  The Mrk 463 system is known to host two powerful sources separated by about 4
kpc, both identified as active galactic nuclei (AGN). This makes the Mrk 463
system a unique laboratory to study the geometry and dynamics of galaxy merging
and its relation to AGN duty cycles. The eastern nuclei, Mrk 463E, is the
brightest of the two and thus a prime target for a polarimetric study. It is
classified as a Seyfert 2 galaxy, meaning that one could expect large
polarization degrees from scattering off electrons and dust in the polar winds.
In the continuity of our series of papers, we reduced archived and previously
unpublished polarization observations obtained with the Faint Object Camera
(FOC) onboard the Hubble Space Telescope (HST), to obtain a high resolution
near ultraviolet (near-UV) polarization map of the Mrk 463E nuclei. We coupled
this map to near infrared (NIR) and X-ray observations to get a clear picture
of the geometric arrangement of matter around the core of Mrk 463E. We found
that the nucleus location is further South from the optical peak flux than
previously estimated. The strongly polarized conical wind has a half-opening
angle of ~15{\deg} and display three main periods of mass ejection. Its
polarization allowed us to estimate the AGN inclination towards the observer
(~55{\deg}) Finally, our maps revealed a gas streamer connecting Mrk 463E and
Mrk 463W, with a tentative detection of a large kpc-scale ordered magnetic
field connecting both galaxies. This unpublished observation turned out to
offer more than the original proposal asked for and allowed to derive tight
geometric and dynamical constraints for Mrk 463E. High resolution radio maps
and IR polarimetry are now necessary to further study the jet and the newly
discovered gas streamer.
