Sagittarius B2 (Sgr B2) is a giant molecular cloud of gas and dust that is located about 120 parsecs (390 ly) from the center of the Milky Way.
[12] Because the average temperature and pressure in Sgr B2 are low, chemistry based on the direct interaction of atoms is exceedingly slow.
However, the Sgr B2 complex contains cold dust grains consisting of a silicon core surrounded by a mantle of water ice and various carbon compounds.
[13] The European Space Agency's gamma-ray observatory INTEGRAL has observed gamma rays interacting with Sgr B2, causing X-ray emission from the molecular cloud.
This energy was emitted about 350 years prior by the supermassive black hole (SMBH) at the galaxy's core, Sagittarius A*.
The total luminosity from this outburst is an estimated million times stronger than the current output from Sagittarius A*.