NGC 5585 

NGC 5585 is a fascinating spiral galaxy located about 28 million light-years away in the constellation Ursa Major. It is a member of the M101 Group of galaxies. The galaxy has a diameter of about 35,000 light-years and features a very diffuse disk with almost no central bulge. Despite its overall complex structure, NGC 5585 has a faint spiral arm structure, which has led to its classification as an SAB(s)d galaxy.

One of the most intriguing aspects of NGC 5585 is its high dark matter content. The visible components of the galaxy form only a tiny fraction of its total mass, as the gravity of the visible portion of the disk does not explain the observed rotation curve, even extremely close to the center. This suggests that NGC 5585 has a very large dark matter component, more reflective of what is normally seen in dwarf galaxies.

The galaxy exhibits a moderate level of star formation, mostly concentrated in the central region. To date, 47 distinct regions of star formation have been identified. NGC 5585 also hosts five supernova remnants (SNRs), one of which is extremely large and still expanding at an abnormally high rate.