Hα line profiles for a sample of supergiant HII regions

III. Model line profiles

Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, CP 22800, Baja California, Mexico e-mail: [maite;richer;wsteffen;ggs;jal]@astrosen.unam.mx

Received: 23 March 2006
Accepted: 15 June 2006

Abstract

We carried out a series of 1D hydrodynamical computations with the ZEUS fluid solver in order to reproduce the salient features in our high-resolution Hα emission line profiles of a sample of HII regions (see Rozas et al. 2006a,b). Four models were computed. In the first and second cases, an ionization-bounded HII region was modeled with and without a shell produced by stellar winds. In the third and fourth cases, a density-bounded HII region was considered, both with and without a shell driven by stellar winds. The resulting line profiles have been modeled using the SHAPE rendering program. We find that our observed high-quality profiles are well-reproduced in the density-bounded model that includes an expanding shell formed as a result of the stellar winds from the ionizing stars. Finally, we consider the effects that the finite slit widths used for the observations have on the physical conditions deduced from the line profile of the ionized bubble.