| NGC 1947 | |
|---|---|
.jpg) NGC 1947 byHubble Space Telescope | |
| Observation data (J2000epoch) | |
| Constellation | Dorado |
| Right ascension | 05h 26m 47.6s[1] |
| Declination | −63° 45′ 36″[1] |
| Redshift | 0.003669 ± 0.000080[1] |
| Heliocentric radial velocity | 1,100 ± 24km/s[1] |
| Distance | 47.8 ± 11.7Mly (14.65 ± 3.6Mpc)[1] |
| Apparent magnitude (V) | 10.8[2] |
| Characteristics | |
| Type | S0- pec[1] |
| Apparent size (V) | 3.0′ × 2.6′[1] |
| Notable features | Polar-ring |
| Other designations | |
| ESO 085-G87, AM 0526-634, IRAS 05264-6347,PGC 17296[1] | |
NGC 1947 is apeculiarlenticular galaxy in the constellationDorado. The galaxy lies about 50 millionlight years away from Earth, which means, given its apparent dimensions, that NGC 1947 is approximately 75,000 light years across.[1] It was discovered byJames Dunlop on November 5, 1826.[3]
The galaxy is characterised by the presence of dust lanes across the minor axis of the galaxy, indicating it is apolar-ring galaxy.[4] The galaxy has one central dust lane while three more less pronounced lanes are visible which look like concentric rings. Although it is categorised as a lenticular galaxy, it lacks a disk, having thus more in common withelliptical galaxies.[5]
Molecular gas has been detected around the nucleus of the galaxy with an estimated hydrogen mass of4.2×108 M☉.[6] The gas rotates in an axis perpendicular to that of the stars of the galaxy, but in its inner region it is warped. The kinematics suggest that the dust and gas have an external origin, probably accreted from a gas-rich galaxy, as there is a lack oftidal tails that would indicate it is as a result of an unequal massmerger with a disk galaxy.[4]
The nucleus of the galaxy has been found to beactive and it is categorised as aLINER.[7] The most accepted theory for the energy source of active galactic nuclei is the presence of anaccretion disk around asupermassive black hole.
NGC 1947 is the brightest galaxy in theNGC 1947 group, which also includes the galaxies ESO 085–065, ESO 085–088, and ESO 086–010. This group lies close to theDorado Group,[8] and is part of theSouthern Supercluster.[9]
