A researcher at the University of Colorado, Boulder announced an extremely rare discovery at the 227th meeting of American Astronomical Society (AAS) on Tuesday: a galaxy with a pair of black holes, one of which appears to be on some sort of intergalactic diet.
According to the Associated Press, Julie Comerford, an assistant professor in the Department of Astrophysical and Planetary Sciences at the university, discovered the double-black hole system in a galaxy approximately one billion light years away.
That alone is a rare enough discovery, as thus far there have only been 12 galaxies confirmed to contain two black holes, but Comerford’s system is even more unusual, as one of the black holes is “significantly” smaller than the other and appears to be devoid of stars.
She discovered the unusual double-black hole galaxy—officially identified as SDSS J1126+2944—last year using the Hubble Space Telescope and NASA’s Chandra X-ray Observatory. While this is the fourth such galaxy discovered by Comerford, it’s by far the most unusual.
So what caused this unique double-back hole system?
Comerford believes that the thinner of the two black holes went on a crash diet of sorts, if you will: It lost its mass when two separate galaxies merged into one. If this is indeed the case, odds are that one of the galaxies involved was a dwarf galaxy, she explained to BBC News.
Alternatively, it may be a rare example of an intermediate-sized black hole that could eventually become supermassive. Intermediate black holes are between 100 and one million times the mass of our sun, and scientists have yet to confirm that such a black hole exists, the AP noted.
“Maybe this small sphere of stars is actually appropriate for an intermediate-mass black hole,” the Colorado professor told BBC News. “There are very few of these known—they are very rare and hard to find—but they’re interesting because we think they may be an evolutionary stopover in the process of building supermassive black holes.”
If it turns out not to be an intermediate black hole, then “the answer may lie in the galaxy merger itself,” Comerford continued. “When two galaxies merge, there are very strong gravitational and tidal forces that can strip away the stars from around the black hole.” A paper detailing her work was published in a recent edition of The Astrophysical Journal.
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Feature Image: University of Colorado
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