File:Swift Survey Finds Smoking Gun of Black Hole Activation.webm

English: Swift Survey Finds 'Smoking Gun' of Black Hole Activation. Astronomers using X-ray data from an ongoing survey by NASA's Swift satellite have solved a decades-long mystery. Why, when most galaxies host giant black holes in their centers, do only about one percent of them emit vast amounts of energy?

The new findings confirm that the black holes "light up" when galaxies collide -- and may offer insight into the future behavior of the black hole in our own galaxy.

The intense emission from galaxy centers, or nuclei, arises near a supermassive black hole containing between a million and a billion times the sun's mass. Giving off as much as 10 billion times the sun's energy, some of these active galactic nuclei (AGN) -- a class that includes quasars and blazars -- are the most luminous objects in the universe.

This simulation follows the collision of two spiral galaxies that harbor giant black holes. The collision merges the black holes and stirs up gas in both galaxies. The merged black hole gorges on the feast and lights up, forming an active galactic nucleus called a quasar and creating a "wind" that blows away much of the galaxy's gas.