K ^- nuclear potentials based on chiral meson-baryon amplitudes

K ^- nuclear optical potentials are constructed from in-medium subthreshold K̄N scattering amplitudes within a chirally motivated coupled-channel model. We demonstrate how the strong energy and density dependence of the scattering amplitudes at and below threshold leads to a deep K ^- nuclear potential V _K ^- for kaonic atoms and K ^- nuclear quasibound states. Selfconsistent evaluations yield K ^- potential depths -ReV _K ^- (ρ ₀) of order 100 MeV. Allowing for K ^- NN absorption, better agreement with K ^- atoms data is achieved, leading to increased potential depths, -ReV _K ^- (ρ ₀) ∼ 175 MeV, in accord with density dependent potentials obtained in purely phenomenological fits. Self consistent dynamical calculations of K ^- nuclear quasibound states are reported and discussed, as well.