Actively growing supermassive black holes in centers of galaxies are common even in cosmic voids, the most rarefied and empty regions of the universe.

http://www.sciencedaily.com/releases/200...

A "slice" of about 700 million light-years across in the distribution of galaxies in the universe. Voids are marked as blue circles, and galaxies within as red dots. The image shows a void galaxy that harbors an actively accreting black hole in its center; such activity is revealed by its optical spectrum exhibiting emission spikes, characteristic of hot gases ionized by light emitted from matter swirling around a supermassive black hole. Other objects in the image are either in the foreground or background. (Credit: John Parejko, Danny Pan and Anca Constantin of Drexel University)
In a study of more than 1,000 void galaxies, using data from the Sloan Digital Sky Survey (SDSS-II), astronomers from Drexel and Widener Universities announced that the growth of these monster black holes – with masses millions to hundreds of millions times that of our sun – are found where galaxies are sparse and interact very little with each other. The researchers also found that the accretion of matter onto these void black holes is slower than in denser galactic environments.