Falling Outer Rotation Curves of Star-forming Galaxies at 0.6 less than or similar to z less than or similar to 2.6 Probed with KMOS3D and SINS/zC-SINF

We exploit the deep, resolved, Ha kinematic data from the KMOS3D and SINS/zC-SINF surveys to examine the largely unexplored outer-disk kinematics of star-forming galaxies ( SFGs), out to the peak of cosmic star formation. Our sample contains 101 SFGs, representative of the more massive ( 9.3 = 0.05), in combination with a sizeable level of pressure support in the outer disk. These findings agree with recent studies demonstrating that high-zstar- forming disks are strongly baryon-dominated within the disk scale, and furthermore suggest that pressure gradients caused by large, turbulent gas motions are present even in their outer disks. These results are largely independent of our model assumptions, such as the presence of stellar bulges, the effect of adiabatic contraction, and variations in halo concentration.