middle of every galaxy http://www.spacetelescope.org/science/black_holes/ quasar « Black holes, quasars and active galaxies » telescopio espacial Hubble http://www.spacetelescope.org/science/black_holes/ active supermassive black holes Black holes, quasars and active galaxies active supermassive black holes quasar http://www.spacetelescope.org/science/black_holes/ « Black holes, quasars and active galaxies » supermassive black holes active supermassive black holes « Black holes, quasars and active galaxies » active supermassive black holes http://www.spacetelescope.org/science/black_holes/ active supermassive black holes