We report the analysis of near-infrared imaging , polarimetric and spectroscopic observations of the powerful radio galaxy 3C 433 ( z = 0.1016 ) , obtained with the HST and UKIRT telescopes .
The high spatial resolution of HST allows us to study the near-nuclear regions of the galaxy ( < 1 kpc ) .
In line with previous observations , we find that 3C 433 has an unresolved core source that is detected in all near-IR bands , but dominates over the host galaxy emission at 2.05 \mu m .

Our analysis reveals : ( 1 ) the presence of a dust lane aligned close to perpendicular ( PA = 70 \pm 5 \degr ) to the inner radio jet axis ( PA = -12 \pm 2 \degr ) ; ( 2 ) a steep slope to the near-IR SED ( \alpha = 5.8 \pm 0.1 ; F _ { \nu } \propto \nu ^ { - \alpha } ) ; ( 3 ) an apparent lack of broad permitted emission lines at near-IR wavelengths , in particular the absence of a broad Pa \alpha emission line ; and ( 4 ) high intrinsic polarization for the unresolved core nuclear source ( 8.6 \pm 1 per cent ) , with an E-vector perpendicular ( PA= 83.0 \pm 2.3 \degr ) to the inner radio jet .
Using five independent techniques we determine an extinction to the compact core source in the range 3 < A _ { V } < 67 mag .

An analysis of the long wavelength SED rules out a synchrotron origin for the high near-IR polarization of the compact core source .
Therefore , scattering and dichroic extinction are plausible polarizing mechanisms , although in both of these cases the broad permitted lines from the AGN are required to have a width > 10 ^ { 4 } km s ^ { -1 } ( FWHM ) to escape detection in our near-IR spectrum .
Dichroic extinction is the most likely polarization mechanism because it is consistent with the various available extinction estimates .
In this case , a highly ordered , coherent toroidal magnetic field must be present in the obscuring structure close to the nucleus .