Abstract
We present VLA continuum observations of 12 luminous IRAS sources with no previously detected or relatively weak centimeter continuum emission. Given these characteristics, the observed sources could be massive hot cores, containing OB stars in the early stages of formation. All the sources were observed at 3.6 cm and five of them were also observed at 7 mm. With one exception (IRAS 20216+4107), all sources were detected at 3.6 cm. Five of these detections are reported here for the first time. The centimeter continuum emission is consistent with that expected from photoionization by the more massive members of stellar clusters with the observed luminosities. However, other explanations (e.g., thermal jets) are possible for the relatively weak continuum emission observed. No 7 mm emission was detected in the five sources observed.
