(ORDO NEWS) — A week after the world premiere of his first images, the James Webb Space Telescope potentially discovered a galaxy that existed 13.5 billion years ago. So said the scientist who analyzed the data.
The galaxy known as GLASS-z13 dates to about 300 million years after the Big Bang, about 100 million years earlier than anything previously identified, Rohan Naidoo of the Harvard Center for Astrophysics told AFP.
“We are potentially seeing the most distant starlight we have ever seen,” he said.
The further away objects are from us, the longer it takes for their light to reach us. Thus, to look into the distant universe is to look into the distant past.
Although GLASS-z13 existed in the earliest era of the universe, its exact age remains unknown, as it could have formed at any time during the first 300 million years.
GLASS-z13 has been detected in so-called “preliminary” data from the orbiting observatory’s main thermal imager, called NIRcam, but the discovery was not revealed in the first set of images released by NASA last week.
Translated from infrared to visible light, the galaxy appears as a blob of red with white in the center, part of a larger image of deep space called the “deep field”.
Naidu and a team of 25 astronomers from around the world submitted their results to a scientific journal.
At the moment, the study is hosted on the “preprint” server, so it has not yet been peer-reviewed, but it has already caused a sensation among the world astronomical community.
“Many astronomical records have become unusable, and many others are at risk,” wrote NASA Chief Scientist Thomas Zurbuchen.
“Yes, I tend to rejoice only when science gives a clear expert opinion. But it looks very promising,” he added.
Naidoo said that another group of astronomers led by Marco Castellano who worked with the same data came to similar conclusions, “so that gives us confidence.”
“More work to be done”
One of Webb’s biggest strengths is his ability to find the earliest galaxies that formed after the Big Bang 13.8 billion years ago.
Because they are so far from Earth, by the time their light reaches us, it has been stretched due to the expansion of the universe and shifted into the infrared region of the light spectrum, which Webb is able to detect with unprecedented clarity.
Naidoo and his colleagues looked at these infrared data from the distant universe looking for signatures of very distant galaxies.
Below a certain threshold wavelength of infrared radiation, all photons – bunches of energy – are absorbed by the neutral hydrogen of the Universe, which is located between the object and the observer.
Using data collected through different infrared filters aimed at the same region of space, they were able to determine where this photon dip occurs, from which they concluded that these most distant galaxies exist.
“We looked at all the early data on galaxies with this very bright feature, and these two systems had the most similarity,” said Naidoo.
One of them is GLASS-z13, and the other, less ancient, is GLASS-z11.
“There is strong evidence, but there is still a lot to be done,” Naidoo said.
Specifically, the team wants to ask Webb’s managers for time to run spectroscopy an analysis of light that reveals detailed properties to measure its exact distance.
“Right now, our guess at distance is based on what we don’t see it would be great to have an answer for what we see,” Naidoo said.
However, the team has already discovered surprising properties.
For example, the galaxy has a mass of a billion suns, which is “potentially very surprising, and we don’t fully understand it,” given how soon after the Big Bang it formed, Naidoo said.
Launched last December and fully operational since last week, Webb is the most powerful space telescope ever built, and astronomers are confident it will usher in a new era of discovery.
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