Free Astronomy Magazine May-June 2019

51 MAY-JUNE 2019 SPACE CHRONICLES the Galaxy 25,000 light-years away from Earth in the constellation Sagittarius. They used ALMA (Ata- cama Large Millimeter/submillime- ter Array) to perform high resolu- tion observations of the cloud and found that it is swirling around an invisible massive object. Takekawa explains, “Detailed kine- matic analyses revealed that an enormous mass, 30,000 times that of the Sun, was concentrated in a region much smaller than our Solar System. This and the lack of any observed object at that location strongly suggests an intermediate- mass black hole. By analyzing other anomalous clouds, we hope to ex- pose other quiet black holes.” Tomoharu Oka, a professor at Keio University and coleader of the team, adds, “It is significant that this inter- mediate mass black hole was found only 20 light-years from the super- massive black hole at the Galactic center. In the future, it will fall into the supermassive black hole; much like gas is currently falling into it. This supports the merger model of black hole growth.” A rtist’s impression of a gas cloud swirling around a black hole. [NAOJ] !