Wolfe Disk – ALMA telescope captures galaxy in the early universe

Hyperaxion May 21, 2020

A study published in the journal Nature reveals that the system emerged just 1.5 billion years after the Big Bang – well before what current models of galaxy formation predicted.

New observations with the Atacama Large Millimeter / submillimeter Array (ALMA) telescope in Chile, reveal the existence of a massive disk galaxy at the beginning of the Universe. According to an article, published in the journal Nature on Wednesday (20), the system emerged just 1.5 billion years after the Big Bang (which occurred 13.8 billion years ago).

ALMA telescope captures galaxy in the early universe
Artist impression of the Wolfe Disk, a massive rotating disk galaxy in the early universe. (Credit: NRAO/AUI/NSF, S. Dagnello).

Wolfe Disk

Galaxy DLA0817g, also called Wolfe Disk, after the late astronomer Arthur Wolfe, is the most distant rotating disk galaxy ever observed. According to astronomers, another fascinating aspect is that the galaxy rotates at 272 kilometers (169 mi) per second, a speed similar to that of the Milky Way.

The discovery of Wolfe Disk creates a challenge for many models of galaxy formation proposed by scientists. According to current models, systems like this are formed from fusions of smaller galaxies and hot clusters of gas and, for that reason, they could only have formed 6 billion years after the Big Bang.

The Wolfe Disk as seen with ALMA (right – in red), VLA (left – in green) and the Hubble Space Telescope (both images – blue). (Credit: ALMA – ESO/NAOJ/NRAO, M. Neeleman; NRAO/AUI/NSF, S. Dagnello; NASA/ESA Hubble).

The new finding, however, suggests that other processes may have interfered with the formation of galaxies at the beginning of the Universe. “We think the Wolfe Disk has grown primarily through the steady accretion of cold gas,” said Xavier Prochaska, co-author of the article, in a statement. “Still, one of the questions that remains is how to assemble such a large gas mass while maintaining a relatively stable, rotating disk.”

The researchers also noted that the rate of star formation on Wolfe Disk was at least ten times higher than in the Milky Way. “It must be one of the most productive disk galaxies in the early universe,” said Prochaska.

The team discovered the galaxy while examining the light from a more distant quasar. The light emitted by the quasar was absorbed as it passed through a huge reservoir of hydrogen gas around the Wolfe Disk, revealing it.

This indicates that, instead of looking for light emitted directly by the galaxies, they can use this method of “absorption” to detect fainter galaxies. “When our newest observations with ALMA surprisingly showed that it is rotating, we realized that early rotating disk galaxies are not as rare as we thought and that there should be a lot more of them out there,” noted Marcel Neeleman, co-author of the research.

Related topics:

ALMA Galaxies Milky Way Quasar

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