Messier Index/M99

Messier 99 300px A w:near-infrared image of M99.Credit: w:2MASS/w:NASA. w:Coma BerenicesR. W. Sinnott, editor The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer 1988 Sky Publishing Corporation and Cambridge University Press 0-933-34651-4 w:J2000 SA(s)cNASA/IPAC Extragalactic Database Results for NGC 4254 http://nedwww.ipac.caltech.edu/ 2006-11-25 12 18 49.6 +14 24 59 60 MlyFebruary 2007 2407 ± 3 km/s 10.4 5′.4 × 4′.7 NGC 4254, UGC 7345, PGC 39578, Coma Pinwheel Galaxy,SIMBAD Astronomical Database Results for NGC 4254 http://simbad.u-strasbg.fr/Simbad 2006-11-25 Virgo Cluster Pinwheel Messier 99 (also known as M99 or NGC 4254) is an w:unbarred spiral galaxy approximately 60 million w:light-years away in the w:constellation w: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 w:VIRGOHI21. The gravity from the w:dark galaxy w:VIRGOHI21 appears to 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. thumb|left|500px|Amateur Image of Messier 99 Courtesy Hunter Wilson History Messier 99 was discovered by w:Pierre Méchain on w:March 17, w:1781. The discovery was then reported to w:Charles Messier, who included the object in the w:Messier Catalogue, which was the first astronomical catalogue of star clusters, nebulae, and galaxies.K. G. Jones 1991 Messier's Nebulae and Star Clusters 2nd edition Cambridge University Press Cambridge 0-521-37079-5 Messier 99 was one of the first galaxies in which a spiral pattern was first seen. The spiral pattern was first identified by w:Lord Rosse in the mid-nineteenth century. External links SEDS: Spiral Galaxy M99 UniverseToday: Dark Matter Galaxy? PPARC: New evidence for a Dark Matter Galaxy References