Mapping the Clumpy Structures within Submillimeter Galaxies using
  Laser-Guide Star Adaptive Optics Spectroscopy
  We present the first integral-field spectroscopic observations of
high-redshift submillimeter-selected galaxies (SMGs) using Laser Guide Star
Adaptive Optics (LGS-AO). We target H-alpha emission of three SMGs at redshifts
z~1.4-2.4 with the OH-Suppressing Infrared Imaging Spectrograph (OSIRIS) on
Keck. The spatially-resolved spectroscopy of these galaxies reveals unresolved
broad H-alpha line regions (FWHM>1000 km/s) likely associated with an AGN and
regions of diffuse star formation traced by narrow-line H-alpha emission
(FWHM<500 km/s) dominated by multiple Halpha-bright stellar clumps, each
contributing 1-30% of the total clump-integrated H-alpha emission. We find that
these SMGs host high star-formation rate surface densities, similar to local
extreme sources, such as circumnuclear starbursts and luminous infrared
galaxies. However, in contrast to these local environments, SMGs appear to be
undergoing such intense activity on significantly larger spatial scales as
revealed by extended H-alpha emission over 4-16 kpc. H-alpha kinematics show no
evidence of ordered global motion as would be found in a disk, but rather large
velocity offsets (~few x 100 km/s) between the distinct stellar clumps.
Together with the asymmetric distribution of the stellar clumps around the AGN
in these objects, it is unlikely that we are unveiling a clumpy disk structure
as has been suggested in other high-redshift populations of star-forming
galaxies. The SMG clumps in this sample may correspond to remnants of
originally independent gas-rich systems that are in the process of merging,
hence triggering the ultraluminous SMG phase.
