James Webb Telescope: Dead galaxy discovered in the young cosmos

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Galaxies like JADES-GS-z7-01-QU, marked here, are very rare

Photo: JADES Collaboration / dpa

Already 700 million years after the Big Bang 13.8 billion years ago, stars suddenly stopped forming in a small galaxy.

This is shown by observations by an international research team using the James Webb space telescope.

They have discovered the earliest quiet galaxy in the cosmos to date - also called a dead galaxy.

The previous record was about 1.2 billion years after the Big Bang.

Experts had not expected such a dead galaxy so early in the early cosmos.

However, it is conceivable that stars were formed there again in a later epoch of cosmic development, according to the scientists in the journal Nature.

Astronomers don't know why star formation in Jades-GS-Z7-01-QU abruptly stopped, but they have a few theories.

A look into the distance is also a look into the past

There are many regions in our Milky Way where gas clouds often condense and new stars are constantly being formed.

But that's not the case everywhere - there are also quiet galaxies without significant star formation.

Astrophysicists do not yet know why this difference exists and since when in cosmic history.

“Direct observation of quiet galaxies in the early universe is of immense importance for our understanding of the formation and evolution of galaxies,” explain Tobias Looser from the University of Cambridge in Great Britain and his colleagues.

The team used the James Webb Space Telescope to look for galaxies at very great distances.

In astronomy, a look into the far distance is also a look into the cosmic past: If the light from a galaxy takes ten billion years to reach Earth, researchers see this star system as it looked ten billion years ago.

Short phase of vigorous star formation

The light from the galaxy now discovered by the team and cataloged under the name Jades-GS-Z7-01-QU takes 13.1 billion years to reach Earth.

The researchers looked into an epoch in which the universe was just 700 million years old.

As Looser and his colleagues report, the galaxy is emitting radiation that indicates a short phase of vigorous star formation.

Looser and his colleagues speculate that perhaps more gas was built up in the stars than could flow in.

Or star formation was so explosive that the energetic radiation from the hot young stars blew the gas out of the galaxy.

Or perhaps there was a burst of radiation from a large black hole at the center of the system that literally stopped star formation.

The low total mass of Jades-GS-Z7-01-QU is also astonishing to astronomers: with around 500 million solar masses, it is similar in size to the Small Magellanic Cloud, a satellite galaxy of the Milky Way.

All of the quiet galaxies known to date in the young cosmos are significantly larger, with over ten billion solar masses.

It is possible that the galaxy's low mass makes it particularly sensitive to feedback effects that can stop the formation of stars, the researchers said.

"In the early cosmos, everything seems to have happened faster and more dramatically," says Looser, "perhaps galaxies back then also switched more quickly between phases of star formation and quiet phases."

fzs/dpa