Astronomers may have found a massive black hole lying near the center of the Milky Way hidden by a cloud of molecular gas.
Intermediate-Mass Black Holes
The estimated mass of the potential black hole is about 100,000 times than that of the sun. The object may belong to a long-hypothesized but not yet officially identified type of black holes known as intermediate-mass black holes, or IMBHs.
Intermediate-mass black holes are considered to be the missing link that can help explain the formation of supermassive black holes but to date, no direct evidence of IMBH has yet been found.
"We think some of those black holes are the seeds from which the much larger supermassive black holes grow to at least a million times more massive," said Brooke Simmons, from the University of California at San Diego, who is not part of the study.
"That growth should happen in part by mergers with other black holes and in part by accretion of material from the part of the galaxy that surrounds the black hole."
New Candidate For IMBH
In the study published in the journal Nature Astronomy, Tomoharu Oka, from Keio University in Japan, and colleagues reported a new candidate for IMBH after using a powerful telescope in Chile's Atacama desert toward a gas cloud 200 light years away from the center of the Milky Way. The researchers wanted to understand the peculiar movements of the cloud's gases.
The cloud exhibits some unusual properties that were not observed in similar structures. Gases in this cloud, which include carbon monoxide and hydrogen cyanide, were found to move at different speeds.
Data gathered using the Atacama Large Millimeter Array, or ALMA telescope, revealed that the molecules in the elliptical cloud, which spans 150 trillion kilometers wide, were being pulled around by immense gravitational forces.
Computer models suggest that this is most likely caused by an invisible compact object: an inactive IMBH that does not currently accrete matter.
If the entity is confirmed to be a black hole, it will be the second largest black hole discovered in the Milky Way, the first being the supermassive black hole Sagittarius A*, which lies right at the very center of our galaxy.
"Based on the careful analysis of gas kinematics, we concluded that a compact object with a mass of about 105M⊙ is lurking in this cloud," the researchers wrote in their study, which was published online on Sept. 4.
"Numerical simulations around a point-like massive object reproduce the kinematics of dense molecular gas well, which suggests that CO-0.40-0.22* is one of the most promising candidates for an intermediate-mass black hole."