| Dwingeloo 2 | |
|---|---|
 | |
| Observation data (J2000epoch) | |
| Constellation | Cassiopeia |
| Right ascension | 02h 54m 08.47s[1] |
| Declination | +59° 00′ 19.1″[1] |
| Heliocentric radial velocity | 94 ± 1.5 km/s[2] |
| Galactocentric velocity | 241 km/s[2] |
| Distance | ~10Mly (3Mpc)[3] |
| Group orcluster | IC 342/Maffei |
| Apparent magnitude (V) | 16.21 (V-band)[4] |
| Characteristics | |
| Type | IAm |
| Apparent size (V) | 2' × 0'.8[1] |
| Notable features | Companion ofDwingeloo 1 |
| Other designations | |
| PGC 101304[1] | |
Dwingeloo 2 is a smallirregular galaxy discovered in 1996 and located about 10 millionlight-years away from the Earth. Its discovery was a result of the Dwingeloo Obscured Galaxy Survey (DOGS) of theZone of Avoidance using theDwingeloo Radio Observatory. Dwingeloo 2 is a companion galaxy ofDwingeloo 1.[2]
Dwingeloo 2 was first detected atradiowavelengths from the21 cmemission line of neutralatomichydrogen (known toastronomers as HI) in the course of follow-up observations after the discovery of Dwingeloo 1.[2] Dwingeloo 2 is thought to be a member of theIC 342/Maffei Group, agalaxy group adjacent to theLocal Group.[3] The galaxy recedes from the Milky Way at the speed of about 241 km/s.[2]
The visible radius of Dwingeloo 2 is approximately 2′, which at the distance of 3 Mpc corresponds to about 2 kpc.[1] Dwingeloo 2 has a well defined rotating HI disk inclined at approximately 69° with respect to observer. The distribution of the neutral hydrogen in Dwingeloo 2 is quite irregular, and it is detected as far as 3.2 kpc from the center of the galaxy. The total mass of the galaxy within this radius is estimated at 2.3 billion Solar masses, while the mass of the neutral hydrogen is estimated at 100 millionSolar masses. The total mass of the galaxy is about five times less than that of Dwingeloo 1.[2]
The irregular structure of Dwingeloo 2 is likely related to its interaction with the much larger nearby galaxy Dwingeloo 1, which lies at a distance of only 24 kpc from Dwingeloo 2.[2]
