A Search for Mid-infrared Emission from Hot Molecular Core Candidates

We present here mid-infrared images of seven sites of water maser emission thought to be associated with the hot molecular core (HMC) phase of massive star formation. Observations were obtained at the NASA InfraRed Telescope Facility 3-m, the Gemini 8-m, and Keck II 10-m telescopes. We have detected mid-infrared sources at the locations of two HMC candidates, G11.94-0.62 and G45.07-0.13. We observed G19.61-0.23 and G34.26+0.15, each of which have HMCs previously detected in the mid-infrared. We did not detect mid-infrared emission from either HMC source, and we place new upper limits on the midinfrared flux densities for these HMCs that are much lower than their previously reported flux densities. We were able to obtain extremely accurate astrometry for our mid-infrared images of G9.62+0.19, and conclude that the mid-infrared emission thought to be coming from the HMC in this field is in fact coming from a different source altogether. Subject headings: circumstellar matter – infrared: ISM – stars: early type – stars: formation – masers