Program: GN-2013B-Q-100

The absorption and reemission of light by dust in HII regions is of profound importance to astronomy because the reradiated light dominates the IR emission. The absorption characteristics can be easily examined in two ways: via the near infrared extinction law, or the mid infrared silicate absorption. The relationship between these quantities is an important clue as to the characteristics of the extinguishing dust. Prompted by unexpected results for another nearby HII region, we propose a study of the Galactic HII region W3A in order to determine the spatial layout of its near infrared extinction using Gemini/NIRI narrow band imaging of hydrogen recombination lines. We will compare these results with our mid infrared observations in order to understand the relationship between the two and test whether the unexpected trends found previously are continued in W3.