GOALS-JWST: The Warm Molecular Outflows of the Merging Starburst Galaxy NGC 3256

We present James Webb Space Telescope (JWST) Integral Field Spectrograph observations of NGC 3256, a local infrared-luminous late-stage merging system with two nuclei about 1 kpc apart, both of which have evidence of cold molecular outflows. Using JWST NIRSpec and MIRI datasets, we investigate this morphologically complex system on spatial scales of <100 pc, where we focus on the warm molecular H_2 gas surrounding the nuclei. We detect collimated outflowing warm H_2 gas originating from the southern nucleus, though we do not find significant outflowing warm H_2 gas surrounding the northern nucleus. Within the observed region, the maximum intrinsic velocities of the outflow reach up to ∼1,000 km s^-1, and extend out to a distance of 0.7 kpc. Based on H_2 S(7)/S(1) line ratios, we find a larger fraction of warmer gas near the S nucleus, which decreases with increasing distance from the nucleus, signifying the S nucleus as a primary source of H_2 heating. The gas mass of the warm H_2 outflow component is estimated to be M_warm,out = 8.9×10^5 M_⊙, as much as 4% of the cold H_2 mass as estimated using ALMA CO data. The outflow time scale is about 7×10^5 yr, resulting in a mass outflow rate of Ṁ_warm,out = 1.3 M_⊙ yr^-1 and kinetic power of P_warm,out ∼ 2×10^41 erg s^-1. Lastly, the regions where the outflowing gas reside show high [FeII]/Paβ and H_2/Brγ line ratios, indicating enhanced mechanical heating caused by the outflows. At the same time, the 3.3 μm and 6.2 μm Polycyclic Aromatic Hydrocarbon fluxes in these regions are not significantly suppressed compared to those outside the outflows, suggesting the outflows have no clear negative feedback effect on the local star formation.