Galaxy Collision Switches on Black Hole This composite image of a collision between two galaxies NGC and IC contains Xrays from Chandra purple infrared data from Spitzer red and optical data from the Very Large Telescope red green and blue When combined these data reveal that IC the small galaxy at the top of the image is feeding its supermassive black hole by drawing cold gas from its partner galaxy the spiral NGC These two galaxies are in the process of merging allowing the reservoir of fuel to be supplied to the growing black hole
