Title:Spectrophotometric distances to Galactic HII regions

Abstract:
We present a catalog of 35 HII regions distributed along the Galactic plane, 24 among them are giant HII 
regions. We have selected these optically obscured star forming regions from the catalogs of Russeil 
(2003), Conti & Crowther (2004) and Bica et al. (2003). In order to make a detailed study of their stellar 
content in the near infrared domain. J, H and Ks-band color images are used to visually inspect each region. 
Color-color and color-magnitude diagrams are used to select candidates in each star forming region for 
follow up spectroscopic investigation. We have obtained Spitzer IRAC images for each region to help further 
characterize them. We use the observed near infrared photometry and Spitzer and near infrared morphology 
to place each cluster in an evolutionary phase of development. Comparison of the main sequence line to 
each observed cluster color magnitude diagram is used to infer whether or not the cluster kinematic 
distance is consistent with brightnesses of the stellar sources. We find qualitative agreement for a dozen of 
the regions but half of the sample have near infrared photometry that suggests they are closer than the 
kinematic distance. A significant fraction of these already have spectroscopic parallaxes which support 
smaller distances.