available hydrogen gas.
“For the first time, we know why the rate of star formation began to decline eight billion years ago. Observations of the hydrogen signal coming from distant 8,000 galaxies have been arranged. They reveal that the availability of hydrogen gas has shrunk dramatically, slowing the rate of star formation, “said Aditya Chowdhury, a doctoral student at NCRA and lead author of the study, published in Nature on Wednesday.
With hydrogen supplies to these galaxies now depleted, Nissim Kanekar, also a co-author of the study, said: “The mass of residual hydrogen in galaxies suggests that star formation will not exceed another one or two billion years from now.”
Taking full advantage of uGMRT, which offers improved sensitivity and frequency bands, the Indian team scanned five places in the sky in 100 hours.
Unlike stars, which can be detected in optical wavelengths, atomic hydrogen signals are only captured by high-sensitivity radio telescopes when tuned to wavelengths of 21 cm.
At uGMRT, another co-author of the study, Jayaram Chengalur, said, “Previously, the field of view of the sky was much smaller and making such discoveries was not feasible.”
RRI’s KS Dwarakanath explained the limitations he faced during previous attempts to study hydrogen gas in galaxies. “The narrow bandwidth of the earlier GMRT allowed us to cover only 850 galaxies,” he said. It was uGMRT that made the study of so many galaxies possible, Chengalur said.
When galaxies are completely devoid of hydrogen, the rate of star formation will decrease and eventually stop, Chowdhury said.
📣 Indian Express is already on Telegram. Click here to join our channel (@indianexpress) and stay up to date with the latest headlines
For all the latest technology news, download the Indian Express app.
© The Indian Express (P) Ltd.