Work by graduate student Colin Slater and Prof. Eric Bell was recently highlighted by the journal Nature.
The Monoceros Ring is an area near edge of our galaxy with more stars than expected. Astronomers have been debating the origin of this “stellar overdensity” since its discovery in 2002. Slater, Bell, and their colleagues observed the Monoceros Ring using the Pan-STARRS1 telescope in Hawaii, hoping to narrow down the possible models for its formation. Unfortunately, their observations showed features that create problems for both models, indicating there is quite a bit more work to do before we understand how this structure formed.
Understanding its origin will help us understand how structures develop in spiral galaxies in general.
Read "Fresh look at Galactic rim"