Hubble image of Arp 116 (annotated)
This image shows Arp 116, which is composed of a giant elliptical galaxy known as Messier 60, and a much smaller spiral galaxy, NGC 4647. Also included in the image is an annotated pointer to their even smaller neighbour M60-UCD1.
Lying about 50 million light-years away, M60-UCD1 is a tiny galaxy with a diameter of 300 light-years – just 1/500th of the diameter of the Milky Way! Despite its size it is pretty crowded, containing some 140 million stars.
An international team of astronomers have found a supermassive black hole at the centre of M60-UCD1 with the mass of 20 million Suns.
The original version of this image can be found here.