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R. A. Gaume (U.S. Naval Obs.), M. Lindqvist, J. H. Black (Onsala Space Obs.), F. J. Vrba, A. A. Henden, H. H. Guetter (U.S. Naval Obs., Flagstaff Station)
Near-infrared images of the G34.3+0.2 region of star formation are presented. The coordinate frame of each of the near-infrared 1.3 micron (J-band), 1.7 micron (H-band), 2.2 micron (K-band), and 3.5 micron (L-band) images has been astrometrically aligned with the radio coordinate frame, allowing a detailed comparison between the infrared and radio sources found in the G34.3+0.2 star forming region. The strongest 2.2 micron feature, which has an arc-like shape, is centered approximately 3 arcseconds south of the cm wavelength radio continuum cometary-like HII region, G34.3+0.2 C. This 2.2 micron feature appears to have minimal spatial overlap with the radio continuum, and may be a reflection nebula. At the location of the cometary-like radio HII region, there is only a very weak 2.2 micron source. In contrast, the strongest 3.5 micron feature toward the radio HII region is spatially coincident with the intensity peak of the cometary radio HII region. When compared to the expected near-infrared flux density predicted by mid-infrared dust shell models, the flux density calibrated 2.2 and 3.5 micron images show significant excess emission. At the position of the radio continuum intensity peak, a <1 arcsecond diameter broken toroid-like structure is seen in both the 2.2 and 3.5 micron images. The toroidal feature, taken together with the 2.2 and 3.5 micron flux density excess, suggests the existence of a hot circumstellar disk associated with the exciting star of the G34.3+0.2 C cometary radio HII region.
The author(s) of this abstract have provided an email address for comments about the abstract: rgaume@usno.navy.mil