DUST OBSCURATION IN STARBURST GALAXIES FROM NEAR-INFRARED SPECTROSCOPY

We present new observations of the near-infrared hydrogen recombinatio n lines Pa beta and Br gamma in the central starburst regions of 13 ga laxies. The near-infrared data are supplemented with data on the optic al Balmer line emission and are used to study the geometrical distribu tion of the dust associated with the massive stars. We find that the r eddening toward the starburst regions can be explained by the presence of foreground dust, either homogeneous or clumpy. The result suggests that there is little internal dust in the star-forming site. Mechanis ms like shock waves and outflows produced by supernova explosions and hot star winds can be effective at destroying and removing the dust fr om inside the region.