NGC 3258
Galaxy in the constellation Antlia
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NGC 3258 is a giant elliptical galaxy[6] in the southern constellation of Antlia.[7] It was discovered by British astronomer John Herschel on May 2, 1834.[8] NGC 3258 is one of the two brightest members of the Antlia Cluster,[9] which lies about 40.7 megaparsecs (132.7 million light-years) away from the Milky Way.[4] It is the namesake of the sparse NGC 3258 group of galaxies that includes the elliptical galaxy NGC 3260 and barred spiral NGC 3257.[10]
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| NGC 3258 | |
|---|---|
NGC 3258 (center) imaged by the Víctor M. Blanco Telescope | |
| Observation data (J2000 epoch) | |
| Constellation | Antlia |
| Right ascension | 10h 28m 53.588s[1] |
| Declination | −35° 36′ 19.98″[1] |
| Redshift | 0.009357[2] |
| Heliocentric radial velocity | 2,792±28 km/s[2] |
| Distance | 124.3 Mly (38.11 Mpc)[3] |
| Group or cluster | Antlia Cluster[4] |
| Apparent magnitude (V) | 11.72[2] |
| Apparent magnitude (B) | 12.50[2] |
| Characteristics | |
| Type | E1[2] |
| Size | ~193,900 ly (59.45 kpc) (estimated)[5] |
| Apparent size (V) | 2.9′ × 2.5′[5] |
| Other designations | |
| ESO 375- G 037, NGC 3258, LEDA 30859, MCG -06-23-032, PGC 30859[2] | |
The morphological classification of NGC 3258 is E1, which indicates it displays a mild ellipticity. It is a weak, extended radio source. Photometry shows a disk of dust around the center of the galaxy, which is aligned with the major axis. There is a heated component of this disk with a mass of 48 M☉ within a radius of 5.5 kpc, which may indicate star formation. Based on a lack of X-ray emission, there is no indication of activity at the center.[9][11]
ALMA observations of the cold gas disk near the supermassive black hole at the core provide a mass estimate of 2.249×109 M☉ with an uncertainty of 0.18%.[12] Spectroscopic observations of star motions near the core yield an independent mass estimate of (2.2±0.2)×109 M☉,[13] which is a good match to the ALMA estimate.
NGC 3258 has an extensive population of globular clusters that is estimated at 6000±150.[6][14] A population of 23 ultra-compact dwarfs have been identified in the vicinity of NGC 3258, some of which may be former dwarf galaxies that have been captured and stripped during minor merger events.[15] These objects provide a mass estimate of 2.7×1012 M☉ within a radius of around 47 kpc from the galactic center.[16]
One supernova has been observed in NGC 3258. The type Ia supernova SN 2010hx was discovered by Berto Monard on September 16, 2010 at a magnitude of 15.3.[17][18]