An Ultracompact Dwarf Galaxy


M60-UCD1_by_HSTM60-UCD1 is an ultracompact dwarf galaxy. Half of its stellar mass is in the central sphere only 160 light years in diameter. It is probably the densest known galaxy with over one hundred stars per cubic light-year, and it is the smallest and least massive galaxy known to host a central black hole. It is also the most massive ultracompact dwarf galaxy known. It is also one of the oldest galaxies in the universe.

Image Credit: NASA

M60-UCD1


m60The densest galaxy in the nearby Universe may be this galaxy known as M60-UCD1. It is located near a massive elliptical galaxy NGC 4649, also called M60, about 54 million light years from Earth. Packed with an extraordinary number of stars, M60-UCD1 is an “ultra-compact dwarf galaxy”. It was discovered with the Hubble Space Telescope and follow-up observations were done with the Chandra X-ray Observatory and ground-based optical telescopes. It is the most luminous known galaxy of its type and one of the most massive, weighing 200 million times more than our Sun.

This composite image shows the region near M60. Data from the Chandra X-ray Observatory are pink and data from the Hubble Space Telescope are red, green and blue. The Chandra image shows hot gas and double stars containing black holes and neutron stars and the Hubble image reveals stars in M60 at the right edge of the frame.

Image Credit: NASA