NGC 5557 | |
---|---|
Observation data ( J2000 epoch) | |
Constellation | Boötes |
Right ascension | 14h 18m 25.708s [1] |
Declination | +36° 29′ 37.28″ [1] |
Redshift | 0.010764 [2] |
Heliocentric radial velocity | 3210 ± 28 km/s [2] |
Distance | 127 Mly (38.8 Mpc) [3] |
Apparent magnitude (V) | 12.2 [4] |
Absolute magnitude (V) | −22.39 [5] |
Characteristics | |
Type | E1 [3] |
Other designations | |
UGC 9161, MCG +06-31-093, PGC 51104 [2] |
NGC 5557 is an elliptical galaxy in the constellation Boötes. It was discovered by William Herschel on May 1, 1785. [4] The distance to NGC 5557 is not well known, but it is estimated to be about 127 million light-years (38.8 megaparsecs) away. [3]
NGC 5557 is quite massive, with a K-band absolute magnitude of −24.8, and is a slow rotator, [3] which suggests it gained mass through dry mergers (galaxy mergers involving galaxies significant amounts of gas). [5] However, it has a faint tidal tail to its east, as well as a more complex structure to the west. This structure, if found to be connected to NGC 5557, would one of the largest around a galaxy, spanning about 1.1 million light-years (350,000 parsecs). [3] This filamentary structure suggests that NGC 5557 may have formed from a more gas-rich galaxy merger a couple billion years ago. [3] This implies that the galaxy merger would need to have a low impact parameter. [5]
NGC 5557 is part of a galaxy group, [3] [4] and is the largest such galaxy in the group by far. [3] Surrounding the galaxy near the eastern filament are several small bluish objects, which are possibly tidal dwarf galaxies. [3]
Two supernovae have been observed in NGC 5557: SN 1996aa ( type Ia, mag. 17), [6] and SN 2013gn (type Ia, mag. 15.3). [7]
NGC 5557 | |
---|---|
Observation data ( J2000 epoch) | |
Constellation | Boötes |
Right ascension | 14h 18m 25.708s [1] |
Declination | +36° 29′ 37.28″ [1] |
Redshift | 0.010764 [2] |
Heliocentric radial velocity | 3210 ± 28 km/s [2] |
Distance | 127 Mly (38.8 Mpc) [3] |
Apparent magnitude (V) | 12.2 [4] |
Absolute magnitude (V) | −22.39 [5] |
Characteristics | |
Type | E1 [3] |
Other designations | |
UGC 9161, MCG +06-31-093, PGC 51104 [2] |
NGC 5557 is an elliptical galaxy in the constellation Boötes. It was discovered by William Herschel on May 1, 1785. [4] The distance to NGC 5557 is not well known, but it is estimated to be about 127 million light-years (38.8 megaparsecs) away. [3]
NGC 5557 is quite massive, with a K-band absolute magnitude of −24.8, and is a slow rotator, [3] which suggests it gained mass through dry mergers (galaxy mergers involving galaxies significant amounts of gas). [5] However, it has a faint tidal tail to its east, as well as a more complex structure to the west. This structure, if found to be connected to NGC 5557, would one of the largest around a galaxy, spanning about 1.1 million light-years (350,000 parsecs). [3] This filamentary structure suggests that NGC 5557 may have formed from a more gas-rich galaxy merger a couple billion years ago. [3] This implies that the galaxy merger would need to have a low impact parameter. [5]
NGC 5557 is part of a galaxy group, [3] [4] and is the largest such galaxy in the group by far. [3] Surrounding the galaxy near the eastern filament are several small bluish objects, which are possibly tidal dwarf galaxies. [3]
Two supernovae have been observed in NGC 5557: SN 1996aa ( type Ia, mag. 17), [6] and SN 2013gn (type Ia, mag. 15.3). [7]