Tiny Dwarf Galaxy Houses Supermassive Black Hole Larger Than the Milky Way's (VIDEO)

A tiny galaxy, an ultracompact dwarf, has a feature that astronomers didn't expect to find. It turns out that this small galaxy harbors a supermassive black hole, suggesting that these huge black holes may be far more common than previously thought.

"It is the smallest and lightest object that we know of that has a supermassive black hole," said Anil Seth, lead author of the new study, in a news release. "It's also one of the most black hole-dominated galaxies known."

The researchers first spotted the tiny galaxy with the help of the Gemini North 8-meter optical-and-infrared telescope in Hawaii in addition to photos taken by the Hubble Space Telescope. Investigating the galaxy, named M60-UCD1, a bit further, they found that it possessed a black hole with the mass equivalent to 21 million suns. The question was how did the black hole form in such a tiny galaxy.

The researchers may have an answer. They believe that it's possible the dwarf galaxy may be a stripped remnant of a larger galaxy that was torn apart during a collision with another galaxy. This would explain why the black hole is so large while the galaxy itself is so small.

"We don't know of any other way you could make a black hole so big in an object this small," said Seth. "There are a lot of similar ultracompact dwarf galaxies, and together they may contain as many supermassive black holes as there are at the centers of normal galaxies."

In fact, the black hole is actually five times larger than our own Milky Way's supermassive black hole. It's a stunning 15 percent of the dwarf galaxy's total mass of 140 million suns; this, in particular, is unusual since the Milky Way is 500 times larger than the dwarf galaxy and more than 1,000 times heavier.

Yet what's really interesting is the fact that this ultracompact dwarf galaxy may eventually collide with and be absorbed by the galaxy M60. Exactly when that might happen, though, is a cause for uncertainty.

"Eventually, this thing may merge with the center of M60, which has a monster black hole in it, with 4.5 billion solar masses-more than 1,000 times bigger than the supermassive black hole in our galaxy," said Seth. "When that happens, the black hole we found in M60-UCD1 will merge with that monster black hole."

The findings reveal a bit more about supermassive black holes and may actually be far more common than previously thought. It also shows a bit more about how ultracompact dwarf galaxies form; they may just be the leftover remnants of much larger galaxies.

The findings are published in the journal Nature.

You can see a video simulation of galaxy M60's gravity stripping the tiny dwarf galaxy's outer segments in the video below, courtesy of Vimeo.

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