Astronomers detect seismic ripples in ancient galactic disk

A new snapshot of an ancient, distant galaxy could help scientists understand how it formed and the origins of our Milky Way. BRI 1335-0417 is more than 12 billion years old and is the oldest and most distant known spiral galaxy in our universe.

Lead author Dr Takafumi Tsukui said the state-of-the-art telescope ALMA allowed them to observe this ancient galaxy in greater detail.

“Specifically, we are interested in how gas enters and moves through the Milky Way,” Dr. Tsukui said. “Gas is a key ingredient in star formation and can give us important clues about how galaxies actually contribute to the formation of their stars.”

In this case, the researchers were not only able to capture the motion of the gas surrounding BRI 1335-0417, but also revealed the first seismic waves to form in such an early galaxy.The study was published in Royal Astronomical Society monthly notices.

Galactic disks are flat objects made of rotating stars, gas and dust that move in a way not unlike ripples on a pond after a stone is thrown into it.

“The vertical oscillatory motion of the disk is caused by external sources, either new gas flowing into the galaxy or contact with other smaller galaxies,” Dr. Tsukui said. “Both possibilities would bombard the galaxy with new fuel to form stars.

“In addition, our study reveals bar-like structures in the disk. The galactic bar breaks up gas and transports it to the center of the galaxy. The bar found in BRI 1335-0417 is the most distant such structure known. Overall In general, these results show the dynamic growth of young galaxies.”

Because BRI 1335-0417 is so far away, its light takes longer to reach Earth. The images seen through telescopes today are a throwback to the early days of the Milky Way, when the universe was only 10% of its current age.

“It was found that early galaxies formed stars much faster than modern galaxies. The same is true for BRI 1335-0417, which despite having a similar mass to our Milky Way, formed stars hundreds of times faster,” Common said author Associate Professor Emily Wisniowski.

“We want to understand how gas is supplied to keep up with such rapid star formation.

“Spiral structures are rare in the early universe, and exactly how they formed remains unknown. This study also provides us with important information about the most likely scenario.

“While it’s impossible to directly observe the evolution of galaxies because our observations only give us a snapshot, computer simulations can help piece together the story.”