|Right Ascension||12 : 40.0 (h:m)
|Declination||-11 : 37 (deg:m)
|Visual Brightness||8.0 (mag)
|Apparent Dimension||9x4 (arc min)
Discovered by Pierre Méchain or Charles Messier in 1781.
M104 is numerically the first object of the catalog which was not included in Messier's originally published catalog. However, Messier added it by hand in his personal copy on 11th May 1781 as a "very faint nebula." It was Flammarion who found that its position coincided with Herschel's H I.43, which is the Sombrero galaxy, and added it to the official Messier list. William Herschel found this object independently on May 9, 1784.
This brilliant galaxy was named the Sombrero Galaxy because of its appearance. According to de Vaucouleurs, we view it from just 6 degrees south of its equatorial plane, which is outlined by a rather thick dark rim of obscuring dust. This dust lane was probably the first discovered, by William Herschel in his great reflector.
This galaxy is of type Sa-Sb, with both a big bright core, and as one can see in shorter exposures, also well-defined spiral arms. It also has an unusually pronounced bulge with an extended and richly populated globular cluster system - several hundred can be counted in long exposures from big telescopes.
Recent very deep photographs from the Anglo-Australian Observatory show that this galaxy has a very extended faint halo.
This galaxy was the first one with a large redshift found, by Vesto M. Slipher at Lowell Observatory in 1912. Its redshift corresponds to a recession velocity of about 1,000 km/sec (it is caused by the Hubble effect, i.e. the cosmic expansion). This was too fast for the Sombrero to be an object in our Milky Way galaxy. Slipher also detected the galaxy's (then the nebula's) rotation.
Last Modification: 9 Dec 1999, 22:59 MET