U of U Astronomer Discovers Smallest Known Galaxy With a Supermassive Black Hole

Sep 17, 2014

A University of Utah astronomer has discovered that there might be a lot more supermassive black holes in the universe than previously thought.

A supermassive black hole is a black hole that is at least a million times larger than the mass of the sun. They’re found at the center of most large galaxies, including our own Milky Way galaxy.

Anil Seth is a professor of Physics and Astronomy at the University of Utah. In a new study, he and his colleagues discovered one of these supermassive black holes somewhere they’ve never found one before, in an ultracompact dwarf galaxy.

“This is a galaxy that is about 1,000 times less massive than the Milky Way galaxy, about 500 times smaller than the Milky Way galaxy, and yet it has a black hole that’s about 5 times the black hole in our own galaxy,” he says.

This is the smallest galaxy ever to be found with a supermassive black hole. Seth says it’s important to study black holes because they help us understand how galaxies evolve over time. Finding such a big black hole at the center of this ultacompact galaxy helps solidify a theory that it is actually a remnant of a much larger galaxy that was stripped of its mass by another nearby galaxy.

“We don’t know of any way we could form such a big black hole in such a small object.”

Seth says this discovery greatly expands the number of objects they’ll look at that might have black holes.

“Cause we can say, OK, maybe that big globular cluster in Andromeda, maybe that’s the remnant of a dwarf galaxy and we can look for a black hole there,” he says.

Seth will be delivering a lecture on his latest findings and about black holes in general at the Clark Planetarium this Saturday at 7 p.m. 

Formation of Dwarf Galaxy M60-UCD1 from The University of Utah on Vimeo.