Messier 99

Messier 99
A near-infrared image of M99. Credit: 2MASS/NASA.
Observation data (J2000 epoch)
Constellation	Coma Berenices[1]
Right ascension	12h 18m 49.6s[2]
Declination	+14° 24′ 59″[2]
Redshift	0.008029[2]
Helio radial velocity	2407 ± 3 km/s[2]
Distance	50.2 ± 5.5 Mly (15.4 ± 1.7 Mpc)[3]
Type	SA(s)c[2]
Apparent dimensions (V)	5′.4 × 4′.7
Apparent magnitude (V)	10.4[2]
Other designations
NGC 4254,[2] UGC 7345,[2] PGC 39578,[2] Coma Pinwheel Galaxy,[4] Virgo Cluster Pinwheel[4]
See also: Galaxy, List of galaxies

Messier 99 (also known as M99 or NGC 4254) is an unbarred spiral galaxy approximately 50 million light-years away^[3] in the constellation Coma Berenices.

The galaxy has a normal looking arm and an extended arm that is less tightly wound. A bridge of neutral hydrogen gas links NGC 4254 with VIRGOHI21. The gravity from the possible dark galaxy VIRGOHI21 may have distorted M99 and drawn out the gas bridge, as the two galaxy-sized objects have a close encounter, before they go their separate ways. It is expected that the drawn out arm will relax to match the normal arm once the encounter is over. Three supernovae have been observed in this galaxy.

Image of Messier 99 with amateur telescope

History

Messier 99 was discovered by Pierre Méchain on March 17, 1781 along . The discovery was then reported to Charles Messier, who included the object in the Messier Catalogue, which was the first astronomical catalogue of star clusters, nebulae, and galaxies.^[5]

Messier 99 was one of the first galaxies in which a spiral pattern was first seen. The spiral pattern was first identified by Lord Rosse in the spring of 1846.^[5]

See also

• Messier 83 - a similar face-on spiral galaxy
• Pinwheel Galaxy - a similar face-on spiral galaxy

References

1. ^ 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. 
2. ^ ^{a b c d e f g h i} "NASA/IPAC Extragalactic Database". Results for NGC 4254. http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Messier+99&img_stamp=yes. Retrieved 2006-11-25. 
3. ^ ^{a b} "Distance Results for MESSIER 099". NASA/IPAC Extragalactic Database. http://nedwww.ipac.caltech.edu/cgi-bin/nDistance?name=MESSIER+099. Retrieved 2010-04-30. 
4. ^ ^{a b} "SIMBAD Astronomical Database". Results for NGC 4254. http://simbad.u-strasbg.fr/Simbad. Retrieved 2006-11-25. 
5. ^ ^{a b} K. G. Jones (1991). Messier's Nebulae and Star Clusters (2nd ed.). Cambridge University Press. ISBN 0-521-37079-5. 

External links

• SEDS: Spiral Galaxy M99
• UniverseToday: Dark Matter Galaxy?
• PPARC: New evidence for a Dark Matter Galaxy
• PTF10fqs: A Luminous Red Nova in the Spiral Galaxy Messier 99
• Messier 99 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Coordinates: 12^h 18^m 49.6^s, +14° 24′ 59″