These active galactic nuclei are powered by accretion onto supermassive black holes.
A unique type of these objects that has absorption lines greater than a thousand kilometers per second in width is the BAL, or broad-asborption line, type. Intense gravitational lensing creates four images of one of these objects in the Einstein cross. These objects are useful for studying density fluctuations in the early universe because their radiation is absorbed by intergalactic clouds and galaxies, creating a (*) forest of lines blueward of their Lyman-alpha line. It's conjectured that these objects having their relativistic jets pointed at Earth explains blazars. These active galactic nuclei are powered by accretion onto supermassive black holes. For 10 points, what most energetic objects in the universe are also called quasi-stellar radio sources?
A unique type of these objects that has absorption lines greater than a thousand kilometers per second in width is the BAL, or broad-asborption line, type.
quasars [or quasi-stellar radio sources or QSOs until "quasi-stellar" is read]