2007ApJ...658...78W

We present 0.1" resolution near-infrared integral field spectroscopy of Hα in a z=1.4781 star-forming galaxy, Q2343-BM133. These observations were obtained with the OH Suppressing Infra-Red Imaging Spectrograph (OSIRIS) using the W. M. Keck Observatory laser guide star adaptive optics (LGS AO) system. Hα emission is resolved over a 0.8''(6.8 kpc)x0.5''(4.3 kpc) region with a 0.1" spatial resolution. We find a global flux of 4.2±0.6x10^–16 ergs/s/cm2, and detect a spatially resolved velocity gradient of ∼134 km/s across the galaxy and a global velocity dispersion of 73±9 km/s. An upper limit of [N II]/Hα≲0.12 is inferred, which implies that this galaxy is not dominated by an active galactic nucleus and has a metallicity at or below 1/2 solar metallicity. We derive a star formation rate (SFR) of 47±6 M_☉/yr and a dereddened SFR of 66±9 M_☉/yr. Two-dimensional kinematics for Q2343-BM133 fit well with an inclined disk model, with which we estimate an enclosed mass of 4.3x10⁹ M_☉ within 5.5 kpc. A possible merger scenario is also presented, and cannot be fully ruled out. We derive a virial mass of 1.1x10¹⁰ M_☉for a disk geometry, using the observed velocity dispersion. We propose that Q2343-BM133 is currently at an early stage of disk formation at a look-back time of 9.3 Gyr.