Sombrero Galaxy
The Sombrero Galaxy (also known as Messier Object 104, M104 or NGC 4594) is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs (31.1 million light-years) from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs (94,900 to 105,000 light-years), making it slightly bigger in size than the Milky Way.
| Sombrero Galaxy | |
|---|---|
Image taken by Hubble Space Telescope, May−June 2003 | |
| Observation data (J2000 epoch) | |
| Constellation | Virgo |
| Right ascension | 12h 39m 59.4s |
| Declination | −11° 37′ 23″ |
| Redshift | 0.003416±0.000017 |
| Heliocentric radial velocity | 1,024±5 km/s |
| Galactocentric velocity | 904±7 km/s |
| Distance | 9.55 ± 0.31 Mpc (31.1 ± 1.0 Mly) |
| Apparent magnitude (V) | 8.0 |
| Absolute magnitude (B) | −21.8 |
| Characteristics | |
| Type | SA(s)a or E |
| Size | 32.32 kpc × 17.45 kpc (105.4 kly × 56.91 kly) (diameter; 2MASS K-band total isophote) 29.09 kpc (94.88 kly) (diameter; D25.0 B-band isophote) |
| Apparent size (V) | 9′ × 4′ |
| Notable features | Unusually bright center, intriguingly detailed dust band |
| Other designations | |
| M104, NGC 4594, UGC 293, PGC 42407 | |
It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its outer disk, which is viewed almost edge-on. The dark dust lane and the bulge give it the appearance of a sombrero hat (thus the name). Astronomers initially thought the halo was small and light, indicative of a spiral galaxy; but the Spitzer Space Telescope found that the dust ring was larger and more massive than previously thought, indicative of a giant elliptical galaxy.
The galaxy has an apparent magnitude of +8.0, making it easily visible with amateur telescopes, and is considered by some authors to be the galaxy with the highest absolute magnitude within a radius of 10 megaparsecs of the Milky Way. Its large bulge, central supermassive black hole, and dust lane all attract the attention of professional astronomers.