Messier 49 (also known as NGC 4472) is an elliptical galaxy about 49 million light-years away in the constellation of Virgo. This galaxy was discovered by French astronomer Charles Messier in 1771. Messier 49 is 4.1° west-southwest of the star Epsilon Virginis.
Messier 49 was the first member of the Virgo Cluster of galaxies to be discovered. It is the most luminous member of that cluster and is brighter than any galaxy closer to the Earth. This galaxy is part of the smaller Virgo B subcluster 4.5° away from the dynamic center of the Virgo Cluster, which is centered on Messier 87. Messier 49 is gravitationally interacting with the dwarf irregular galaxy UGC 7636.
Messier 49 has the radio emission of a normal galaxy. However, the core of the galaxy is emitting X-rays, which suggests the presence of a supermassive black hole of 5.65 × 108 solar masses, or 565 million times the mass of the Sun. To the southwest of the core, the luminous outline of the galaxy can be traced out to a distance of 260 thousand parsecs. The only supernova event observed within this galaxy is SN 1969Q, discovered in June 1969.
This galaxy has a large collection of globular clusters, estimated at about 5,900. However, this count is far exceeded by the 13,450 globular clusters orbiting the supergiant elliptical galaxy Messier 87. On average, the globular clusters of M 49 are about 10 billion years old. Between 2000–2009, strong evidence for a stellar mass black hole was discovered in an M 49 cluster. A second candidate was announced in 2011.
References[change | change source]
- Thompson, Robert Bruce; Thompson, Barbara Fritchman (2007), Illustrated guide to astronomical wonders, DIY science, O'Reilly Media, p. 492, ISBN 0-596-52685-7.
- Cohen, Judith G.; Blakeslee, J. P.; Côté, P. (2003), "The ages and abundances of a sample of globular clusters in M49 (NGC 4472)", The Astrophysical Journal, 592 (2): 866–883, arXiv:astro-ph/0304333, Bibcode:2003ApJ...592..866C, doi:10.1086/375865.
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- Irwin, Jimmy A.; Sarazin, Craig L. (1996), "X-ray evidence for the interaction of the giant elliptical galaxy NGC 4472 with its Virgo Cluster environment", Astrophysical Journal, 471: 683, Bibcode:1996ApJ...471..683I, doi:10.1086/177998.
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- Loewenstein, Michael; et al. (2001), "Chandra limits on X-Ray emission associated with the supermassive black holes in three giant elliptical galaxies", The Astrophysical Journal, 555 (1): L21–L24, arXiv:astro-ph/0106326, Bibcode:2001ApJ...555L..21L, doi:10.1086/323157.
- "NASA/IPAC Extragalactic Database", Results for supernova search near name "NGC 4472", retrieved 2007-02-12.
- Barbon, R.; et al. (1984), "A revised supernova catalogue", Astronomy & Astrophysics Supplement Series, 58: 735–750, Bibcode:1984A&AS...58..735B.
- Stellar black holes, formed by the collapse of a star, are much smaller than the black holes at the centre of galaxies.
- Maccarone, Thomas J.; et al. (2011), "A new globular cluster black hole in NGC 4472", Monthly Notices of the Royal Astronomical Society, 410 (3): 1655–1659, Bibcode:2011MNRAS.410.1655M, doi:10.1111/j.1365-2966.2010.17547.x.