Evidence of Past Explosions at the Center of the Milky Way ―Is It Another Super Massive Star Cluster ?―
April 9, 2018
A research team centered around Shiho Tsujimoto at Keio University’s Graduate School of Science and Technology (1st year doctoral student) and Professor Tomoharu Oka of the Department of Physics at the Faculty of Science and Technology discovered a peculiar molecular cloud with an unusually broad velocity width at the center of the Milky Way about 30,000 light-years away from the Solar System. This peculiar molecular cloud is roughly 50 light-years in size, containing at least 5 expanding spherical shell structures. It is thought that these are the result of a massive explosion that occurred here approximately 100,000 years ago. The energy released from the explosion is the equivalent of about 10 supernova explosions, and it is speculated that a super massive star cluster with a mass of several hundred thousand solar masses is embedded inside. Within these super massive star clusters located at the center of the Milky Way, it is thought that intermediate-mass black holes are formed through the repeated merging of stars and black holes. The super massive star cluster that was discovered this time is thought to be a “cradle” candidate for these intermediate-mass black holes and it is the second example to be found in the Milky Way following the earlier discovery of a star cluster by the same team in 2012.
The findings of this research were published in the March 28 issue of the American scientific journal The Astrophysical Journal.