Astronomers from the National Astronomical Observatory of Japan have detected signs of an invisible black hole around the center of the Milky Way using the Nobeyama 45-m Radio Telescope, marking what may be the second largest black hole in our universe. With a mass 100,000 times that of our sun, the team of researchers believes that this finding may help us advance our understanding of the supermassive black holes that exists at the centers of galaxies.
The finding stemmed from the gas cloud CO-0.40-0.22, located just 200 light years from the center of the Milky Way, which possesses gases that contain an unusually wide range of speeds. After noticing this oddity, the team observed the cloud and obtained 21 emission lines from 18 molecules and found that the cloud has an elliptical shape that houses two main components: a low-density area with a wide range of gas speeds and a high-density area with a small range of gas speeds.
The team then performed a simulation of the gas clouds and found that this strange speed gradient could only be explained by the presence of a gravity source, such as a black hole, with 100,000 times the mass of the sun.
"Considering the fact that no compact objects are seen in X-ray or infrared observations, as far as we know, the best candidate for the compact massive object is a black hole," Tomoharu Oka, lead author of the paper, said in a press release.
Scientists have so far only been able to detect stellar-mass black holes and supermassive black holes, meaning that if the results are accurate, this will mark the first detection of an intermediate black hole. The team suggests that there are many other gas clouds with similar speed distributions as CO-0.40-0.22, meaning that there may be many more of these intermediate black holes that have yet to be discovered.
The findings were published in the Jan. 1 issue of The Astrophysical Journal Letters.
