Newly discovered Milky-Way-like rotating disc galaxy is the most distant and oldest of its type found in the universe about 700 million years after Big Bang

Amazing stuff! This study seems to challenge some prevailing theories about early galaxy formation.

"... The galaxy in question is dubbed REBELS-25. It is at a red shift of z=7.31, which means that it is from a time when the universe was only 700 million years old. The earliest galaxies ever seen are only a few hundred million years older. ...

This odd galaxy has stumped astronomers because it shows evidence of an ordered structure and rotation. It may even have a central elongated bar and spiral arms, though further observation is needed to confirm these structures.

This is in contrast to the small, messy, lumpy and chaotic norm for galaxies of a similar age. ..."

"... The rotation and structure of REBELS-25 were revealed using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, in which the European Southern Observatory (ESO) is a partner. ... astronomers found REBELS-25 to be the most distant strongly rotating disc galaxy ever discovered. The light reaching us from this galaxy was emitted when the Universe was only 700 million years old — a mere five percent of its current age (13.8 billion) — making REBELS-25’s orderly rotation unexpected. ..."

"Researchers have discovered the most distant Milky-Way-like galaxy yet observed. Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old. This is surprising since, according to our current understanding of galaxy formation, such early galaxies are expected to appear more chaotic. The rotation and structure of REBELS-25 were revealed using the Atacama Large Millimeter/submillimeter Array (ALMA). ..."

From the abstract (contains graphics, which were not copied):

"We present high resolution (∼0.14” = 710 pc) ALMA [CII] 158μm and dust continuum follow-up observations of REBELS-25, a [CII]-luminous (L[CII] = (1.7 ± 0.2) × 109L⊙) galaxy at redshift z = 7.3065 ± 0.0001. These high resolution, high signal-to-noise observations allow us to study the sub-kpc morphology and kinematics of this massive (⁠⁠) star-forming (SFR⁠) galaxy in the Epoch of Reionisation. By modelling the kinematics with 3DBAROLO, we find it has a low velocity dispersion (⁠ km s−1) and a high ratio of ordered-to-random motion (⁠⁠), indicating that REBELS-25 is a dynamically cold disc. Additionally, we find that the [CII] distribution is well fit by a near-exponential disc model, with a Sérsic index, n, of 1.3 ± 0.2, and we see tentative evidence of more complex non-axisymmetric structures suggestive of a bar in the [CII] and dust continuum emission. By comparing to other high spatial resolution cold gas kinematic studies, we find that dynamically cold discs seem to be more common in the high redshift Universe than expected based on prevailing galaxy formation theories, which typically predict more turbulent and dispersion-dominated galaxies in the early Universe as an outcome of merger activity, gas accretion and more intense feedback. This higher degree of rotational support seems instead to be consistent with recent cosmological simulations that have highlighted the contrast between cold and warm ionised gas tracers, particularly for massive galaxies. We therefore show that dynamically settled disc galaxies can form as early as 700 Myr after the Big Bang."

Newly discovered rotating disc galaxy is most distant of its type found in the universe

Space oddity: Most distant rotating disc galaxy found (original news release by Leiden University) "Researchers have discovered the most distant Milky-Way-like galaxy yet observed. Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old. This is surprising since, according to our current understanding of galaxy formation, such early galaxies are expected to appear more chaotic. Leiden astronomers Lucie Rowland and Jacqueline Hodge tell about their discovery."

Space oddity: Most distant rotating disc galaxy found (original news release by ALMA)

REBELS-25: Discovery of a dynamically cold disc galaxy at z = 7.31 (open access)

This image shows the galaxy REBELS-25 as seen by the Atacama Large Millimeter/submillimeter Array (ALMA), overlaid on an infrared image of other stars and galaxies. The infrared image was taken by ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA). In a recent study, researchers found evidence that REBELS-25 is a strongly rotating disc galaxy existing only 700 million years after the Big Bang. This makes it the most distant and earliest known Milky Way-like galaxy found to date.

This image of the galaxy REBELS-25, taken by the Atacama Large Millimeter/submillimeter Array (ALMA), shows how cold gas is distributed in the galaxy and exhibits hints of an elongated bar structure at its center.