TEMPO.CO, Jakarta Just a week after showing the world its first images, the James Webb Space Telescope discovered the universe’s oldest candidate galaxy. The galaxy is known as GLASS-z13 and is estimated to have existed 300 million years after the Big Bang, or 13.5 billion years ago.
“We have the ability to observe this as the most distant stellar ray ever observed,” Rohan Naidu of the Harvard Center for Astrophysics said on Wednesday, July 20, 2022.
Naidu said, the farther the position of the star object from the earth, the longer the light reaches our eyes. So looking at the distant universe is like looking at the interior of the past.
For GLASS-z13, the specific age is not known, other than the alleged presence in the early period of the universe. The Milky Way could have formed at any time within the first 300 million years.
The GLASS-z13 galaxy was detected in so-called ‘early release’ data from the James Webb Space Telescope’s infrared camera sensor, NIRcam. But the data was not among the first five images sent by NASA’s replacement Hubble Telescope published last week.
When the data is translated into the visible light spectrum, the galaxy appears as a thick red dot with a white center. Its mass is estimated to be equal to that of a billion Suns.
Naidu and his colleagues – a team of 25 astronomers in total – have published their findings in scientific journals, although in a pre-printed version that has not been peer-reviewed. However, nevertheless, the image managed to create a conversation.
“Yes, I would welcome this discovery only after reviewing the scientific report. However, it looks very promising,” said NASA team leader Thomas Zurbuchen.
According to Naidu, another team of astronomical scientists led by Marco Castellano is also working on analyzing the same data. They, called Naidu, came to a similar conclusion. “So it gives us confidence,” Naidu said.
Measuring the age and exact distance of the oldest galaxies
One of the great things that the James Webb Telescope has promised is its ability to discover the first galaxies to form after the Big Bang, 13.8 billion years ago. Because of its location so far from Earth, the light reaching the observer’s eye is expanded by the expansion of the universe, and shifted to the infrared spectrum. This is where the capability of JWST comes in as it has a camera with NIR spectrum for detection with unprecedented clarity.
Naidu and his team then combed through infrared data containing recorded images of distant regions of the universe. They are looking for signs of very distant galaxies. “We found all the initial data for galaxies with very sharp signatures, and these are the two systems that carry the most signals to date,” Naidu said.
He pointed to GLASS-z13 and the other is GLASS-z11 which is not as old as the first. “This is solid evidence but there is still work to be done,” he said.
Specifically, Naidu revealed, the team wanted to ask the James Webb telescope manager to perform spectroscopic measurements, or light analysis, to more accurately measure distances. “Right now, our guesses are based on what we can’t see. It would be better if we answer for ourselves what we see,” Naidu said.
Science Alert, Space