Astronomers have found a supermassive black hole in an improbable place. The monster black hole is lurking inside one of the smallest and densest galaxies ever known. Called M60-UCD1, this dwarf galaxy is located about 54 million light years away from Earth. If you go inside this M60-UCD1 galaxy, you would see over a million stars with the naked eye in the night sky. By comparison, we can see only about 4,000 stars in the night sky from Earth.
Black hole in M60-UCD1 five times bigger than the one in Milky Way
The black hole at the center of this tiny galaxy has a mass of 21 million suns. That means its mass is five times bigger than the one at the center of our Milky Way galaxy. The black hole in our galaxy has a mass of four million suns, making up less than 0.01% of the Milky Way’s total mass. In contrast, the supermassive black hole at the center of M60-UCD1 is a whopping 15% of the galaxy’s total mass.
Findings of the study were published in the journal Nature on September 18. Astronomer Anil Chandra Seth of the University of Utah said the dwarf galaxy crams over 140 million stars in a diameter of 300 light years, just 1/500th of the diameter of Milky Way. Findings imply that there could be other compact galaxies, too, containing supermassive black holes.
Researchers used Hubble and Gemini to study the black hole
Researchers used NASA’s Hubble and the Gemini North 8-meter optical and infrared telescope on Hawaii to observe and measure the black hole’s mass. A black hole is an ultra-compact, gravitationally collapsed object having a gravitational pull so strong that even light can’t escape. The observation indicates that dwarf galaxies may be the stripped remnants of bigger galaxies that were torn apart during collisions.
Scientists believe that the M60-UCD1 was once a giant galaxy containing over ten billion stars. But its close encounter with the center of an even bigger galaxy, M60, caused the dark matter and stars in its outer part to get torn away and become part of M60. Researcher led by Seth said the M60-UCD1 may eventually merge with M60, which has its own supermassive black hole.