The dual quasar known as SDSS J141637.44+003352.2, as imaged by the Subaru Telescope and Gemini North in Hawaii. The W.M. Keck Observatory provided spectroscopic confirmation of material swirling around each object at thousands of kilometres per second that’s indicative of supermassive black holes. Image: Silverman et al.
All large galaxies, including the Milky Way, are believed to harbour supermassive black holes in their cores. Some are relatively quiescent, but others generate enormous amounts of radiation, outshining their host galaxies as material is pulled in and heated to extreme temperatures. Such active galaxies are known as quasars.
Galaxy mergers across the cosmos are not rare, but what about quasars? As it turns out, very rare indeed.
Observations by the Subaru Telescope, the W.M. Keck Observatory and the Gemini North telescope in Hawaii indicate just 0.3 percent of all known quasars feature two supermassive black holes in ongoing galactic collisions. They are known as luminous dual quasars.
“In spite of their rarity, they represent an important stage in the evolution of galaxies, where the central giant is awakened, gaining mass, and potentially impacting the growth of its host galaxy,” said Shenli Tang, a graduate student at the University of Tokyo and co-author ...