Seyfert galaxy. Optical image of the Seyfert galaxy NGC 4945 (upper centre), 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. The stars Xi 1 Centauri (upper right) and Xi 2 Centauri (lower left) are also seen.