"Dwarf galaxies" refers to small galaxies that are much smaller in size and have fewer stars compared to regular-sized galaxies. They are like tiny versions of galaxies, but still have their own collection of stars, gas, and dust. Full definition
What's promising about dark atoms is that they could explain the lack of dwarf galaxies in our observations. (newscientist.com)
One of the key science drivers for the extension was the study of proper motions of stars in dwarf galaxies, which requires observations taken over as long a time baseline as possible. (astronomynow.com)
A large galaxy should be surrounded by numerous faint dwarf galaxies which get most of their mass from dark matter. (newscientist.com)