Are supernovae driving turbulence in the solar neighborhood?

TL;DR

This study investigates whether supernovae can sustain the observed turbulence in the interstellar medium near the Sun by comparing observations with numerical simulations including different turbulent drivers.

Contribution

It demonstrates that supernova feedback alone underpredicts turbulence levels, while large-scale forcing can match observed velocity dispersions.

Findings

Supernova-driven simulations yield velocity dispersions of 4.9-6.7 km/s.

Large-scale forcing reproduces the observed median velocity dispersion of 11.1 km/s.

Supernovae alone are insufficient to sustain observed turbulence levels.

Abstract

Turbulence plays an important role in shaping the interstellar medium, and strongly influences star formation. We aim to identify the physical processes capable of sustaining HI turbulence in the solar neighborhood. We compare recent HI line-of-sight velocity observations within a volume of radius 70-500 pc centered on the Sun with a suite of 1 kpc numerical simulations that include two distinct turbulent drivers: (i) supernova (SN) feedback and (ii) imposed large-scale turbulent forcing. For each simulation, we construct synthetic sky maps that closely mimic the observational one, allowing for a consistent comparison between the simulations and the observational data. HI observations show a median velocity dispersion of 11.1 km s-1 in the solar neighborhood. SN-driven simulations systematically underpredict this value, yielding dispersions in the range 4.9-6.7 km s-1. Simulations with strong enough large-scale forcing can reproduce not only the median observed velocity dispersion, but also the observed velocity distribution.