Consider M60-UCD1, an ultra-compact dwarf galaxy located about 55 million light-years from Earth in the Virgo cluster. Despite its diminutive stance, the galaxy appears to harbor a supermassive black hole, one more fitting in a galaxy 80 times bigger.
The discovery may help resolve a long-standing mystery about ultra-compact dwarf galaxies, which are densely packed, spherical conglomerations of stars.
Scientists suspect these galaxies are the centers of what were once much larger galaxies that were striped of stars by passing neighbors. After the raid, the dense center cluster and its supermassive black hole were all that remained.
“There are quite a few of these ultra-compact dwarf galaxies and people have debated the nature of these objects for a long time. Are they just really, really massive star clusters -- because that’s really what they look like -- or are they the stripped nuclei of galaxies? This one is the first clear case that it is a striped galaxy nucleus,” University of Michigan astronomer Amy Reines told Discovery News.
The discovery also means that the local universe may be teeming with many more supermassive black holes than previous surveys suggest.
“This gives us a whole new home for black holes that we never knew existed before,” Reines said.
M60-UCD1 showed up on astronomer’s proverbial radar screens by an unusual X-ray emission.
“That could be a sign of a weakly accreting, really massive black hole,” said lead researcher Anil Seth, with the University of Utah. “But it also could be a stellar-mass black hole that’s rapidly accreting, or a neutron star.”
“It was an intriguing possibility,” Seth told Discovery News.
Read more at Discovery News
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