We present adaptive optics assisted , spatially resolved spectroscopy of a sample of nine H \alpha -selected galaxies at z = 0.84–2.23 drawn from the HiZELS narrow-band survey .
These galaxies have star-formation rates of 1–27 M _ { \odot } yr ^ { -1 } and are therefore representative of the typical high-redshift star-forming population .
Our \sim kpc-scale resolution observations show that approximately half of the sample have dynamics suggesting that the ionised gas is in large , rotating disks .
We model their velocity fields to infer the inclination-corrected , asymptotic rotational velocities .
We use the absolute B -band magnitudes and stellar masses to investigate the evolution of the B -band and stellar mass Tully-Fisher relationships .
By combining our sample with a number of similar measurements from the literature , we show that , at fixed circular velocity , the stellar mass of star-forming galaxies has increased by a factor 2.5 between z = 2 and z = 0 , whilst the rest-frame B -band luminosity has decreased by a factor \sim 6 over the same period .
Together , these demonstrate a change in mass-to-light ratio in the B -band of \Delta ( M / L _ { B } ) / ( M / L _ { B } ) _ { z = 0 } \sim 3.5 between z = 1.5 and z = 0 , with most of the evolution occuring below z = 1 .
We also use the spatial variation of [ N ii ] / H \alpha to show that the metallicity of the ionised gas in these galaxies declines monotonically with galactocentric radius , with an average \Delta log ( O / H ) / \Delta R = - 0.027 \pm 0.005 dex kpc ^ { -1 } .
This gradient is consistent with predictions for high-redshift disk galaxies from cosmologically based hydrodynamic simulations .