NGC 4151
NGC 4151 is an intermediate spiral Seyfert galaxy with weak inner ring structure located 15.8 megaparsecs (52 million light-years) from Earth in the constellation Canes Venatici. The galaxy was first mentioned by William Herschel on March 17, 1787; it was one of the six Seyfert galaxies described in the paper which defined the term. It is one of the nearest galaxies to Earth to contain an actively growing supermassive black hole. The black hole would have a mass on the order of 2.5 million to 30 million solar masses. It was speculated that the nucleus may host a binary black hole, with about 40 million and about 10 million solar masses respectively, orbiting with a 15.8-year period. This is, however, still a matter of active debate.
| NGC 4151 | |
|---|---|
Image of NGC 4151 from the 0.8m Schulman Telescope at the Mount Lemmon SkyCenter | |
| Observation data (J2000 epoch) | |
| Constellation | Canes Venatici |
| Right ascension | 12h 10m 32.6s |
| Declination | +39° 24′ 21″ |
| Redshift | 0.003262 995 ± 3 km/s |
| Distance | 15.8 ± 0.4 Mpc (51.5×106 ± 1.3×106 ly) |
| Apparent magnitude (V) | 11.5 |
| Characteristics | |
| Type | (R')SAB(rs)ab, Sy1 |
| Apparent size (V) | 6.4′ × 5.5′ |
| Other designations | |
| UGC 7166, PGC 38739 | |
Some astronomers nickname it the "Eye of Sauron" from its appearance.
One supernova has been observed in NGC 4151: SN 2018aoq (Type II, mag 14.4).