EXPLORING THE NATURE OF COMPACT RADIO SOURCES ASSOCIATED TO UCHII REGIONS

We present Very Large Array 7 mm continuum observations of four Ultra-Compact (UC)HII regions, observed previously at 1.3 cm, in order to investigate the nature compact radio sources associated with these regions. detected a total seven sources, them thermal emission, and two have clear non-thermal emission. The emission is consistent presence an ionized envelope, either static (i.e., trapped gravitational radius massive star) or flowing away photo-evaporative flow). On other hand, remains unclear several possibilities are proposed. possibility that most photo-evaporating objects remaining ones more-evolved previous studies on UCHII