Evolution and Activities of the Galactic Nucleus Sgr A*
speaker: Yuhei Iwata
Abstract:
The nucleus of our Galaxy, Sgr A, is one of the most convincing candidates for a supermassive black hole (SMBH). It shows short timescale variations of a few tens of minutes, which are suggested to be related to orbital motions in the vicinity of the SMBH. However, the truth and cause of these variations have remained controversial. Also, as for the formation process of SMBHs, a merger scenario between intermediate-mass black holes (IMBHs) has been proposed, but there are very few promising candidates for IMBHs, and it is insufficient to support this scenario. I have been researching time variations of Sgr A in the mm/sub-mm band and peculiar molecular clouds in the Galactic center having broad velocity widths to which IMBHs may be associated. I will introduce the short-timescale variability of Sgr A* obtained with ALMA and the latest observational results of the high-velocity compact clouds.