The SiO outflow from IRAS 17233-3603 at high resolution

TL;DR

This study uses high-resolution VLA observations to analyze the complex outflow dynamics in a massive star-forming region, revealing a large-scale outflow influenced by multiple mechanisms including rotation and smaller outflows.

Contribution

It provides a detailed, multi-molecular view of the large-scale outflow in IRAS 17233-3606, highlighting the combined effects of rotation, outflow, and environmental interactions.

Findings

A single large-scale outflow (~0.15 pc) explains the observed molecular dynamics.

Different morphologies of blue and red components relate to envelope structure.

Velocity gradients suggest a mix of rotation and outflow motions.

Abstract

Context: Jets and outflows are key ingredients in the formation of stars across the mass spectrum. In clustered regions, understanding powering sources and outflow components poses a significant problem. Aims: To understand the dynamics in the outflow(s) from a cluster in the process of forming massive stars. Methods: We use new VLA observations of the molecular gas (SiO, CS, OCS and \molec) in the massive star forming region IRAS 17233-3606 which contains a number of HII regions. We compare these observations to previously published molecular data for this source in order to get a holistic view of the outflow dynamics. Results:We find that the dynamics of the various species can be explained by a single large scale ($\sim 0.15$ pc) outflow when compared to the sizes of the HII regions, with the different morphologies of the blue and red outflow components explained with respect to the morphology of the surrounding envelope. We further find that the direction of the velocity gradients seen in OCS and \molec are suggestive of a combination of rotation and outflow motions in the warm gas surrounding the HII regions near the base of the large scale outflow. Conclusions: Our results show that the massive protostars forming within this region appear to be contributing to a single outflow on large scales. This single large scale outflow is traced by a number of different species as the outflow interacts with its surroundings. On the small scales, there appear to be multiple mechanisms contributing to the dynamics which could be a combination of either a small scale outflow or rotation with the dynamics of the large scale outflow.