The pinwheel galaxy has been a Hubble Space Telescope favorite for some time now. All the observations are of the gorgeous spiral arm structure of this big galaxy.

Recently, van Dokkum et al found that this galaxy has hardly any stellar halo surrounding it using a new ground-based telescope called the Dragonfly.

This was a really unexpected and cool result. We kind of expect all big galaxies to be surrounded by a halo of older stars, left from their formation.

I wrote a proposal to follow-up with Hubble on this claim to see what the stellar halo and the stellar population of that halo look like. Hubble is the only telescope that can resolve individual stars at this distance.

The figure below shows the 6 fields of my program that will sample M101 halo. The GHOSTS survey pipeline will then process the data later in 2015.