A collection of Hubble space telescope images shows galaxies that host quasars.
According to NASA, ever since quasars were first discovered in 1963 "astronomers have been trying to crack the mystery of how these compact dynamos of light and other radiation, which lie at the outer reaches of the universe, produce so much energy. Quasars are no larger than our solar system but outshine galaxies of hundreds of billions of stars. These light beacons have left trails of evidence and plenty of clues, but scientists have only just begun to understand their behavior. Astronomers using Hubble tracked down the 'homes' of quasars, proving that these dynamos reside in the centers of galaxies."