CHAMPAIGN, Ill. — NASA’s Hubble Space Telescope is seeing double, uncovering two very close pairs of quasars that existed 10 billion years ago. The objects are close together because astronomers believe they resided in a pair of merging galaxies.

Research led by University of Illinois Urbana-Champaign astronomy and National Center for Supercomputing Applications professor Yue Shen offers a new way to probe collisions among galaxies in the early universe and the pairing of their supermassive black holes. The new study is published in the journal Nature Astronomy.

Quasars are beacons of intense light from the centers of galaxies that can outshine their entire galaxies. Powered by supermassive black holes, they feed on infalling matter and unleash a torrent of radiation.