Messier 84
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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 1781Template:Efn in a systematic search for "nebulous objects" in the night sky.<ref name="jonesbook1991"/> 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.<ref name="Finoguenovetal2002"/>
This galaxy has morphological classification E1, denoting it has flattening of about 10%. The extinction-corrected total luminosity in the visual band is about Template:Val. 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.<ref name=Napolitano2011/>
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 Template:Solar mass<ref name="Bower et al. 1998"/> supermassive black hole. It also has a few young stars and star clusters, indicating star formation at a very low rate.<ref name="ford2012"/> The number of globular clusters is Template:Val, which is much lower than expected for an elliptical galaxy.<ref name=Gómez2004/>
Viewed from Earth its half-light radius, relative angular size of its 50% peak of lit zone of the sky, is Template:Val, thus just over an arcminute.
Supernovae
Three supernovae have been observed in M84:
- SN 1957B ([[type_Ia_supernova|TypeTemplate:NbspIa]], mag. 12.5) was discovered by Howard S. Gates on 28 April 1957, and independently by Dr. Giuliano Romano on 18 May 1957.<ref name="Götz1958"/><ref name="iauc1600" /><ref>Template:Cite web</ref>
- SN 1980I (Type Ia, mag. 14) was discovered by M. Rosker on 13 June 1980.<ref name="iauc3492" /><ref>Template:Cite web</ref> Historically, this supernova has been catalogued as belonging to M84, but it may have been in either neighboring galaxy NGC 4387 or M86.<ref name="Smith1981"/>
- SN 1991bg (Type Ia-pec, mag. 14) was discovered by Reiki Kushida on 3 December 1991.<ref name="Kosaietal1991"/><ref>Template:Cite web</ref> This supernova has been studied extensively as a peculiar and underluminous Type Ia, and is now used as a template, with similar events being classified as Type Ia-91bg-like.<ref>Template:Cite journal</ref>
This high rate of supernovae is rare for elliptical galaxies, which may indicate there is a population of stars of intermediate age in M84.<ref name=Gómez2004/>
See also
References and footnotes
Template:Reflist Template:Notelist
External links
Template:Portal bar Template:Virgo Template:Messier objects Template:Ngc45 Template:Sky