Yu, XiaolingBian, FuyanKrumholz, MarkShi, YongLi, SonglinChen, Jianhang2023-03-302023-03-300035-8711http://hdl.handle.net/1885/287878Two competing models, gravitational instability-driven transport and stellar feedback, have been proposed to interpret the high velocity dispersions observed in high-redshift galaxies. We study the major mechanisms to drive the turbulence in star-forming galaxies using a sample of galaxies from the xCOLD GASS survey, selected based on their star formation rate (SFR) and gas fraction to be in the regime that can best distinguish between the proposed models. We perform Wide Field Spectrograph integral field spectroscopic observations to measure the intrinsic gas velocity dispersions, circular velocities, and orbital periods in these galaxies. Comparing the relation between the SFR, velocity dispersion, and gas fraction with predictions of these two theoretical models, we find that our results are most consistent with a model that includes both transport and feedback as drivers of turbulence in the interstellar medium. By contrast, a model where stellar feedback alone drives turbulence under-predicts the observed velocity dispersion in our galaxies, and does not reproduce the observed trend with gas fraction. These observations therefore support the idea that gravitational instability makes a substantial contribution to turbulence in high-redshift and high-SFR galaxies.XY and YS acknowledge the support from the National Key R&D Program of China (No. 2017YFA0402704, No. 2018YFA0404502), the National Natural Science Foundation of China (NSFC grants 11825302, 11733002, and 11773013). MRK acknowledges function from the Australian Research Council through its Discovery Projects and Future Fellowship schemes (awards DP190101258 and FT180100375). FB acknowledges support from the Australian Research Council through Discovery Projects (award DP190100252) and Chinese Academy of Sciences (CAS) through a China-Chile Joint Research Fund (CCJRF1809) administered by the CAS South America Center for Astronomy (CASSACA).application/pdfen-AU© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Societygalaxies: ISMgalaxies: star formationgalaxies: kinematics and dynamics202110.1093/mnras/stab16812022-01-16