The SAMI Galaxy Survey: energy sources of the turbulent velocity dispersion in spatially resolved local star-forming galaxies

Luwenjia Zhou, Christoph Federrath, Tiantian Yuan, Fuyan Bian, Anne M. Medling, Yong Shi, Joss Bland-Hawthorn, Julia J. Bryant, Sarah Brough, Barbara Catinella, Scott M. Croom, Michael Goodwin, Gregory Goldstein, Andrew W. Green, Iraklis S. Konstantopoulos, Jon S. Lawrence, Matt S. Owers, Samuel N. Richards, Sebastian F. Sanchez

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Abstract

We investigate the energy sources of random turbulent motions of ionized gas from H alpha emission in eight local star-forming galaxies from the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. These galaxies satisfy strict pure star-forming selection criteria to avoid contamination from active galactic nuclei (AGNs) or strong shocks/outflows. Using the relatively high spatial and spectral resolution of SAMI, we find that - on sub-kpc scales, our galaxies display a flat distribution of ionized gas velocity dispersion as a function of star formation rate (SFR) surface density. A major fraction of our SAMI galaxies shows higher velocity dispersion than predictions by feedback-driven models, especially at the low SFR surface density end. Our results suggest that additional sources beyond star formation feedback contribute to driving random motions of the interstellar medium in star-forming galaxies. We speculate that gravity, galactic shear and/or magnetorotational instability may be additional driving sources of turbulence in these galaxies.

Original languageEnglish
Pages (from-to)4573-4582
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume470
Issue number4
DOIs
Publication statusPublished - Oct 2017

Cite this

Zhou, L., Federrath, C., Yuan, T., Bian, F., Medling, A. M., Shi, Y., Bland-Hawthorn, J., Bryant, J. J., Brough, S., Catinella, B., Croom, S. M., Goodwin, M., Goldstein, G., Green, A. W., Konstantopoulos, I. S., Lawrence, J. S., Owers, M. S., Richards, S. N., & Sanchez, S. F. (2017). The SAMI Galaxy Survey: energy sources of the turbulent velocity dispersion in spatially resolved local star-forming galaxies. Monthly Notices of the Royal Astronomical Society, 470(4), 4573-4582. https://doi.org/10.1093/mnras/stx1504