In the NGC5253 supernebula: Ionized gas kinematics at high resolution

Abstract

The nearby dwarf starburst galaxy NGC5253 hosts a deeply embedded radio-infrared supernebula excited by thousands of O stars. We have observed this source in the 10.5 μm line of S +3 at 3.8kms-1 spectral and 14 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 33.6kms-1 and another of similar strength and FWHM 94kms-1 centered 20kms-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. © © 2012. The American Astronomical Society. All rights reserved..