Webb telescope unveils mysterious galaxy light surprise
The James Webb Space Telescope has detected unexpected hydrogen radiation coming from a galaxy that existed in the early universe. This discovery holds significant implications for our understanding of that era.
As experts from the European Space Agency remind us, a primary scientific objective of the James Webb Space Telescope is to study the early universe more precisely than ever before, particularly focusing on the formation of the first galaxies.
The telescope's extraordinarily high sensitivity to infrared light is critically important in this realm. This sensitivity opens up new possibilities for investigating how these galaxies formed and their impact on the universe.
The telescope has recently observed an incredibly distant galaxy, JADES-GS-z13-1, seen only 330 million years after the Big Bang. For context, the universe is approximately 13.8 billion years old.
Much stronger light emission
Scientists were taken aback by a surprising phenomenon: the bright emission of light at a specific wavelength known as Lyman-alpha emission, which results from hydrogen atoms. This emission proved to be far stronger than previously thought possible at such an early stage of the universe's development.
"The early Universe was bathed in a thick fog of neutral hydrogen," explains Roberto Maiolino from 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-alpha radiation from this galaxy is crucial for understanding the early universe, scientists emphasize.
The source of the detected radiation remains unknown. Researchers speculate that it might originate from ionized hydrogen surrounding the galaxy, produced by an unusual population of very massive, hot, and bright stars. These stars may have even been typical for that era. Another possibility could be an active galactic center powered by supermassive black holes.
Peter Jakobsen from the University of Copenhagen emphasizes that although it was clear Webb would surpass Hubble in finding ever more distant galaxies, discoveries like GS-z13-1 highlight how it was also bound to unveil unexpected details about how stars and black holes began to form in the early universe.
