How quasars shut down star formation in the early universe‎

Supermassive black holes lurk at the centers of massive galaxies, including our own Milky Way. Puzzlingly, supermassive black holes more than a billion times the mass of the sun appear to exist just a few hundred million years after the Big Bang, when the universe was less than 5% of its current age. As interstellar gas spirals towards such black holes, it accelerates to extreme speeds, heats up, and emits intense radiation across the electromagnetic spectrum, creating a "quasar."