SPATIALLY RESOLVED SPECTROSCOPY OF SUBMILLIMETER GALAXIES AT z ≃ 2

We present near-infrared integral-field spectroscopic observations targeting H alpha in eight submillimeter galaxies (SMGs) at z = 1.3-2.5 using the Very Large Telescope/Spectrograph for Integral Field Observations in the Near Infrared, obtaining significant detections for six of them. The star formation rates derived from the H alpha emission are similar to 100 M-circle dot yr(-1), which account for only similar to 20%-30% of the infrared-derived values, thus suggesting that these systems are very dusty. Two of these systems present [N II]/H alpha ratios indicative of the presence of an active galactic nucleus. We mapped the spatial distribution and kinematics of the star-forming regions in these galaxies on. kiloparsec. scales. In general, the H alpha morphologies tend to be highly irregular and/or clumpy, showing spatial extents of similar to 3-11. kpc. We find evidence for significant spatial offsets, of similar to 0 '',1-0 ''.4 or 1.2-3.4 kpc, between the H alpha and the continuum emission in three of the sources. Performing a kinemetry analysis,. we conclude that the majority of the sample is not consistent with disk-like rotation-dominated kinematics. Instead, they tend to show irregular and/or clumpy and turbulent velocity and velocity dispersion fields. This can be interpreted as evidence for a. scenario in which these extreme star formation episodes are triggered by galaxy-galaxy interactions and major mergers. In contrast to recent results for SMGs, these sources appear to follow the same relations between gas and star-forming rate densities as less luminous and/or normal star-forming galaxies.