Finding quasars: rare extragalactic objects are now easier to spot

A quasar - the most luminous persistent source of light in the universe (NASA provided elements of this image) - Astrophysicists have developed a new method for finding changing-looking quasars - important but extremely rare objects in deep space. Last updated on Tuesday 18 May 2021 - Astrophysicists from the University of Bath have developed a new method for pinpointing the whereabouts of extremely rare extragalactic objects. They hope their technique for finding 'changing-look quasars' will take scientists one step closer to unravelling one of greatest mysteries of the universe - how supermassive black holes grow. Quasars are believed to be responsible for regulating the growth of supermassive black holes and their host galaxies. A quasar is a region of spectacular luminosity at the centre of a galaxy, powered by a supermassive black hole - the largest type of black hole, with a mass that exceeds that of our sun by millions or billions. There is a supermassive black hole at the centre of the Milky Way. Changing-look quasars switch rapidly between a state of high luminosity and one of low luminosity, and scientists are yet to work out why.