Seyfert galaxy. Optical image of the Seyfert galaxy NGC 4945, an edge-on spiral galaxy in the constellation Centaurus. Seyfert galaxies have an unusually bright nucleus. The nucleus of this galaxy is a Seyfert type 2 nucleus, which does not appear unusually bright at visible wavelengths, but is a powerful emitter of infrared radiation. The power source for a Seyfert nucleus is thought to be a large black hole. A dark band of dust is seen running from upper left to centre in this galaxy.