Shocked Superwinds from the z ~ 2 Clumpy Star-forming Galaxy, ZC406690

We have obtained high-resolution data of the z � 2 ring-like, clumpy star-forming galaxy (SFG) ZC406690 using the VLT/SINFONI with AO (in K-band) and in seeing-limited mode (in H- and J-band). Our data includes all of the main strong optical emission lines: [OII], [OIII], Hα, Hβ, [NII], and [SII]. We find broad, blueshifted Hα and [OIII] emission line wings in the spectra of the galaxy’s massive, star-forming clumps (σ � 85 km s −1 ) and even broader wings (up to 70% of the total Hα flux, with σ � 290 km s −1 ) in regions spatially offset from the clumps by � 2 kpc. The broad emission likely originates from large-scale outflows with mass outflow rates from individual clumps that are 1–8x the SFR of the clumps. Based on emission line ratio diagnostics ([NII]/Hα and [SII]/Hα) and photoionization and shock models, we find that the emission from the clumps is due to a combination of photoionization from the star-forming regions and shocks generated in the outflowing component, with 5–30% of the emission deriving from shocks. In terms of the ionization parameter (6x10 7 -10 8 cm/s, based on both the SFR and the O32 ratio), density (local electron densities of 300–1800 cm −3 in and around the clumps, and ionized gas column densities of 1200–8000 M⊙/pc 2 ), and SFR (10–40 M⊙ yr −1 ), these clumps more closely resemble nuclear starburst regions of local ULIRGs and dwarf irregulars than HII regions in local galaxies. However, the star-forming clumps are not located in the nucleus as in local starburst galaxies but instead are situated in a ring several kpc from the center of their high-redshift host galaxy, and have an overall disk-like morphology. The two brightest clumps are quite different in terms of their internal properties, energetics and relative ages, and thus we are given a glimpse at two different stages in the formation and evolution of rapidly star-forming giant clumps at high-z. Subject headings: galaxies: high redshift – galaxies: evolution – galaxies: emission lines – galaxies: star formation – ISM: jets and outflows