Unexpected hydrogen signals from early universe galaxy
The James Webb Space Telescope has detected unexpected hydrogen radiation originating from a galaxy present in the early universe. This discovery is significant for understanding the early universe.
As specialists from the European Space Agency remind us, one of the key scientific goals of the James Webb Space Telescope is to study the beginnings of the universe more precisely than ever before. This pertains to the time when the first galaxies were forming.
The crucial factor here is the telescope's exceptionally high sensitivity to infrared light. This opens up new possibilities for investigating how these galaxies were formed and what impact they had on the universe.
The telescope has just observed the extremely distant galaxy JADES-GS-z13-1, seen at a time just 330 million years after the Big Bang. As a reminder, the universe is 13.8 billion years old.
Significantly stronger light emission
Scientists were greatly surprised by the bright emission of light at a particular wavelength, known as Lyman-α emission, which is caused by hydrogen atoms. The emission turned out to be significantly stronger than was believed possible at such an early stage of the universe's development.
"The early Universe was bathed in a thick fog of neutral hydrogen," says Roberto Maiolino of the University of Cambridge and University College London.
"Most of this haze was lifted in a process called reionisation, which was completed about one billion years after the Big Bang," he explained "GS-z13-1 is seen when the Universe was only 330 million years old, yet it shows a surprisingly clear, telltale signature of Lyman-α emission that can only be seen once the surrounding fog has fully lifted. This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surprise."
The discovery of Lyman-α radiation from this galaxy is significant for understanding the early universe, scientists emphasize.
The source of the detected radiation is not yet known. Researchers speculate that it could be ionized hydrogen surrounding the galaxy, produced by a population of unusual, very massive, hot, and bright stars. These might have been typical for this period. Another possibility could be an active center of the galaxy, powered by supermassive black holes.
Peter Jakobsen from the University of Copenhagen explained that while it was expected that Webb would surpass Hubble in detecting more distant galaxies, the true excitement lay in the unexpected insights it could offer—such as those about star formation and the appearance of black holes in the earliest periods of the universe.
