Photo Credit: NASA, ESA, D. Coe, G. Bacon (STScI)
By Charles Q. Choi
Astronomers have just discovered the smallest known galaxy that harbors a huge, supermassive black hole at its core.
The relatively nearby dwarf galaxy may house a supermassive black hole at its heart equal in mass to about 21 million suns. The discovery suggests that supermassive black holes may be far more common than previously thought.
A supermassive black hole millions to billions of times the mass of the sun lies at the heart of nearly every large galaxy like the Milky Way. These monstrously huge black holes have existed since the infancy of the universe, some 800 million years or so after the Big Bang. Scientists are uncertain whether dwarf galaxies might also harbor supermassive black holes. [Watch a Space.com video about the new dwarf galaxy finding]
“Dwarf galaxies usually refer to any galaxy less than roughly one-fiftieth the brightness of the Milky Way,” said lead study author Anil Seth, an astronomer at the University of Utah in Salt Lake City. These galaxies span only several hundreds to thousands of light-years across, much smaller than the Milky Way’s 100,000-light-year diameter, and they “are much more abundant than galaxies like the Milky Way,” Seth said.
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