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

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Zhou, Luwenjia, Federrath, Christoph, Yuan, Tiantian, Bian, Fuyan, Medling, Anne M., Shi, Yong, Bland-Hawthorn, Joss, Bryant, Julia J., Brough, Sarah, Catinella, Barbara, Croom, Scott M., Goodwin, Michael, Goldstein, Gregory, Green, Andrew W., Konstantopoulos, Iraklis S., Lawrence, Jon S., Owers, Matt S., Richards, Samuel N., Sanchez, Sebastian F.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Royal Astronomical Society 2017
• Subjects: ISM: kinematics and dynamics; galaxies: ISM; galaxies: star formation; Hubble; sami
• Online Access: https://doi.org/10.1093/mnras/stx1504

We investigate the energy sources of random turbulent motions of ionized gas from H α 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. © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Received: 18 March 2017. Revision Received: 13 June 2017. Accepted: 14 June 2017. Published: 20 June 2017. LZ and YS acknowledge support for this work from the National Natural Science Foundation of China (NSFC grant 11373021) and the Excellent Youth Foundation of the Jiangsu Scientific Committee (grant BK20150014). CF gratefully acknowledges funding provided by the Australian Research Council's Discovery Projects (grants DP150104329 and DP170100603). Support for AMM is provided by NASA through Hubble Fellowship grant no. HST-HF2-51377 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. for NASA, under contract NAS5-26555. We thank R. Genzel, N. Förster Schreiber, M.D. Lehnert and N.P.H. Nesvadba for their support on providing high-z measurements displayed in this ...