Galactic collision creates huge particle collider

BOSTON — A galactic pileup 5 billion light-years away is building a powerful particle accelerator, up to a million times as strong as Earth’s mightiest, the Large Hadron Collider. New images from the Very Large Array and Chandra X-ray Observatory, presented June 3 at the American Astronomical Society meeting, reveal a colossal collision driving a fountain of charged particles 2.5 million light-years into intergalactic space.

Galaxy clusters are the largest gravitationally bound structures in the universe, said Reinout van Weeren of the Harvard-Smithsonian Center for Astrophysics at a press conference. Astronomers think that large clusters, which house thousands of galaxies, build up over billions of years as smaller clusters collide.  

The newly imaged jet sits at the heart of what van Weeren called “the most complex cluster collision known.” Four smaller clusters with a total mass of 3 million billion suns are crashing together. The Chandra images show gas between the galaxies squeezed and heated to 100 million degrees Celsius. Radio maps from the Very Large Array reveal the particle fountain in the hot gas. The jet could provide information about how such large clusters are built.