IROCKS: SPATIALLY RESOLVED KINEMATICS OF z. ∼ 1 STAR-FORMING GALAXIES

We present results from the Intermediate Redshift OSIRIS Chemo-Kinematic Survey (IROCKS) for sixteen z similar to 1 and one z similar to 1.4 star-forming galaxies. All galaxies were observed with OSIRIS with the laser guide star adaptive optics system at Keck Observatory. We use rest-frame nebular H alpha emission lines to trace morphologies and kinematics of ionized gas in star-forming galaxies on sub-kiloparsec physical scales. We observe elevated velocity dispersions (sigma greater than or similar to. 50 km s(-1)) seen in z > 1.5 galaxies persist at z similar to 1 in the integrated galaxies. Using an inclined disk model and the ratio of v/sigma, we find that 1/3 of the z similar to 1 sample are disk candidates while the other 2/3 of the sample are dominated by merger-like and irregular sources. We find that including extra attenuation toward H II regions derived from stellar population synthesis modeling brings star formation rates (SFRs) using Ha and stellar population fit into a better agreement. We explore the properties of the compact Ha sub-component, or "clump," at z similar to 1 and find that they follow a similar size-luminosity relation as local H II regions but are scaled-up by an order of magnitude with higher luminosities and sizes. Comparing the z similar to 1 clumps to other high-redshift clump studies, we determine that the clump SFR surface density evolves as a function of redshift. This suggests clump formation is directly related to the gas fraction in these systems and may support disk fragmentation as their formation mechanism since gas fraction scales with redshift.