A "universal" supernova efficiency to drive the HI turbulence in nearby star-forming galaxies
Abstract
The origin of cold gas turbulence in galaxies has long been debated. Supernovae (SNe), the dominant form of stellar feedback, were thought insufficient to sustain it against dissipation, especially in galactic environments with low star formation rates (SFRs). We investigate the origin of the neutral atomic gas (HI) turbulence in dwarf irregular galaxies, a challenging regime of low masses and SFRs. We build on a recent study of spirals showing that disc flaring prolongs the dissipation timescale, reducing the energy needed to sustain turbulence and making SN feedback viable. We measure the SN efficiency, that is the fraction of SN energy required to sustain HI turbulence, in 14 dwarfs, and test whether a "universal" efficiency holds across a sample representative of the star-forming main sequence. From the observed HI distributions and kinematics, we derive the radial profiles of the HI kinetic energy per unit area and model them as the sum of thermal energy and turbulent energy from SNe, constrained by the observed SFR surface density. We consider pure cold and warm neutral medium (WNM) phases as limiting cases, as well as a mixed two-phase scenario, obtaining the SN efficiency and WNM fraction via hierarchical Bayesian inference. We find that the observed HI kinetic energy in dwarfs requires only ≲ 3% of the SN energy, and that a "universal" efficiency of ≈ 2% explains the HI turbulence across our main-sequence sample. Our findings suggest that the SN efficiency remains similar across galaxies with different properties, offering valuable constraint for feedback recipes in galaxy evolution models.
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BibTeX
@misc{sassali2026universal,
title = {{A "universal" supernova efficiency to drive the HI turbulence in nearby star-forming galaxies}},
author = {Lauri Sassali and Cecilia Bacchini and Aku Venhola and Giuliano Iorio and Antonino Marasco},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10698},
eprint = {2610.10698},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10698},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A "universal" supernova efficiency to drive the HI turbulence in nearby star-forming galaxies
AU - Lauri Sassali
AU - Cecilia Bacchini
AU - Aku Venhola
AU - Giuliano Iorio
AU - Antonino Marasco
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10698
UR - https://arxiv.org/abs/2610.10698
AB - The origin of cold gas turbulence in galaxies has long been debated. Supernovae (SNe), the dominant form of stellar feedback, were thought insufficient to sustain it against dissipation, especially in galactic environments with low star formation rates (SFRs). We investigate the origin of the neutral atomic gas (HI) turbulence in dwarf irregular galaxies, a challenging regime of low masses and SFRs. We build on a recent study of spirals showing that disc flaring prolongs the dissipation timescale, reducing the energy needed to sustain turbulence and making SN feedback viable. We measure the SN efficiency, that is the fraction of SN energy required to sustain HI turbulence, in 14 dwarfs, and test whether a "universal" efficiency holds across a sample representative of the star-forming main sequence. From the observed HI distributions and kinematics, we derive the radial profiles of the HI kinetic energy per unit area and model them as the sum of thermal energy and turbulent energy from SNe, constrained by the observed SFR surface density. We consider pure cold and warm neutral medium (WNM) phases as limiting cases, as well as a mixed two-phase scenario, obtaining the SN efficiency and WNM fraction via hierarchical Bayesian inference. We find that the observed HI kinetic energy in dwarfs requires only ≲ 3% of the SN energy, and that a "universal" efficiency of ≈ 2% explains the HI turbulence across our main-sequence sample. Our findings suggest that the SN efficiency remains similar across galaxies with different properties, offering valuable constraint for feedback recipes in galaxy evolution models.
ER -