Massive Space Structure May Have Been Left by Galactic 'Intruder,' Astronomers Say

[Jilly_in_VA]

Scientists have discovered an unexplained structure made of hydrogen gas that stretches for nearly two million light years near a famous group of interacting galaxies, according to a new study.

The strange gas trail may have been formed by an “intruder” galaxy that collided with this galactic group, known as Stephan’s Quintet, about a billion years ago, but it will take more observations to understand the mystery of its formation.

Stephan’s Quintet is a spectacular group of five galaxies located about 300 million light years from Earth with a rich observational history. Named after Édouard Stephan, the astronomer who discovered it in 1877, the quintet was the first compact galaxy group ever spotted, and has since been imaged by countless observatories, including NASA’s James Webb Space Telescope, which is the most powerful observatory ever launched.

Now, scientists led by Cong Xu, a researcher at the National Astronomical Observatories in Beijing, have studied Stephan’s Quintet with the biggest single-dish telescope on Earth: China’s Five-hundred-meter Aperture Spherical radio Telescope (FAST). FAST was able to peer 100 times deeper into the galaxy group than past observations, revealing the never-before-seen gas structure that appears to be associated with the quintet, according to a study published on Wednesday in Nature.

Stephan’s Quintet “is unique among compact groups of galaxies,” said Xu and his colleagues in the study. “Observations have previously shown that interactions between multiple members, including a high-speed intruder galaxy currently colliding into the intragroup medium, have probably generated tidal debris.”

https://www.vice.com/en/article/qjkxbd/massive-space-structure-may-have-been-left-by-galactic-intruder-astronomers-say

Inner 10-year-old astronomer geeking out this morning!