UGC 12591
Spiral Galaxy in Pegasus
From Wikipedia, the free encyclopedia
UGC 12591 is a spiral galaxy in the constellation Pegasus. Its velocity with respect to the cosmic microwave background is 6,600±24 km/s, which corresponds to a Hubble distance of 317.5 ± 22.2 Mly (97.35 ± 6.82 Mpc).[1] However, five non-redshift measurements give a farther mean distance of 394.26 ± 59.86 Mly (120.880 ± 18.352 Mpc).[3] The first known reference to this galaxy comes from Part 2 of the Morphological Catalogue of Galaxies, published in 1964, where it is listed as MCG +05-55-015.[4]
| UGC 12591 | |
|---|---|
UGC 12591 imaged by the Hubble Space Telescope | |
| Observation data (J2000 epoch) | |
| Constellation | Pegasus |
| Right ascension | 23h 25m 21.7979s[1] |
| Declination | +28° 29′ 43.281″[1] |
| Redshift | 0.023166[1] |
| Heliocentric radial velocity | 6945 ± 3[1] |
| Distance | 394.26 ± 59.86 Mly (120.880 ± 18.352 Mpc)[1] |
| Apparent magnitude (B) | 13.90[1] |
| Characteristics | |
| Type | S0/a[1] |
| Mass | 1.9×1012[2] M☉ |
| Size | ~273,300 ly (83.80 kpc) (estimated)[1] |
| Apparent size (V) | 1.7′ × 0.7′[1] |
| Other designations | |
| MCG +05-55-015, PGC 71392, CGCG 497-015[1] | |
UGC 12591 is the spiral galaxy with the highest known rotational speed[2] of about 500 km/s, almost twice that of the Milky Way galaxy. The high rotational speed means the galaxy must be very massive at the center; the galaxy has a mass estimated at 4 times that of the Milky Way.[5]
UGC 12591 is relatively isolated; the nearest galaxy to it, WISEA J232529.77+283021.3, is 3.55 million light-years (1.09 Mpc) away. However, its morphology suggests a merger or accretion event in its past: it is somewhat lenticular-like, with a central bulge and dust lanes reminiscent of the Sombrero Galaxy.[6]
