  We present spectropolarimetric measurements of dark-cored penumbral filaments
taken with Hinode at a resolution of 0.3". Our observations demonstrate that
dark-cored filaments are more prominent in polarized light than in continuum
intensity. Far from disk center, the Stokes profiles emerging from these
structures are very asymmetric and show evidence for magnetic fields of
different inclinations along the line of sight, together with strong Evershed
flows of at least 6-7 km/s. In sunspots closer to disk center, dark-cored
penumbral filaments exhibit regular Stokes profiles with little asymmetries due
to the vanishing line-of-sight component of the horizontal Evershed flow. An
inversion of the observed spectra indicates that the magnetic field is weaker
and more inclined in the dark cores as compared with the surrounding bright
structures. This is compatible with the idea that dark-cored filaments are the
manifestation of flux tubes carrying hot Evershed flows.
