The Use of Near Infrared Extinction to Constrain the Dusty Spiral Structure of the Milky Way

We present a method to determine the three dimensional extinction distribution along the line of sight. Stellar observations from 2MASS are compared to simulated observations from a 3D Galactic model. The extinction as a function of distance for each line of sight is that which minimises the difference in the near infrared colour distribution between the observed and simulated stars. Using this technique, a large part of the plane of the Milky Way has been mapped. The resulting face on view of the Galactic plane clearly shows the spiral arm tangents and it is possible to fit model spiral arms to the derived dust density map. Future work will involve using the GLIMPSE point source catalogue in order to probe extinction features further through the dusty disc of the Milky Way