The Turbulence Velocity Power Spectrum of Neutral Hydrogen in the Small Magellanic Cloud

TL;DR

This study uses the Velocity Coordinate Spectrum technique to analyze the turbulence in the Small Magellanic Cloud, revealing a steep velocity power spectrum and suggesting tidal interactions as a key turbulence driver.

Contribution

It applies the VCS method to 21cm emission data of the SMC, providing new insights into turbulence scales and mechanisms in dwarf galaxies.

Findings

Velocity spectral index of -3.85 indicating shock-dominated turbulence

Injection scale of 2.3 kpc linked to tidal interactions

Turbulence driven by galaxy interactions beyond supernovae

Abstract

We present the results of the Velocity Coordinate Spectrum (VCS) technique to calculate the velocity power spectrum of turbulence in the Small Magellanic Cloud (SMC) in 21cm emission. We have obtained a velocity spectral index of -3.85 and an injection scale of 2.3 kpc. The spectral index is steeper than the Kolmogorov index which is expected for shock-dominated turbulence which is in agreement with past works on the SMC gas dynamics. The injection scale of 2.3 kpc suggests that tidal interactions with the Large Magellanic Cloud are the dominate driver of turbulence in this dwarf galaxy. This implies turbulence maybe driven by multiple mechanisms in galaxies in addition to supernova injection and that galaxy-galaxy interactions may play an important role.