| NGC 5585 | |
|---|---|
 NGC 5585 (Hubble Space Telescope) | |
| Observation data (J2000epoch) | |
| Constellation | Ursa Major |
| Right ascension | 14h 19m 48.2s |
| Declination | +56° 43′ 45″ |
| Redshift | +293 km/s (182 mi/s) |
| Heliocentric radial velocity | 303 +/- 1 km/s |
| Distance | 5.7–8.6 Mpc (18.6–28.0 Mly)[1][2] |
| Apparent magnitude (V) | 11.2 |
| Characteristics | |
| Type | SAB(s)d |
| Size | ~35,000 ly (11,000 pc) |
| Apparent size (V) | 5.8′ × 3.7' |
| Other designations | |
| IRAS 14182+5657,2MASX J14194820+5643445,UGC 9179,MCG +10-20-094,PGC 51210,CGCG 295-045 | |
NGC 5585 is aspiral galaxy located about 28 millionlight-years away from Earth in the constellation ofUrsa Major; it is a member of theM101 Group of galaxies. The galaxy has a diameter of about 35,000 light-years and has a very diffuse disc with almost no central bulge. Although its overall structure is quite complex, the galaxy does have a very faintspiral arm structure which has resulted in it receiving agalaxy morphological classification of SAB(s)d.[3]
Like other galaxies with a similar type, NGC 5585 exhibits a moderate level ofstar formation that is mostly concentrated in the central region. To date, 47 distinct regions of star formation have been identified. Despite this, the galaxy's visible components appear to form only a tiny fraction of the total mass present as the gravity of the visible portion of the disc does not explain the observedrotation curve even extremely close to the center. This suggests that NGC 5585 has a very largedark matter component that is more reflective of what is normally seen indwarf galaxies than a galaxy of this size. Even the gravity of the galaxy'sH I regions appears to have more impact than the visible components of the galaxy.[1][3]
A total of fivesupernova remnants (SNRs) have been observed in NGC 5585. One of the SNRs is extremely large with dimensions of about 200 x 90parsecs (650 x 300 ly) and itsx-ray emissions are so powerful that it actually distorted the initial x-ray emission contour map for the entire galaxy that was obtained by theEinstein Observatory in the early 1980s. The SNR's large size and the fact that it is still expanding at an abnormally high rate of more than 85 km/s (53 mi/s) suggest that it is probably located in a low-density area of NGC 5585'sinterstellar medium.[4]
A 1997 paper estimated that the galaxy probably has about onesupernova every 1,000 years.[4]
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