By Ron Cowen
Astronomers have discovered the first example of a trio of quasars, the brilliant beacons of light that seem to be fueled by supermassive black holes at the centers of galaxies. The triplet adds to earlier evidence that supermassive black holes and galaxies grow in lockstep.
George Djorgovski of the California Institute of Technology in Pasadena and his colleagues began their study by examining a distant quasar called LBQS 1429-008. Another team had found the quasar in 1989 and soon after detected a nearby spot that could have been either a companion quasar or a cosmic mirage. According to Einstein’s general theory of relativity, the gravity of a massive foreground galaxy can act as a lens, splitting the light from a background body, such as a quasar, into two or more images.