Astronomers have detected a powerful shockwave in Stephan's Quintet, a group of five galaxies colliding at 2 million mph. The collision is likened to a "sonic boom from a jet fighter" and has re-energized the plasma and gas in the system.

Source: https://www.livescience.com/space/astronomers-spot-1-of-the-most-powerful-sonic-booms-in-the-universe-as-massive-galaxy-crashes-into-its-neighbors