M81 star cluster candidates

We have found 233 good globular cluster (GC) candidates; 92 candidate HII regions, OB associations, or diffuse open clusters; 489 probable background galaxies; and 1719 unclassified objects. We have color data from ground-based g- and r-band MMT Megacam images for 79 galaxies, 125 GC candidates, 7 HII regions, and 184 unclassified objects.

The color-color diagram of GC candidates shows that most fall into the range 0.25<g-r<1.25 and 0.5<r-I<1.25, similar to the color range of Milky Way GCs. Unclassified objects are often blue, suggesting that many of them are likely to be HII regions and open clusters, although a few galaxies and GCs may be among them.