Image via WikipediaSPACE.com -- Ginormous Black Hole May Solve Longstanding MysteryA pipsqueak galaxy nearby that's forming stars at a walloping rate appears to have a ginormous black hole in its center, a new study suggests.
The find is surprising, because dwarf galaxies like this usually don't host supermassive black holes. That this one does could help solve a cosmic conundrum: Which comes first — the black hole or the galaxy?
Many large galaxies — such as our own Milky Way — contain supermassive black holes in their centers. Scientists have wondered if these black holes form initially, and then galaxies build up around them — or vice versa.
Bulge-lessThe new discovery, of a black hole containing the mass of more than a million suns inside the nearby dwarf galaxy Henize 2-10, finally hints at an answer. [New photo of Henize 2-10]
Henize 2-10 lacks a bulge — a dense collection of stars that exists at the center of most spiral galaxies. Usually, the mass of a galaxy's bulge directly correlates with the mass of its central black hole. Some researchers thought a galaxy had to already have a bulge before a black hole could form.
"This definitely suggests the black hole comes first, because Henize 2-10 is a very low-mass dwarf galaxy without a detectable bulge, yet it does already have a supermassive black hole sitting there," said study leader Amy Reines, a graduate student at the University of Virginia. "So the implication is you don't have to have a bulge to form a black hole."
Yet more research will be needed to determine if this is the usual case, or if Henize 2-10 is just an oddball.
"This result suggests we need to look at more dwarf galaxies similar to Henize 2-10, because right now we just don't know if this a rare case or if other galaxies like it have their own black holes," Reines told SPACE.com.
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