Supermassive black holes may be lurking everywhere in the universe, according to a recent study.
A near-record supermassive black hole discovered in a sparse area of the local universe indicates that these monster objects - this one equal to 17 billion suns - may be more common than once thought, according to University of California, Berkeley, astronomers.
Until now, the biggest supermassive black holes - those with masses around 10 billion times that of our sun - have been found at the cores of very large galaxies in regions loaded with other large galaxies.
The current record holder, discovered in the Coma Cluster by the UC Berkeley team in 2011, tips the scale at 21 billion solar masses and is listed in the Guinness Book of World Records.
The newly discovered black hole is in a galaxy, NGC 1600, in the opposite part of the sky from the Coma Cluster in a relative desert, said the leader of the discovery team, Chung-Pei Ma.
While finding a gigantic black hole in a massive galaxy in a crowded area of the universe is to be expected - like running across a skyscraper in Manhattan - it seemed less likely they could be found in the universe's small towns.
"Rich groups of galaxies like the Coma Cluster are very, very rare, but there are quite a few galaxies the size of NGC 1600 that reside in average-size galaxy groups," Ma said. "So the question now is, 'Is this the tip of an iceberg?' Maybe there are a lot more monster black holes out there that don't live in a skyscraper in Manhattan, but in a tall building somewhere in the Midwestern plains."
NGC 1600 suggests that a key characteristic of a galaxy with binary black holes at its core is that the central, star-depleted region is the same size as the sphere of influence of the central black hole pair, Ma said.
Images taken by the Hubble Space Telescope revealed that the center of NGC 1600 is unusually faint, indicating a lack of stars close to the black hole. A lack of stars close to the galactic center distinguishes massive galaxies from standard elliptical galaxies, which are much brighter in their cores.
"One dynamical footprint of a binary black hole is core scouring," Ma said.
This signature will help Ma and her colleagues refine the MASSIVE Survey and more quickly find the supermassive black holes in Earth's vicinity.
The study appears in the journal Nature.