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

    Research output: Contribution to journalArticlepeer-review

    39 Citations (Scopus)

    Abstract

    We investigate the energy sources of random turbulent motions of ionized gas from Ha 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

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