[S IV] IN THE NGC 5253 SUPERNEBULA: IONIZED GAS KINEMATICS AT HIGH RESOLUTION

The nearby dwarf starburst galaxy NGC 5253 hosts a deeply embedded radio-infrared supernebula excited by thousands of O stars. We have observed this source in the 10.5 mu m line of S super(+3) at 3.8 km s super(-1) spectral and 1".4 spatial resolution, using the high-resolution spectrometer TEXES on the IRTF. The line profile cannot be fit well by a single Gaussian. The best simple fit describes the gas with two Gaussians, one near the galactic velocity with FWHM 33.6 km s super(-1) and another of similar strength and FWHM 94 km s super(-1) centered ~20 km s super(-1) to the blue. This suggests a model for the supernebula in which gas flows toward us out of the molecular cloud, as in a "blister" or "champagne flow" or in the H II regions modelled by Zhu.