The typical standard candles had not formed at that time of the universe evolution. An active galaxy is a galaxy that is very far from our own galactic neighborhood, looks like a normal galaxy in the visible wavelengths, but looks quite extraordinary in other wavelengths such as UV, IR, and radio. The two types are called Seyfert galaxies and Radio galaxies. Seyferts look like normal spiral galaxies in visible light, but most of the light comes from the center of the galaxy, and is 10,000 times brighter than the Milky Way. The light from the galaxy is redshifted, showing that the distance to the galaxy is on the order of a few hundred Mpc.
Radio galaxies look like standard elliptical galaxies in visible light.
In radio light, however, they can have enormous radiation jets, lobes, or great halos surrounding the entire galaxy. They also have redshifts showing a distance of a few hundred Mpc. The active galaxies are powered by enormous supermassive black holes gobbling up large amounts of matter from a large accretion disk surrounding the black hole. This is not actually what is happening. What is really happening is that the universe has greatly expanded since the time that the photon was emitted by the quasar, enlarging the wavelength of the photon in the process.