M60 is an elliptical galaxy of type E1+1⁄2 (E1.5), although some sources class it as S0 – alenticular galaxy. An E2 class indicates aflattening of 20%, which has a nearly round appearance. Theisophotes of the galaxy are boxy in shape, rather than simple ellipses. Themass-to-light ratio is a near constant 9.5 in the V (visual) band of theUBV system.[6] The galaxy has aneffective radius of128″ (translating, at its distance, to about 10 kpc[6]), with an estimated mass of ~1012M☉ within a threefold volume, of which nearly half isdark matter.[10] The mass estimated fromX-ray emission is(1.0±0.1)×1012M☉ within 5 effective radii.[11]
At the center of M60 is asupermassive black hole (SMBH) of4.5±1.0 billion solar masses, one of thelargest ever found.[12] It is currentlyinactive. X-ray emission from the galaxy shows a cavity created byjets emitted by the hole during past active periods, which correspond to weak radio lobes. Thepower needed to generate these features is in the range(6–7)×1041 erg·s−1 (ergs per second).[13]
M60 is the third-brightest giant elliptical galaxy of theVirgo cluster of galaxies, and is the dominant member of a subcluster of four galaxies, the M60 group, which is the closest-known isolated compact group of galaxies.[16] It has several satellite galaxies, one of them being theultracompact dwarf galaxyM60-UCD1, discovered in 2013.[17] The motion of M60 through theintercluster medium is resulting inram-pressure stripping of gas from the galaxy's outer halo, beyond a radius of 12 kpc.[11]
NGC 4647 appears approximately 2.5′ from Messier 60; the optical disks of the two galaxies overlap. Although this overlap suggests that the galaxies are interacting, photographic images of the two galaxies do not reveal any evidence forgravitational interactions between the two galaxies as would be suggested if the two galaxies were physically close to each other.[18] This suggests that the galaxies are at different distances and are only weakly interacting if at all.[18] However, studies with the Hubble Space Telescope show indications that a tidal interaction may have just begun.[8]
Messier 60 was the fastest-moving galaxy included inEdwin Hubble's landmark 1929 paper concerning the relationship between recession speed and distance.[19] He used a value of 1090 km/s for the recession speed, 1.8% less than the more recent value of about 1110 km/s (based on a redshift of 0.003726). But he estimated the distance of this galaxy as well as of the three nebulas of theVirgo Cluster which he included (Messier 85,49, and87), to be only two million parsecs, rather than the accepted value today of around 16 million parsecs. These errors in distance led him to propose aHubble constant of 500 km/s/Mpc, whereas the present estimate is around 70 km/s/Mpc.
^abSkrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W.; Chester, Thomas; Elias, Jonathan H.; Huchra, John P.; Liebert, James W.; Lonsdale, Carol J.; Monet, David G.; Price, Stephan; Seitzer, Patrick; Jarrett, Thomas H.; Kirkpatrick, J. Davy; Gizis, John E.; Howard, Elizabeth V.; Evans, Tracey E.; Fowler, John W.; Fullmer, Linda; Hurt, Robert L.; Light, Robert M.; Kopan, Eugene L.; Marsh, Kenneth A.; McCallon, Howard L.; Tam, Robert; Van Dyk, Schuyler D.; Wheelock, Sherry L. (1 February 2006)."The Two Micron All Sky Survey (2MASS)".The Astronomical Journal.131 (2):1163–1183.Bibcode:2006AJ....131.1163S.doi:10.1086/498708.ISSN0004-6256.S2CID18913331.
^"Messier 60".SEDS Messier Catalog. Retrieved29 April 2022.
^abcDe Bruyne, V.; et al. (January 2001), "Toward an Alternative Way of Looking at Elliptical Galaxies: Case Studies for NGC 4649 and NGC 7097",The Astrophysical Journal,546 (2):903–915,Bibcode:2001ApJ...546..903D,doi:10.1086/318275,hdl:11577/1363890.
Frommert, Hartmut; Kronberg, Christine (August 30, 2007),"Messier 60",SEDS Messier pages, Students for the Exploration and Development of Space (SEDS), retrieved2018-12-12.
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