Intense Star Formation and Feedback at High Redshift: Spatially Resolved Properties of thez= 2.6 Submillimeter Galaxy SMM J14011+0252

We present a detailed analysis of the spatially-resolved properties of thelensed submillimeter galaxy SMMJ14011+0252 at z=2.56, combining deepnear-infrared integral-field data obtained with SPIFFI on the VLT with othermulti-wavelength data sets. The broad characteristics of SMMJ14011+0252 are inagreement with what is expected for the early evolution of local massivespheroidal galaxies. From continuum and line flux, velocity, and dispersionmaps, we measure the kinematics, star-formation rates, gas densities, andextinction for individual subcomponents. The star formation intensity issimilar to low-redshift ``maximal starbursts'', while the line fluxes and thedynamics of the emission line gas provide direct evidence for astarburst-driven wind with physical properties very similar to localsuperwinds. We also find circumstantial evidence for "self-regulated" starformation within J1. The relative velocity of the bluer companion J2 yields adynamical mass estimate for J1 within about 20 kpc, M_dyn \sim 1\times 10^{11}M_sun. The relative metallicity of J2 is 0.4 dex lower than in J1n/s,suggesting different star formation histories. SED fitting of the continuumpeak J1c confirms and substantiates previous suggestions that this component isa z=0.25 interloper. When removing J1c, the stellar continuum and H-alpha lineemission appear well aligned spatially in two individual components J1n andJ1s, and coincide with two kinematically distinct regions in the velocity map,which might well indicate a merging system. This highlights the closesimilarity between SMGs and ULIRGs, which are often merger-driven maximalstarbursts, and suggests that the intrinsic mechanisms of star-formation andrelated feedback are similar to low-redshift strongly star-forming systems.