Messier 84 or M84, also known as NGC 4374, is a giant elliptical or lenticular galaxy in the constellation Virgo. Charles Messier discovered the object in 1781[a] in a systematic search for "nebulous objects" in the night sky.[7] It is the 84th object in the Messier Catalogue and in the heavily populated core of the Virgo Cluster of galaxies, part of the local supercluster.[8]
This galaxy has morphological classification E1, denoting it has flattening of about 10%. The extinction-corrected total luminosity in the visual band is about 7.64×1010 L☉. The central mass-to-light ratio is 6.5, which, to a limit, steadily increases away from the core. The visible galaxy is surrounded by a massive dark matter halo.[5]
Radio observations and Hubble Space Telescope images of M84 have revealed two jets of matter shooting out from its center as well as a disk of rapidly rotating gas and stars indicating the presence of a 1.5 ×109 M☉[9] supermassive black hole. It also has a few young stars and star clusters, indicating star formation at a very low rate.[10] The number of globular clusters is 1,775±150, which is much lower than expected for an elliptical galaxy.[11]
Viewed from Earth its half-light radius, relative angular size of its 50% peak of lit zone of the sky, is 72.5″, thus just over an arcminute.
Two supernovae have been observed in M84: SN 1957[12] and SN 1991bg.[13] Seen between these dates, it may have bore a third, SN 1980I – which may have been in either neighboring galaxy NGC 4387 or M86.[14] This high rate of supernovae is rare for elliptical galaxies, which may indicate there is a population of stars of intermediate age in M84.[11]
