We present radio-continuum observations at 7 mm made using the Very Large Array toward three massive star-forming regions thought to be in very early stages of evolution, selected from the 2002 sample of Sridharan et al. Emission was detected toward all three sources (IRAS 18470-0044, IRAS 19217+1651, and IRAS 23151+5912). We find that in all cases the 7 mm emission corresponds to thermal emission from ionized gas. The regions of ionized gas associated with IRAS 19217+1651 and IRAS 23151+5912 are hypercompact, with diameters of 0.009 and 0.0006 pc and emission measures of 7.0 × 108 and 2.3 × 109 pc cm-6, respectively.
展开▼
