TEMPO.CO, Jakarta – Just a week after its first images were shown to the world, the James Webb Space Telescope has discovered the oldest candidate galaxy in the universe. The galaxy is known as GLASS-z13 and is estimated to have formed 300 million years after the Big Bang, or been around for 13.5 billion years.

“We have the potential to see it as the most distant stellar ray that has ever been seen,” Rohan Naidu of the Harvard Center for Astrophysics said on Wednesday, July 20, 2022.

Naidu said that the farther the position of the star object is from Earth, the longer the light reaches our eyes. Thus, observing the distant universe is like looking inside the past.

For GLASS-z13, the specific age is not known, other than presumed presence in the early universe period. The galaxy could have formed at any time during the first 300 million years.

The galaxy GLASS-z13 was found in so-called “advance scatter” 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 Hubble Replacement Telescope released 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 at the equivalent of a billion suns.

Naidu and his colleagues – a team of 25 astronomers in total – have published their findings in scientific journals, albeit in a preprint version that has not been peer-reviewed. However, the image managed to create a conversation.

“Yes, I will only welcome this discovery after the scientific report has been peer reviewed. 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 that gives us confidence,” Naidu said.

Measure the exact age and distance of the oldest galaxies

One of the great promises of the James Webb Telescope is its ability to discover the first galaxies that formed after the Big Bang 13.8 billion years ago. Due to its location so far from Earth, the light that reaches the eye of the beholder has been enlarged by the expansion of the universe and shifted to the infrared spectrum. This is where JWST’s ability comes into play as it has a camera with an NIR spectrum to detect 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 extremely distant galaxies. “We searched for all the initial data for galaxies with very clear signatures, and these are the two systems that encounter the most signs by far,” Naidu said.

He pointed to GLASS-z13 and the second is GLASS-z11 which is not as old as the first. “It’s strong evidence but there’s still work to be done,” he said.

Specifically, Naidu revealed, the team wanted to ask telescope manager James Webb to perform spectroscopic measurements or light analysis to measure distances more accurately. “Right now our estimates are based on what we can’t see. It would be nice to have an answer to what we see for ourselves,” Naidu said.

SCIENTIFIC ALERT, SPACE