Webb detects Hydrogen from Ancient Galaxy (19459000)
NASA’s James Webb Space Telescope has been used by researchers to examine ancient galaxies in order to uncover the mysteries of the early cosmos. Astronomers now have detected bright hydrogen emissions from a faraway galaxy called JADES-GSZ13-1.
This galaxy was formed 330,000,000 years ago, which is an astronomically early time in history.
The brightness of the galaxy in various infrared filter was used to estimate its distance from Earth. The first redshift measured by NIRCam is 12.9.
Webb’s Near-Infrared Spectrograph was used to observe the galaxy and confirm its redshift. This spectrum confirms the 13.0 redshift.
Scientists have discovered a strange feature: a wavelength of very bright light, called Lyman alpha emission. It is produced by hydrogen. This light, which was unexpectedly bright for an early stage in the history of the universe, is much more powerful than anyone expected.
Roberto Maiolino is a member of the University of Cambridge team and University College London. The early universe was covered in a dense fog of neutral hydrogen. This haze lifted by a reionization process, completed one billion years following the Big Bang. GS-z13-1 was visible when the universe had only 330,000,000 years. It shows an incredibly clear and tell-tale sign of Lyman alpha emission, which can be only seen after the fog surrounding it has lifted. The astronomers were taken by surprise by this result, which was completely unexpected.
In the early reionization period of the universe, neutral hydrogen around galaxies, like colored glasses, blocked ultraviolet energy. This light, which includes Lyman-alpha emissions, could only escape after enough stars had formed to ionize hydrogen. The discovery of Lyman-alpha emission from this galaxy represents a major breakthrough in understanding the early phases of the universe.
The galaxy JADES GS-z13-1 is shown in this image, which was taken with NASA’s James Webb Space Telescope NIRCam’s (Near-Infrared Camera), as part of JWST’s Advanced Deep Extragalactic Survey program (JADES). Researchers were able to use the data collected by NIRCam to determine that GS-z13-1 is an extremely distant galaxy and estimate its redshift. Webb’s infrared sensitive is required to see galaxies that are so far away, as their light wavelengths have been changed into infrared during the long trip across space.
NASA, ESA and CSA Collaboration on JADES, J. Witstok, P. Jakobsen, M. Zamani, ESA/Webb, J. Witstok, P. Jakobsen, M. Zamani
Kevin Hainline is a member of the University of Arizona team. We shouldn’t be able to find a galaxy such as this given how we understand the evolution of the universe. The early universe was shrouded in a dense fog, making it difficult for even the most powerful lighthouses to peek through. Yet here is the beam of this galaxy’s light piercing that veil. The fascinating emission line can have huge implications for when and how the universe reionized.
It is still unknown what caused the Lyman alpha radiation in this galaxy, but the source could have been the first stars of the universe. The stars could have been more massive, brighter, and hotter than later stars, which may explain why they ionized the hydrogen around them.
One possibility is the presence of radiation from an active galaxy nucleus, powered by the supermassive first black hole.
Joris Witztok, a professor at the University of Cambridge (United Kingdom), said: The large bubble of hydrogen ionized surrounding this galaxy may have been formed by stars that were much larger, hotter and brighter than those stars that appeared at later times, possibly representing the first generation.
Journal Reference
- Witstok, J., Jakobsen, P., Maiolino, R. et al. Witnessing the beginning of reionization by Lyman-a emissions at redshift 13 Nature 639: 897-901 (2020). DOI: 10.1038/s41586-025-08779-5
