It is believed that the intergalactic medium’s gas was ionized by ultraviolet light from early galaxies. Due to those galaxies’ faintness and the redshift of their optical light into the infrared, there aren’t many observational restrictions on this period.
A team led by the University of Minnesota Twin Cities peered more than 13 billion years into the past using ground-breaking images from the James Webb Space Telescope to find a singular, tiny galaxy that produced new stars at an incredibly high rate for its size. Around 500 million years after the Big Bang, a galaxy among the smallest ever found at this distance was spotted, which may provide astronomers with new information about early universe galaxies.
Patrick Kelly, senior author of the paper and an assistant professor at the University of Minnesota School of Physics and Astronomy, said, “This galaxy is far beyond the reach of all telescopes except the James Webb, and these first-of-their-kind observations of the distant galaxy are spectacular. Here, we’re able to see most of the way back to the Big Bang, and we’ve never looked at galaxies when the universe was this young in this level of detail. The galaxy’s volume is roughly a millionth of the Milky Way’s, but we can see that it’s still forming the same numbers of stars each year.”
Due to a phenomena known as gravitational lensing, where mass, such as that in a galaxy or galaxy cluster, bends and magnifies the light, the researchers were able to discover and examine this new, tiny galaxy. This faint background galaxy was magnified by a galaxy cluster, making it appear 20 times brighter than it would have otherwise.
The team then used spectroscopy to measure how far away the galaxy was. They also determined some of its physical and chemical properties.
Hayley Williams, the first author of the paper and a Ph.D. student at the Minnesota Institute for Astrophysics, said, “The galaxies that existed when the Universe was in its infancy are very different from what we see in the nearby Universe now. This discovery can help us learn more about the characteristics of those first galaxies, how they differ from nearby galaxies, and how the early galaxies formed.”
Scientists noted, “The James Webb telescope can collect about ten times as much light as the Hubble Space Telescope and is much more sensitive at redder, longer wavelengths in the infrared spectrum. This allows scientists to access an entirely new window of data.”
Williams said, “The James Webb Space Telescope has this amazing capability to see far into the universe. This is one of the most exciting things about this paper. We see things that previous telescopes would have ever been able to capture. It’s getting a snapshot of our universe in the first 500 million years of its life.”
- Hayley Williams, Patrick Kelly, et al. A magnified compact galaxy at redshift 9.51 with strong nebular emission lines. Science. DOI: 10.1126/science.adf5307