Dark matter in Dwarf and Low Surface Brightness Galaxies

Dwarf and LSB galaxies are usually believed to be dominated by dark matter. Based on new observations of a large sample of these galaxies we found that their rotation curves have shapes similar to those of spiral galaxies. Despite their lower amplitudes, the rotation curves rise steeply until about two disk scale lengths, and start to reach a flat part at larger radii. Mass models based on these rotation curves are consistent with a wide range in their dark matter properties: on the one hand, these rotation curves are consistent with dwarf galaxies being dominated by dark matter. On the other they may also have dark matter properties similar to those of spiral galaxies.