Messier 49

Messier 49 (also known as M 49 or NGC 4472) is an elliptical galaxy located about 56 million light-years away in the equatorial constellation of Virgo. This galaxy was discovered by French astronomer Charles Messier on February 16, 1777.

Messier 49
Image taken by Hubble Space Telescope, September 14, 2009
Observation data
Epoch J2000
Constellation Virgo
Right ascension  12h 29m 46.7s[1]
Declination +08° 00′ 02″[1]
Apparent dimension (V) 10.2 × 8.3 moa[1]
Apparent magnitude (V)9.4[1]
Characteristics
TypeE2,[1] LINER[1]
Astrometry
Heliocentric radial velocity 997 ± 7[1] km/s
Redshift 0.003326 ± 0.000022[1]
Galactocentric velocity 929 ± 7[1] km/s
Distance 55.9 ± 2.3 Mly (17.14 ± 0.71 Mpc)
Other designations
NGC 4472,[1] UGC 7629,[1] PGC 41220,[1] Arp 134[1]
Database references
SIMBAD Search M49 data
    See also: Galaxy, List of galaxies

    As an elliptical galaxy, Messier 49 has the physical form of a radio galaxy, but it only has the radio emission of a normal galaxy. From the detected radio emission, the core region has roughly 1053 erg (1046 J or 1022 YJ) of synchrotron energy.[2] The nucleus of this galaxy is emitting X-rays, suggesting the likely presence of a supermassive black hole with an estimated mass of 5.65 × 108 solar masses, or 565 million times the mass of the Sun.[3] X-ray emissions shows a structure to the north of Messier 49 that resembles a bow shock. To the southwest of the core, the luminous outline of the galaxy can be traced out to a distance of 260 kpc.[4] The only supernova event observed within this galaxy is SN 1969Q,[5] discovered in June 1969.[6]

    This galaxy has a large collection of globular clusters, estimated at about 5,900. By contrast, this count is far more than the roughly 200 orbiting the Milky Way, but is 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.[7] Between 2000 and 2009, strong evidence for a stellar mass black hole was discovered in an M 49 cluster. A second candidate was announced in 2011.[8]

    Messier 49 was the first member of the Virgo Cluster of galaxies to be discovered.[9] It is the most luminous member of that cluster and more luminous than any galaxy closer to the Earth. This galaxy forms part of the smaller Virgo B subcluster located 4.5° away from the dynamic center of the Virgo Cluster, centered on Messier 87.[7][10] Messier 49 is gravitationally interacting with the dwarf irregular galaxy UGC 7636.[4] The dwarf shows a trail of debris spanning roughly 1 × 5 arcminutes, which corresponds to a physical dimension of 6 × 30 kpc.[11]

    References
    1. "NASA/IPAC Extragalactic Database", Results for NGC 4472, retrieved September 26, 2006.
    2. Ekers, R. D.; Kotanyi, C. G. (June 1978), "NGC 4472 – A very weak radio galaxy", Astronomy and Astrophysics, 67 (1): 47–50, Bibcode:1978A&A....67...47E.
    3. Loewenstein, Michael; et al. (July 2001), "Chandra Limits on X-Ray Emission Associated with the Supermassive Black Holes in Three Giant Elliptical Galaxies" (PDF), The Astrophysical Journal, 555 (1): L21–L24, arXiv:astro-ph/0106326, Bibcode:2001ApJ...555L..21L, doi:10.1086/323157.
    4. Irwin, Jimmy A.; Sarazin, Craig L. (November 1996), "X-Ray Evidence for the Interaction of the Giant Elliptical Galaxy NGC 4472 with Its Virgo Cluster Environment", The Astrophysical Journal, 471 (2): 683, Bibcode:1996ApJ...471..683I, doi:10.1086/177998.
    5. "NASA/IPAC Extragalactic Database", Results for supernova search near name "NGC 4472", retrieved February 12, 2007.
    6. Barbon, R.; et al. (1984), "A revised supernova catalogue", Astronomy & Astrophysics Supplement Series, 58: 735–750, Bibcode:1984A&AS...58..735B.
    7. Cohen, Judith G.; Blakeslee, J. P.; Côté, P. (August 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.
    8. Maccarone, Thomas J.; et al. (January 2011), "A new globular cluster black hole in NGC 4472", Monthly Notices of the Royal Astronomical Society, 410 (3): 1655–1659, arXiv:1008.2896, Bibcode:2011MNRAS.410.1655M, doi:10.1111/j.1365-2966.2010.17547.x.
    9. Thompson, Robert Bruce; Thompson, Barbara Fritchman (2007), Illustrated guide to astronomical wonders, DIY science, O'Reilly Media, Inc., p. 492, ISBN 978-0-596-52685-6.
    10. Sandage, A.; Bedke, J. (1994), Carnegie Atlas of Galaxies, Carnegie Institution of Washington, ISBN 978-0-87279-667-6.
    11. McNamara, Brian R.; et al. (September 1994), "A violent interaction between the dwarf galaxy UGC 7636 and the giant elliptical galaxy NGC 4472", The Astronomical Journal, 108 (3): 844–850, Bibcode:1994AJ....108..844M, doi:10.1086/117116.


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