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arXiv · 2005.04874

The SAMI Galaxy Survey: Gas velocity dispersions in low-$z$ star-forming galaxies and the drivers of turbulence

Mathew R. Varidel·Scott M. Croom·Geraint F. Lewis·Deanne B. Fisher·Karl Glazebrook·Barbara Catinella·Luca Cortese·Mark R. Krumholz·Joss Bland-Hawthorn·Julia J. Bryant·Brent Groves·Sarah Brough·Christoph Federrath·Jon S. Lawrence·Nuria P. Lorente·Matt S. Owers·Samuel N. Richards·Ángel R. López-Sánchez·Sarah M. Sweet·Jesse van de Sande·Sam P. Vaughan
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Abstract

We infer the intrinsic ionised gas kinematics for 383 star-forming galaxies across a range of integrated star-formation rates (SFR $\in [10^{-3}, 10^2]$ M$_\odot$ yr$^{-1}$) at $z \lesssim 0.1$ using a consistent 3D forward-modelling technique. The total sample is a combination of galaxies from the SAMI Galaxy Survey and DYNAMO survey. For typical low-$z$ galaxies taken from the SAMI Galaxy Survey, we find the vertical velocity dispersion ($σ_{v, z}$) to be positively correlated with measures of star-formation rate, stellar mass, HI gas mass, and rotational velocity. The greatest correlation is with star-formation rate surface density ($Σ_\text{SFR}$). Using the total sample, we find $σ_{v, z}$ increases slowly as a function of integrated star-formation rate in the range SFR $\in$ [$10^{-3}$, 1] M$_\odot$ yr$^{-1}$ from $17\pm3$ km s$^{-1}$ to $24\pm5$ km s$^{-1}$ followed by a steeper increase up to $σ_{v, z}$ $\sim 80$ km s$^{-1}$ for SFR $\gtrsim 1$ M$_\odot$ yr$^{-1}$. This is consistent with recent theoretical models that suggest a $σ_{v, z}$ floor driven by star-formation feedback processes with an upturn in $σ_{v, z}$ at higher SFR driven by gravitational transport of gas through the disc.

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Mathew R. Varidel, Scott M. Croom, Geraint F. Lewis, Deanne B. Fisher, Karl Glazebrook, Barbara Catinella, Luca Cortese, Mark R. Krumholz, Joss Bland-Hawthorn, Julia J. Bryant, Brent Groves, Sarah Brough, Christoph Federrath, Jon S. Lawrence, Nuria P. Lorente, Matt S. Owers, Samuel N. Richards, Ángel R. López-Sánchez, Sarah M. Sweet, Jesse van de Sande, Sam P. Vaughan. 2020-05-18. The SAMI Galaxy Survey: Gas velocity dispersions in low-$z$ star-forming galaxies and the drivers of turbulence. https://doi.org/10.1093/mnras%2Fstaa1272

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