PASADENA, Calif., Jan. 12 (UPI) -- Sixteen close-knit pairs of super-massive black holes in merging galaxies have been discovered, U.S. astronomers reported Wednesday.
The black-hole pairs are a distance about a hundredth to a thousandth shorter than observed previously. That provides astronomers a chance to examine how the holes and their host galaxies merge, which is critical in understanding the evolution of the universe, the scientists said in a release.
They said their find was the largest population of such objects observed from a systematic search.
"This is a very nice confirmation of theoretical predictions," says S. George Djorgovski, professor of astronomy at the California Institute of Technology. "These close pairs are a missing link between the wide binary systems seen previously and the merging black-hole pairs at even smaller separations that we believe must be there."
If scientists' understanding of the universe's structure formation is correct, closer pairs of active nuclei must exist, said Adam Myers, a research scientist University of Illinois at Urbana-Champaign and a co-author.
The discovery was presented in Seattle Wednesday during the meeting of the American Astronomical Society, and was submitted for publication in the Astrophysical Journal.