We present first results from the KMOS Ultra-deep Rotation Velocity Survey(KURVS), aimed at studying the outer rotation curves shape and dark mattercontent of 22 star-forming galaxies at $z\sim1.5$. These galaxies represent`typical' star-forming discs at $z \sim 1.5$, being located within thestar-forming main sequence and stellar mass-size relation with stellar masses$9.5\leqslant$log$(M_{\star}/\mathrm{M_{\odot}})\leqslant11.5$. We extractindividual rotation curves out to 4 times the effective radius, on average, or$\sim 10-15$ kpc. Most rotation curves are flat or rising between three- andsix-disc scale radii. Only three objects with dispersion-dominated dynamics($v_{\rm rot}/\sigma_0\sim0.2$) have declining outer rotation curves at morethan 5$\sigma$ significance. After accounting for seeing and pressure support,the nine rotation-dominated discs with $v_{\rm rot}/\sigma_0\geqslant1.5$ haveaverage dark matter fractions of $50 \pm 20\%$ at the effective radius, similarto local discs. Together with previous observations of star-forming galaxies atcosmic noon, our measurements suggest a trend of declining dark matter fractionwith increasing stellar mass and stellar mass surface density at the effectiveradius. Simulated EAGLE galaxies are in quantitative agreement withobservations up to log$(M_{\star}R_{\rm eff}^{-2}/\mathrm{M_{\odot}kpc^{-2}})\sim 9.2$, and over-predict the dark matter fraction of galaxies with highermass surface densities by a factor of $\sim 3$. We conclude that the dynamicsof typical rotationally-supported discs at $z \sim 1.5$ is dominated by darkmatter from effective radius scales, in broad agreement with cosmologicalmodels. The tension with observations at high stellar mass surface densitysuggests that the prescriptions for baryonic processes occurring in the mostmassive galaxies (such as bulge growth and quenching) need to be reassessed.

We report high-quality H${\alpha}$/CO, imaging spectroscopy of nine massive(log median stellar mass = 10.65 $M_{\odot}$), disk galaxies on thestar-forming, main sequence (henceforth `SFGs'), near the peak of cosmic galaxyevolution ($z\sim$1.1-2.5), taken with the ESO-Very Large Telescope, IRAM-NOEMAand Atacama Large Millimeter/submillimeter Array. We fit the major axisposition-velocity cuts with beam-convolved, forward models with a bulge, aturbulent rotating disk, and a dark matter (DM) halo. We include priors forstellar and molecular gas masses, optical light effective radii andinclinations, and DM masses from our previous rotation curve analyses of thesegalaxies. We then subtract the inferred 2D model-galaxy velocity and velocitydispersion maps from those of the observed galaxies. We investigate whether theresidual velocity and velocity dispersion maps show indications for radialflows. We also carry out kinemetry, a model-independent tool for detectingradial flows. We find that all nine galaxies exhibit significant non-tangentialflows. In six SFGs, the inflow velocities ($v_r\sim$30-90 km s$^{-1}$, 10%-30%of the rotational component) are along the minor axis of these galaxies. In twocases the inflow appears to be off the minor axis. The magnitudes of the radialmotions are in broad agreement with the expectations from analytic models ofgravitationally unstable, gas-rich disks. Gravitational torques due to clumpand bar formation, or spiral arms, drive gas rapidly inward and result in theformation of central disks and large bulges. If this interpretation is correct,our observations imply that gas is transported into the central regions on ~10dynamical time scales.