NIR studies of galactic giant HII regions

We present results from our ongoing survey of Galactic Giant HII Regions in the near-infrared. The luminosity function indicates that the IMF is uniform, independent of the galactocentric distance and compatible with Salpeter (1955) slope. Distances measured by the spectroscopic parallax method are systematically smaller than kinematic distances derived from radio techniques. As a consequence, the number of ionizing photons and the star formation rate is much lower than that derived from rotation models. Although the luminosities of the giant HII regions obtained from this method are lower than by other methods, the morphological type of the Milky Way is well in line of previous results, close to Sbc or Sc types.