High Sensitivity VLA Continuum Observations of G29.96$-$0.02

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Session 82 -- HII Regions
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

[82.11] High Sensitivity VLA Continuum Observations of G29.96$-$0.02

A. Fey, R. Gaume (USNO), M. Claussen (NRAO)

Cometary HII regions are characterized by a strong edge--brightened core (the ``head'') with a low surface brightness ``tail'' of emission trailing off opposite the bright edge. We present multiple configuration, 15 GHz VLA continuum observations of the HII region G29.96$-$0.02. This source has been previously morphologically classified as ``cometary'' by various investigators. Our data, which are more sensitive to low surface brightness extended emission than any previous observation of this source, show a complex structure. The $\sim5''$ edge--brightened core of the HII region is embedded in low level emission extending over $\sim15''-25''$. Filamentary--like structures are observed perpendicular to the symmetry axis of the head, suggestive of an asymmetrically edge--brightened shell source. Additional filamentary--like structures are seen as far away as $\sim35''$ from the core. These observations are inconsistent with existing models for cometary HII regions. Interpretation in terms of a new photo--evaporation model will be discussed.

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