A Close Encounter Between Galaxies

Astronomers have recently completed a large survey—known as the Cosmic Evolution Survey, or COSMOS—of the sky using some of the powerful telescopes both on the ground and in space. Researchers wanted to test whether close encounters between two galaxies trigger activity in the supermassive blackholes at their centers. The two galaxies seen here are just samples from the thousands of galaxies studied. Chandra data were key because the X-rays could pinpoint just how active the black holes were. It turns out that the black holes within these galaxies are, in fact, growing more rapidly if they are in the early stages of an encounter with another galaxy.