Messier 105

Messier 105 or M105, also known as NGC 3379, is an elliptical galaxy 36.6<ref name=Tully2016/> million light-years away in the equatorial constellation of Leo. It is the biggest elliptical galaxy in the Messier catalogue that is not in the Virgo cluster.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It was discovered by Pierre Méchain in 1781, just a few days after he discovered the nearby galaxies Messier 95 and Messier 96.Template:Efn<ref name="jonesbook1991"/> This galaxy is one of a few not object-verified by Messier so omitted in the editions of his Catalogue of his era. It was appended when Helen S. Hogg found a letter by Méchain locating and describing this object which matched those aspects under its first-published name, NGC 3379.<ref name="jonesbook1991" />

It has a morphological classification of E1,<ref name=Tian2016/> indicating a standard elliptical galaxy with a flattening of 10%. The major axis is aligned along a position angle of 71°. Isophotes of the galaxy are near perfect ellipses, twisting no more than 5° out of alignment, with changes in ellipticity of no more than 0.06. There is no fine structure apparent in the isophotes, such as ripples.<ref name=Statler1994/> Observation of giant stars in the halo indicate there are two general populations: a dominant metal-rich subpopulation and a weaker metal-poor group.<ref name=Lee2016/>

Messier 105 is known to have a supermassive black hole at its core whose mass is estimated to be between Template:Val and Template:Val.<ref name="shapiro2006"/> The galaxy has a weak active galactic nucleus of the LINER type with a spectral class of L2/T2, meaning no broad Hα line and intermediate emission line ratios between a LINER and a H II region.<ref name=Eracleous2010/> The galaxy also contains a few young stars and stellar clusters, suggesting some elliptical galaxies still form new stars, but very slowly.<ref name="ford2012"/>

This galaxy, along with its companion the barred lenticular galaxy NGC 3384, is surrounded by an enormous ring of neutral hydrogen with a radius of Template:Convert and a mass of Template:Val where star formation has been detected.<ref name="thilker2009"/> Messier 105 is one of several galaxies within the M96 Group (also known as the Leo I Group), a group of galaxies in the constellation Leo, the other Messier objects of which are M95 and M96.<ref name="nbg"/><ref name="fouqueetal1992"/><ref name="garcia1993"/><ref name="giuricinetal2002"/> It is one of the richest group of galaxies in the Local Volume, and unlike the Local Group, it is dominated by not one but several galaxies.<ref name=Karachentsev/>

See also

• List of Messier objects

External links

• Template:WikiSky
• "StarDate: M105 Fact Sheet"
• SEDS: Elliptical Galaxy M105
• ESA/Hubble image of M105 Template:Webarchive
• {{#invoke:citation/CS1|citation

|CitationClass=web }}