Black Eye Galaxy

Black Eye Galaxy^[1]

The Black Eye Galaxy (M64)
Observation data Epoch J2000
Constellation	Coma Berenices[2]
Right ascension	12h 56m 43.7s[3]
Declination	+21° 40′ 58″[3]
Apparent dimension (V)	10.71 × 5.128 moa[4]
Apparent magnitude (V)	9.36[3]
Characteristics
Type	(R)SA(rs)ab, HIISy2
Astrometry
Helio Radial velocity	408 ± 4[3]km/s
Redshift	0.001361 ± 0.000013[3]
Galactocentric Velocity	400 ± 4 km/s
Distance	24 ± 2 Mly (7.4 ± 0.61 Mpc)
Other designations
M64,[3] NGC 4826,[3] UGC 8062,[3] PGC 44182,[3] Evil Eye Galaxy[4]
Database references
SIMBAD	Search M64 data
See also: Galaxy, List of galaxies

The Black Eye Galaxy (also called Sleeping Beauty Galaxy; designated Messier 64, M64, or NGC 4826) was discovered by Edward Pigott in March 1779, and independently by Johann Elert Bode in April of the same year, as well as by Charles Messier in 1780. It has a spectacular dark band of absorbing dust in front of the galaxy's bright nucleus, giving rise to its nicknames of the "Black Eye" or "Evil Eye" galaxy. M64 is well known among amateur astronomers because of its appearance in small telescopes. It is a spiral galaxy in the Coma Berenices constellation.

General information

At first glance, M64 seems to be a fairly normal spiral galaxy. As in the majority of galaxies, all of the stars in M64 are orbiting in the same direction, clockwise as seen in the Hubble image.

However, recent detailed studies have led to the remarkable discovery that the interstellar gas in the outer regions of M64 rotates in the opposite direction from the gas and stars in the inner regions. The inner region has a radius of only approximately 3,000 light-years, while the outer section extends another 40,000 light-years. This pattern is believed to trigger the creation of many new stars around the boundary separating the two regions.

A collision of two galaxies has left a merged star system with an unusual appearance as well as bizarre internal motions. Astronomers believe that the oppositely rotating gas arose when M64 absorbed a satellite galaxy that collided with it, perhaps more than one billion years ago. Active formation of new stars is occurring in the shear region where the oppositely rotating gases collide, are compressed, and contract.

Particularly noticeable in the image are hot, blue young stars that have just formed, along with pink clouds of glowing hydrogen gas that fluoresce when exposed to ultraviolet light from newly formed stars. It is approximately 17 million light years from earth. The small galaxy that impinged on its neighbour has now been almost completely destroyed, its stars either merged with the main galaxy or scattered into space, but signs of the collision persist in the backward motion of gas at the outer edge of M64.

References

1. ^ J. L. Tonry, A. Dressler, J. P. Blakeslee, E. A. Ajhar, A. B. Fletcher, G. A. Luppino, M. R. Metzger, C. B. Moore (2001). "The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances". Astrophysical Journal 546 (2): 681–693. arXiv:astro-ph/0011223. Bibcode 2001ApJ...546..681T. doi:10.1086/318301. 
2. ^ R. W. Sinnott, ed (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation/Cambridge University Press. ISBN 0-933-34651-4. 
3. ^ ^{a b c d e f g h i} "NASA/IPAC Extragalactic Database". Results for NGC 4826. http://nedwww.ipac.caltech.edu/. Retrieved 2006-11-06. 
4. ^ ^{a b} "Object query : M64". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=M64. Retrieved 2008-07-09. 

External links

• Messier 64, SEDS Messier pages
• Hubblesite description and high resolution images
• ESA/Hubble images of M64
• APOD for August 2, 2007
• The Black Eye Galaxy on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
• a real photo by Pete Albrecht

Coordinates: 12^h 56^m 43.7^s, +21° 40′ 58″