We have observed extended emission physically associated with 15 out of 16 UC HII regions with large ratios of single-dish to VLA fluxes. We discuss their implications for the age problem of UC HII regions and the evolution of HII regions.
@article{arxiv.astro-ph/0204310,
title = {Hierarchical Structure of HII Regions - Ultracompact, Compact, and Extended Components},
author = {Kee-Tae Kim and Bon-Chul Koo},
journal= {arXiv preprint arXiv:astro-ph/0204310},
year = {2007}
}
Comments
2 pages, To appear in Hot Star Workshop III: The Earliest Phases of Massive Star Birth, ASP Conference Series, 2002, ed. P. A. Crowther