This showed that about 200 million solar masses of material resides inside the nuclear disk. The astronomers quickly realized that this enormous mass within the central region cannot be caused by normal stars, as it would then be much more luminous. Instead they conclude that the most conservative explanation for the dark, central mass concentration observed in Centaurus A is indeed a supermassive black hole. This discovery confirms the previous suspicion that the active nucleus of Centaurus A is powered by a supermassive black hole. It is the first time infrared spectroscopy has been used to weigh a black hole.
North is up and East is left.
Three spectrograph slits were used, but only one of these is shown here.