Is The Milky Way A Grand Design Spiral?

It is difficult to decipher the structure of the Milky Way Galaxy since we reside within the Galactic disk. There is observational evidence that the Milky Way is a Grand Design, barred spiral galaxy with two symmetric spiral arms that are connected to the end of the bar. This is important since bars and spiral arms influence Galactic dynamics and star formation. If the Milky Way is a Grand Design spiral, we should expect to find an equal number and distribution of HII regions at both ends of the bar. We have produced a catalog of "all" Galactic HII regions in the Galaxy using the Wide Infrared Survey Explorer (WISE) and see a significant deficit in the number of HII regions at the end of the Southern bar (20) compared with the Northern bar (132). This is inconsistent with a Grand Design. The line-of-sight to the Southern bar is closer to the Galactic Center than the Northern bar and is more distant. Could opacity be an issue? Are the radio quiet WISE sources really HII regions? We use the Jansky Very Large Array (JVLA) to create a square degree mosaic of the thermal (free-free) emission at 8-10 GHz toward both ends of the bar to confirm this asymmetry and test the completeness of the WISE catalog.