[S IV] in the NGC 5253 Supernebula: Ionized Gas Kinematics at High Resolution

TL;DR

This study uses high-resolution infrared spectroscopy to analyze ionized gas motions in the supernebula of NGC 5253, revealing complex gas flows likely driven by stellar activity.

Contribution

First high-resolution spectral analysis of the supernebula in NGC 5253, demonstrating gas kinematics with multiple velocity components.

Findings

Detection of two Gaussian components in the gas velocity profile.

Evidence for gas flowing out of the molecular cloud, consistent with blister or champagne flow models.

Spectral line widths indicating turbulent and dynamic gas motions.

Abstract

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+3 at 3.8 kms-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-1 and another of similiar strength and FWHM 94 km s-1 centered \sim20 km s-1 to the blue. This suggests a model for the supernebula in which gas flows towards us out of the molecular cloud, as in a "blister" or "champagne flow" or in the HII regions modelled by Zhu (2006).