Messier 66 orM66, also known asNGC 3627, is anintermediate spiral galaxy in the southern,equatorial half ofLeo. It was discovered by French astronomerCharles Messier[8] on 1 March 1780, who described it as "very long and very faint".[9] This galaxy is a member of a small group of galaxies that includesM65 andNGC 3628, known as theLeo Triplet or the M66 Group.[10] M65 and M66 are a common object foramateur astronomic observation, being separated by only20′.[9]
M66 has amorphological classification of SABb,[5] indicating a spiral shape with a weakbar feature and loosely woundarms. Theisophotal axis ratio is 0.32, indicating that it is being viewed at an angle.[5] M66 is receding from us with a heliocentricradial velocity of696.3±12.7 km/s.[3] It lies 31[4] millionlight-years away and is about 95 thousand light-years across[11] with strikingdust lanes and bright star clusters along sweeping spiral arms.
Gravitational interaction from its past encounter with neighboring NGC 3628 has resulted in an extremely high central mass concentration; a highmolecular toatomic mass ratio; and a resolved non-rotating clump ofH I material apparently removed from one of thespiral arms. The latter feature shows up visually as an extremely prominent and unusual spiral arm and dust lane structures as originally noted in theAtlas of Peculiar Galaxies.[12]
^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.
^abde Vaucouleurs, G.; et al. (1991),Third reference catalogue of bright galaxies, 9, New York:Springer-Verlag.
^"SN1973R".Transient Name Server.IAU. Retrieved3 December 2024.
^Evans, R. O.; McNaught, R. H. (1989). "Supernova 1989B in NGC 3627".International Astronomical Union Circular (4726): 1.Bibcode:1989IAUC.4726....1E.
^"SN1989B".Transient Name Server.IAU. Retrieved3 December 2024.
^Treffers, R. R.; Peng, C. Y.; Filippenko, A. V.; Richmond, M. W.; Barth, A. J.; Gilbert, A. M. (1997). "Supernova 1997bs in NGC 3627".International Astronomical Union Circular (6627): 1.Bibcode:1997IAUC.6627....1T.
^"SN1997bs".Transient Name Server.IAU. Retrieved3 December 2024.
^Van Dyk, Schuyler D.; Peng, Chien Y.; King, Jennifer Y.; Filippenko, Alexei V.; Richards, R. R.; Li, Weidong; Richmond, Michael W. (2000). "SN 1997bs in M66: Another Extragalactic η Carinae Analog?".Publications of the Astronomical Society of the Pacific.112 (778):1532–1541.arXiv:astro-ph/0009027.Bibcode:2000PASP..112.1532V.doi:10.1086/317727.
^Reguitti, A.; Pastorello, A.; Valerin, G. (2025). "The fate of the progenitors of Luminous Red Novae: Infrared detection of LRNe years after the outburst".arXiv:2504.14592 [astro-ph.SR].
^Monard, L. A. G. (2009). "Supernova 2009hd in M66".Central Bureau Electronic Telegrams (1867): 1.Bibcode:2009CBET.1867....1M.
^"SN2009hd".Transient Name Server.IAU. Retrieved3 December 2024.
^Sutaria, Firoza; Ray, Alak (June 2016), "No X-ray detection of SN2016cok by Swift XRT",The Astronomer's Telegram,9189: 1,Bibcode:2016ATel.9189....1S.
^"SN2016cok".Transient Name Server.IAU. Retrieved2 December 2024.
