Astronomers observe seismic-like ripples in oldest known spiral galaxy

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, a team of astronomers has observed seismic-like ripples in the ancient galactic disk of BRI 1335-0417, the oldest and furthest known spiral galaxy at over 12 billion years old. This discovery marks the first time such phenomena have been detected in an early distant galaxy.

The study, led by Dr Takafumi Tsukui, sheds light on the complex and mysterious processes that governed the formation and evolution of galaxies in the early universe.

This unprecedented observation showcases a vertically oscillating disk movement similar to ripples on a pond. The researchers attribute this movement to external influences like incoming gas or interactions with smaller galaxies, both crucial for star formation.

"Gas is a key ingredient for forming stars and can give us important clues about how a galaxy is actually fuelling its star formation," said Dr Tsukui.

The study also uncovers a bar-like structure within BRI 1335-0417, representing the most distant of its kind ever observed. This bar plays a significant role in transporting gas towards the center of the galaxy.

The rapid star formation rate of this ancient galaxy is a few hundred times faster than in modern galaxies like our home galaxy, the Milky Way. Understanding the mechanisms behind this rapid rate is crucial, particularly considering the rarity of spiral structures in early universes and the lingering mysteries surrounding their formation.

ALMA, comprising 66 high-precision antennas, was instrumental in this discovery, providing scientists with a snapshot of the Universe when it was just 10 percent of its current age.

"Early galaxies have been found to form stars at a much faster rate than modern galaxies. This is true for BRI 1335-0417, which, despite having a similar mass to our Milky Way, forms stars at rate a few hundred times faster. We wanted to understand how gas is supplied to keep up with this rapid rate of star formation," said co-author Associate Professor Emily Wisnioski.