Astronomers say they have found the most distant galaxy ever observed


It’s a record that’s been broken multiple times in the past two years alone, and one we expect to see again soon.

Astronomers using the newly operational James Webb Space Telescope (JWST) have announced the discovery of what appears to be the most distant galaxy yet.

If that sounds familiar, it’s happened twice already this year. In April, astronomers announced their sighting of a galaxy in just a moment 330 million years after the Big Bang. Last month, in other JWST data, another was found at some point 300 million years after the Big Bang.

The new record holder, however, is stunning. Discovered in the darkness of the early Universe, it represents a time barely 235 million years after the big Bang …virtually a cosmic blink of an eye, against the backdrop of the 13.8 billion year old Universe.

The discovery of the candidate galaxy, named CEERS-93316, marks the beginning of something wonderful: Webb is about to throw the early universe wide open, giving us an unprecedented view of the dark and mysterious expanses at the start of , well, everything.

A paper led by astrophysicist Callum Donnan from the University of Edinburgh has been submitted to the Royal Astronomical Society Monthly Noticespending peer review, and is available on the arXiv pre-release server.

The first billion years after the Big Bang is of great interest to cosmologists. Meanwhile, the hot, quantum soup that filled the Universe after its appearance began to form everything: matter and antimatter and black matterstars and galaxies and dust.

Because light takes time to travel, any light reaching us from deep space represents an event deep in the past; so, in effect, light is a time machine for the far reaches of the Universe. But the early – really early – Universe is more difficult: it’s so far away that any light reaching us is very, very faint.

Moreover, the expansion of the Universe has stretched even the most energetic waves into dull rays closer to the infrared parts of the spectrum, making even the most visible objects difficult to read.

This makes detailed reconstructions from this era very difficult. Which is all the more unfortunate since it’s such a critical moment.

The era before the birth of the first stars was called the cosmic dawn. Beginning nearly 250 million years after the Big Bang, it filled the entire Universe with an opaque cloud of hydrogen atoms.

It was not until ultraviolet light from early stars and galaxies reionized charge-neutral hydrogen that the entire electromagnetic spectrum was able to spread.

Thanks to this epoch of reionization, about a billion years after the Big Bang, light was able to shine unhindered again.

Naturally, we want to know more about the youth of the Universe during this foggy time; how those first stars formed in the dawn clouds, how the galaxies came together, how supermassive black holes could form so quickly in the first hundreds of millions of years of existence. Looking back to those distant, hazy times is one of the main tasks Webb is designed for.

Webb can capture near infrared and infrared light, with the highest resolution of any telescope ever sent into space. It’s designed to excel at detecting these highly redshifted galaxies, so cosmologists can finally get a detailed look at what’s going on, if not at Cosmic Dawn, at least during reionization.

CEERS-93316, according to Donnan and his colleagues, must be at least fairly close to one of the very first galaxies after the Big Bang. The team ruled out other potential explanations for the faint red glow, and their analysis suggests that star formation in the candidate galaxy must have started between 120 and 220 million years after the Big Bang.

In order to confirm the identity of the object, however, follow-up spectroscopic observations will need to be undertaken. This would hopefully confirm the redshift; from there, the object could become the subject of further and more detailed study and help build a census of the earliest objects in the Universe.

If CEERS-93316 is a galaxy, it probably won’t be wearing the most distant galaxy ever sash for long. Even if CEERS-93316 doesn’t turn out to be such a distant galaxy, chances are we won’t have long to wait for Webb to discover an object that is.

Bring us those dark, red, distant treasures, Webb. We can’t wait.

The research was submitted to Royal Astronomical Society Monthly Noticesand is available on arXiv.



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