Messier 84

Messier 84 (also known as "NGC 4374") is a lenticular galaxy in the constellation of Virgo. M84 is in the heavily populated inner core of the Virgo Cluster of galaxies.
Radio observations and Hubble Space Telescope images of M84 have revealed two jets of matter shooting out from the galaxy's centre, as well as a disk of rapidly rotating gas and stars. This suggests there is a supermassive black hole at the centre of the galaxy. Its mass is 1.5 M☉, that is gravitation amounting to 15 billion solar masses.
History.
Charles Messier discovered Messier 84 in 1781 when he searched for "nebulous objects" in the night sky. The object is the 84th in the Messier Catalogue.
Supernovae.
Two supernovae have been observed in M84: SN 1957
and SN 1991bg.
Possibly, a third, SN 1980I is part of M84 or, alternatively, one of its neighboring galaxies, NGC 4387 and M86.