The extinction curve towards the Galactic Center (Tobias Fritz, Max Planck Institut für Extraterrestrische Physik, Garching, Germany)

First I introduce the Galactic Center in general. For much of the science about the Galactic Center it is important to know the wavelength dependent extinction towards the Galactic Center.
Therefore, I derive the extinction curve towards the Galactic Center from 1 to 19 micron. For the extinction measurement I use fluxes of the HII region (the minispiral) in the Galactic Center. The intrinsic flux ratios of the different tracers of the minispiral are well known and the deviations are caused by extinction.
I use hydrogen emission lines of the minispiral observed by ISO-SWS and SINFONI. As extinction free flux reference I use the 2 cm continuum emission observed by the VLA. I use the  extinction measurement for obtaining a photometric distance to GC.
Further I constrain the dust composition towards the GC by using the wavelength dependence of the extinction.