NGC 3921 is the remnant of agalaxy merger. The two progenitor galaxies are thought to have beendisk galaxies that collided about 700 million years ago.[8] The image shows noticeablestar formation and structures like loops, indicative of galaxies interacting.[8] Because of this, NGC 3921 was included inHalton Arp'sAtlas of Peculiar Galaxies under the designationArp 224.[4]
Being astarburst galaxy, NGC 3921 has important features. One of them is anultraluminous X-ray source, designatedX-2, with an X-ray luminosity of8×1039erg/s.[9] Additionally, two candidateglobular clusters have been detected within NGC 3921.[5] They are both fairly young, and about half as massive asOmega Centauri, demonstrating that mergers of gas-rich galaxies can also create more metal-rich globular clusters.[5]
^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.
^Jonker, P. G.; Heida, M.; Torres, M. A. P.; Miller-Jones, J. C. A.; Fabian, A. C.; Ratti, E. M.; Miniutti, G.; Walton, D. J.; Roberts, T. P. (2012). "The Nature of the Bright Ulx X-2 in Ngc 3921: Achandraposition Andhstcandidate Counterpart".The Astrophysical Journal.758 (1): 28.arXiv:1208.4502.Bibcode:2012ApJ...758...28J.doi:10.1088/0004-637X/758/1/28.S2CID59330131.
Media related toNGC 3921 at Wikimedia Commons