DYNAMO II: Coupled Stellar and Ionized Gas Kinematics in Two Low
  Redshift Clumpy Disks
  We study the spatially resolved stellar kinematics of two star-forming
galaxies at z = 0.1 from the larger DYnamics of Newly Assembled Massive Objects
(DYNAMO) sample. These galaxies, which have been characterized by high levels
of star formation and large ionized gas velocity dispersions, are considered
possible analogs to high-redshift clumpy disks. They were observed using the
GMOS instrument in integral field spectroscopy (IFS) mode at the Gemini
Observatory with high spectral resolution (R=5400, equivalent to 24 km/s at the
observed wavelengths) and 6 hour exposure times in order to measure the
resolved stellar kinematics via absorption lines. We also obtain higher-quality
emission line kinematics than previous observations. The spatial resolution
(1.2 kpc) is sufficient to show that the ionized gas in these galaxies (as
traced by H-beta emission) is morphologically irregular, forming multiple giant
clumps while stellar continuum light is smooth and well described by an
exponential profile. Clumpy gas morphologies observed in IFS data are confirmed
by complementary narrow band H-alpha imaging from the Hubble Space Telescope.
Morphological differences between the stars and ionized gas are not reflected
dynamically as stellar kinematics are found the be closely coupled to the
kinematics of the ionized gas: both components are smoothly rotating with large
velocity dispersions (~40 km/s) suggesting that the high gas dispersions are
not primarily driven by star-formation feedback. In addition, the stellar
population ages of these galaxies are estimated to be quite young (60-500 Myr).
The large velocity dispersions measured for these young stars suggest that we
are seeing the formation of thick disks and/or stellar bulges in support of
recent models which produce these from clumpy galaxies at high redshift.
