NGC 4947
| Galaxy NGC 4947 / IC 3974 |
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|---|---|
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| AladinLite | |
| Constellation | centaur |
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Position equinox : J2000.0 , epoch : J2000.0 |
|
| Right ascension | 13 h 05 m 20.2 s |
| declination | -35 ° 20 ′ 15 ″ |
| Appearance | |
| Morphological type | SA (r) bc / HII |
| Brightness (visual) | 11.9 likes |
| Brightness (B-band) | 12.7 mag |
| Angular expansion | 2.4 ′ × 1.2 ′ |
| Position angle | 10 ° |
| Surface brightness | 12.9 mag / arcmin² |
| Physical data | |
| Affiliation | LGG 327 |
| Redshift | 0.008036 ± 0.000024 |
| Radial velocity | 2409 ± 7 km / s |
|
Stroke distance v rad / H 0 |
(100 ± 7) x 10 6 ly (30.8 ± 2.2) Mpc |
| history | |
| discovery | John Herschel |
| Discovery date | May 1, 1834 |
| Catalog names | |
| NGC 4947 • IC 3974 • PGC 45269 • ESO 382-005 • MCG -06-29-006 • IRAS 13025-3504 • 2MASX J13052020-3520147 • SGC 130234-3504.2 • GC 3388 • h 3461 • HIPASS J1305-35 | |
NGC 4947 = IC 3974 is a 11.9 mag bright bar-spiral galaxy with extensive star formation regions of the Hubble type "SBb" in the constellation Centaur in the southern sky . It is estimated to be 100 million light years away from the Milky Way and has a diameter of about 75,000 ly . Together with NGC 4947A and PGC 44770 , it forms the small galaxy group LGG 327.
The object was discovered twice; first on May 1, 1834 by John Herschel with an 18-inch reflector telescope , who noted "pretty large, faint, round, very gradually a little brighter in the middle, 50 arcseconds" (discovery listed as NGC 4947 ); then on March 28, 1898 by Lewis A. Swift (listed as IC 3974 ).
NGC 4947 group ( LGG 327 )
| Galaxy | Alternative name | Distance / million Lj |
|---|---|---|
| NGC 4947 | PGC 45269 | 100 |
| NGC 4947A | PGC 45180 | 108 |
| PGC 44770 | ESO 381-41 | 108 |