Extinction by dust is a major systematic error in measuring star formation rates in galaxies. Using images taken in Paschen-beta in the near infrared and combining this with H-alpha imaging in the visible,it is possible to derive accurate mapping of nebular extinction, and hence massive star formation in nearby galaxies.
As a pilot study to determine the efficacy of this approach, in April 2007 we obtained narrow band images through a Paschen-beta and continuum filter of the nearby massive spiral galaxy M83 (NGC5236).
Results to follow