Examples of some of the newly discovered double active nuclei. On the left are traditional astronomical "seeing limited" images from the Sloan Digital Sky Survey; the central box is shown expanded on the right, as observed with the Keck telescope and Adaptive Optics. (In one image, there is a further zoom-in on the central portion shown in the upper right.) Double active nuclei — each powered by a supermassive black hole — are easily discerned in the Keck images, which have the resolution similar to that of the Hubble Space Telescope, but are obtained from the ground using the Laser Guide Star Adaptive Optics technology, which removes the atmospheric blur.
S. G. Djorgovski, H. Fu, et al., Caltech