11 billion years old evidence of a cosmic hit-and-run: DAWN member discovers oldest known Galaxy Ring
Artist James Josephides trying to depict the formation of a galactic ring in this video sponsored by Nature:
Astronomers (including DAWN affiliate Claudia Lagos) find the hitherto most distant "ring galaxy".
Galaxies come in many shapes. One of the most peculiar types are ring galaxies, comprising only one out of 10,000 galaxies. How they form is not fully understood, but could be through either internal processes, or collisions with other galaxies.
In the past, when galaxies were closer to each other, collisions might be thought to be more important than internal processes, but this study suggests otherwise. The study did however find evidence for one cosmic collision, leaving a 33,000 light-year big hole in the center.
You can find the paper, published in Nature here.