Quasars are compact, luminous objects powered by super-massive black holes.
They are not a distinct class of objects but rather a phase that young galaxies go through when the black holes at their centers pull in surrounding matter at a high rate. The newly discovered quasar has a redshift of 5.8, which means that astronomers are seeing light that left its source when the universe was in its infancy, less than a billion years old. Past quasar surveys have included a smaller, less uniform selection of objects.