Theory of UC HII regions

Susana Lizano

Centro Radioastronomia y Astrofisica

Hypercompact HII regions may represent phase previous to the development of UC HII regions. I will discuss observed properties of these ionized regions in relation to simple models for their morphology. I will also discuss the effect of dust. I will finally mention the dynamical models that may explain the observed motions in these hypercompact regions.