2017ApJ...839...57S

Using observations made with MOSFIRE on Keck I as part of the ZFIRE survey, we present the stellar mass Tully-Fisher relation at 2.0 z 2.5. The sample was drawn from a stellar-mass-limited, K_s-band-selected catalog from ZFOURGE over the CANDELS area in the COSMOS field. We model the shear of the Hα emission line to derive rotational velocities at 2.2×the scale radius of an exponential disk (V_2.2). We correct for the blurring effect of a 2D point-spread function (PSF) and the fact that the MOSFIRE PSF is better approximated by a Moffat than a Gaussian, which is more typically assumed for natural seeing. We find for the Tully-Fisher relation at 2.0 z 2.5 that logV_2.2=(2.18±0.051)+(0.193 ± 0.108)(logM/M_☉-10) and infer an evolution of the zero-point of ΔM/M_☉=-0.25±0.16 dex or ΔM/M_☉=-0.39±0.21 dex compared to z = 0 when adopting a fixed slope of 0.29 or 1/4.5, respectively. We also derive the alternative kinematic estimator S_0.5, with a best-fit relation logS_0.5=(2.06±0.032) +(0.211±0.086)(logM/M_☉-10), and infer an evolution of ΔM/M_☉ =-0.45±0.13 dex compared to z 1.2 if we adopt a fixed slope. We investigate and review various systematics, such as PSF effects, projection effects, systematics related to stellar mass derivation, selection biases, and slope. We find that discrepancies between the various literature values are reduced when taking these into account. Our observations correspond well with the gradual evolution predicted by semianalytic models.