Malin 1 | |
---|---|
Observation data ( J2000.0 [1] epoch) | |
Constellation | Coma Berenices [2] |
Right ascension | 12h 36m 59.34697s [1] |
Declination | +14° 19′ 49.1585″ [1] |
Redshift | 0.082702±0.000013 [3] |
Heliocentric radial velocity | 24750±10 km/s [3] |
Galactocentric velocity | 24707±10 km/s [3] |
Apparent magnitude (V) | 15.809±0.009 [3] |
Absolute magnitude (V) | −22.01±0.50 [3] |
Characteristics | |
Type | SB0a [1] |
Mass | ~1012 [4] M☉ |
Size | 34.11 to 36.39
kpc (111,250 to 118,690 ly) (diameter; D25.0 B-band and 2MASS K-band total isophotes) [3] [a] |
Apparent size (V) | 0.25 ′ × 0.23 ′ [3] |
Notable features | Surrounded by a H I disk |
Other designations | |
PGC 42102, LEDA 42102, VPC 1091, 2MASX J12365934+1419494, Gaia DR2 3932516418935413504 [1] |
Malin 1 is a giant low surface brightness (LSB) spiral galaxy. [1] [5] It is located 1.19 billion light-years (366 Mpc) away in the constellation Coma Berenices, near the North Galactic Pole. As of February 2015 [update], it is the largest known spiral galaxy, with an approximate diameter of 650,000 light-years (200,000 pc), [6] [7] [8] thus over six times the diameter of our Milky Way. It was discovered by astronomer David Malin in 1986 and is the first LSB galaxy verified to exist. [5] [8] [6] Its high surface brightness central spiral is 30,000 light-years (9,200 pc) across, with a bulge of 10,000 light-years (3,100 pc). [6] The central spiral is a SB0a type barred-spiral. [6]
Malin 1 is peculiar in several ways: its diameter alone would make it the largest barred spiral galaxy ever to have been observed. [4]
Malin 1 was found later to be interacting with two other galaxies, Malin 1B and SDSS J123708.91+142253.2. Malin 1B is located 46,000 light-years (14,000 pc) away from the high surface brightness central spiral of Malin 1, which may be responsible for the formation of the galaxy's central bar. Meanwhile, SDSS J123708.91+142253.2 is located within the huge, faint halo of Malin 1 and might have caused the formation of the extended low surface brightness disc through tidal stripping.
Observations by Galaz et al. in April 2014 revealed a detailed view of the spiral structure of Malin 1 in optical bands. The galaxy exhibits giant and very faint spiral arms, with some segments up to 33,000 light-years (10,000 pc) in diameter. Other details, such as possible stellar streams and formation regions, are revealed as well. [9] The same authors also say that Malin 1 is larger than thought, with another estimated diameter of around 750,000 light-years (230,000 pc). [9]