This class of sources emit in the whole electromagnetic spectrum, a rather uncommon phenomenon which requires extreme physical conditions. Hence, a study of such sources tells us about the behaviour of matter in an extreme gravitational field where it is difficult for light to escape from the vicinity of the black hole.
Astronomers at Aryabhatta Research Institute of Observational Sciences, an autonomous institute of the Department of Science and Technology, Government of India, have been monitoring one such black hole system named 'OJ 287' since 2015. This source shows a repeated optical brightness enhancement almost every 12 . . .
November 29, 2021