A Dancing Ancient Galactic Disk at a Peak of Star Formation ～Press release from Australian National University～

An international research team, led by Dr. Takafumi Tsukui from Australian National University, investigated the detailed gas movements in the galaxy BRI 1335-0417, a galaxy actively forming stars when the Universe was only 10% of its current age, using the ALMA (Atacama Large Millimeter/submillimeter Array) Telescope in Chile. The team reveals vertically oscillating waves (akin to seismic waves) forming in the flat disk structure of the galaxy. The vertically oscillating motions of the gas disk are caused by an external source, either from new gas streaming into the galaxy or by coming into contact with other smaller galaxies. Both possibilities would bombard the disk with new fuel for star formation. Additionally, the study of the gas distribution reveals a bar-like structure in the disk. Galactic bars are part of some galaxies, like our Milky Way, and can disrupt gas within galaxies and transport it towards the galaxy’s centre. The bar discovered in BRI 1335-0417, is the most distant such structure known. Together, these results reveal the dynamic growth of a young galaxy actively forming stars in the early Universe.

Simulation by Bland-Hawthorn and Tepper-Garcia illustrates a galaxy disk being disturbed, leading to the propagation of a seismic ripple throughout the disk.

(Credit: Bland-Hawthorn and Tepper-Garcia, University of Sydney).

This research was published as “Detecting a disk bending wave in a barred-spiral galaxy at redshift 4.4”
by Takafumi Tsukui et al. in the peer-reviewed journal Monthly Notices of the Royal Astronomical Society on 22 of December 2023.
Takafumi Tsukui, Emily Wisnioski, Joss Bland-Hawthorn, Yifan Mai, Satoru Iguchi, Junichi Baba, Ken Freeman:
“Detecting a disk bending wave in a barred-spiral galaxy at redshift 4.4”, MNRAS　https://doi.org/10.1093/mnras/stad3588

Press release from Australian National University:
https://reporter.anu.edu.au/all-stories/astronomers-detect-seismic-ripples-in-ancient-galactic-disk