The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7

E. Wisnioski, N. M. Förster Schreiber, S. Wuyts, E. Wuyts, K. Bandara, D. Wilman, R. Genzel, R. Bender, R. Davies, M. Fossati, P. Lang, J. T. Mendel, A. Beifiori, G. Brammer, J. Chan, M. Fabricius, Y. Fudamoto, S. Kulkarni, J. Kurk, D. Lutz, E. J. Nelson, I. Momcheva, D. Rosario, R. Saglia, S. Seitz, L. J. Tacconi, P. G. van Dokkum

Published 2014-09-24Version 1

We present the KMOS^3D survey, a new integral field survey of over 600 galaxies at 0.7<z<2.7 using KMOS at the Very Large Telescope (VLT). The KMOS^3D survey utilizes synergies with multi-wavelength ground and space-based surveys to trace the evolution of spatially-resolved kinematics and star formation from a homogeneous sample over 5 Gyrs of cosmic history. Targets, drawn from a mass-selected parent sample from the 3D-HST survey, cover the star formation-stellar mass ($M_*$) and rest-frame $(U-V)-M_*$ planes uniformly. We describe the selection of targets, the observations, and the data reduction. In the first year of data we detect Halpha emission in 191 $M_*=3\times10^{9}-7\times10^{11}$ Msun galaxies at z=0.7-1.1 and z=1.9-2.7. In the current sample 83% of the resolved galaxies are rotation-dominated, determined from a continuous velocity gradient and $v_{rot}/\sigma>1$, implying that the star-forming 'main sequence' (MS) is primarily composed of rotating galaxies at both redshift regimes. When considering additional stricter criteria, the Halpha kinematic maps indicate at least ~70% of the resolved galaxies are disk-like systems. Our high-quality KMOS data confirm the elevated velocity dispersions reported in previous IFS studies at z>0.7. For rotation-dominated disks, the average intrinsic velocity dispersion decreases by a factor of two from 50 km/s at z~2.3 to 25 km/s at z~0.9 while the rotational velocities at the two redshifts are comparable. Combined with existing results spanning z~0-3, disk velocity dispersions follow an approximate (1+z) evolution that is consistent with the dependence of velocity dispersion on gas fractions predicted by marginally-stable disk theory.