The Galaxy Potentially Discovered by JWST Might Be the Earliest We’ve Ever Observed

Astronomers might have found galaxies that formed very early in the universe, approximately 200 million years apart from their closest counterparts, but they caution that alternative explanations could exist.

Giovanni Gandolfi from the University of Padua, along with his team, examined data from the James Webb Space Telescope (JWST) in search of distant cosmic formations from the universe’s 13.8 billion-year timeline.

The greater the distance of a galaxy from Earth, the longer it takes for its light to reach us, and it will be redshifted due to the universe’s expansion.

Until now, the earliest confirmed galaxy identified by JWST, named Mom-Z14, has a redshift of 14.4, indicating that it has been moving toward us since the universe was just 280 million years old. Gandolfi and his colleagues, however, have reported finding 32 intriguing objects with redshifts, placing them at a time when the universe was merely 90 million years old. They have named this discovery Capotauro after the Italian mountains.

“Capotauro could represent the most distant galaxy we’ve encountered,” states Gandolfi.

The team derived their conclusion from observing minor fluctuations in a deep JWST survey of the sky that resemble a distant galaxy. By utilizing various filters on the telescope, they were able to determine the redshift of the light emitted by the galaxy, arriving at a count of 32.

If validated, this object might represent a very young galaxy in formation, or potentially a primitive black hole enveloped by a dense atmosphere.

Nonetheless, this presumed galaxy appears uncommonly bright, akin to those observed in later redshift instances like Mom-Z14, suggesting it has a mass approximating a billion times that of the Sun.

For a galaxy to reach such mass, its efficiency in converting gas into stars must be near 100%, according to Nicha Reese Chawarit from the National Institute of Astronomy in Thailand, indicating that the stars cannot explode. Modelling, however, suggests that achieving 10-20% or even lower is plausible. “I believe there’s something amiss,” she remarks.

If this is not a galaxy, Gandolfi and his team propose that the object could alternatively be a brown dwarf (a star that didn’t ignite). These alternative theories are also compelling, Gandolfi notes, particularly if it is a cold brown dwarf or distant planet, possibly 6000 light years away and at room temperature.

“It could represent one of the first substellar objects ever formed in our galaxy,” adds Gandolfi.

To confirm this, the team requires additional observing time on the JWST to precisely analyze the light from the object. Leethochawalit supports the notion that it may not be a galaxy but also states that such follow-up research could still be worthwhile.

“If it turns out to be a galaxy with a redshift of 32, then a lot of our previous assumptions might be entirely wrong,” she states.

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