The misdirected central engine of the hyperluminous infrared galaxy and type 2 QSO IRAS P09104+4109

Hubble Space Telescope Wide-Field Planetary Camera 2 imaging polarimetry of the hyperluminous infrared galaxy (and misdirected QSO) IRAS P09104+4109 r eveals a highly polarized (p approximate to 20%) giant (similar to 5 kpc) b ipolar reflection nebula centered on the nucleus. This, together with our p revious detection of broad, polarized Mg II and newly detected broad, polar ized Palmer emission lines in our ground-based spectropolarimetry, confirms that the lobes of the nebula are dominated by scattered light from the mis directed QSO and that the object would be indistinguishable from typical lu minous QSOs if viewed from either pole. Comparison with previously publishe d narrowband images in the light of [O III] lambda lambda 4959, 5007 and [O - II] lambda 3727 shows that the northern lobe of the nebula is coincident with the ionization cone, thus the same light that impinges on the scatteri ng material also ionizes the narrow-line gas. The biconical structure and h igh polarization suggest that the central UV continuum source is surrounded by a dusty torus of half-opening angle similar to 23 degrees inclined simi lar to 37 degrees with respect to our line of sight. The radio structure of this radio-intermediate object also indicates a long-lived axisymmetry to the central power source, but with a different axis relative to the scatter ing bicone. We propose that this difference in axes betrays the history of a cataclysmic event that altered the fundamental orientation of the central engine-the bicone defines the current axis of the system. Radio-emitting p lasma is beginning to move outward along this new axis, depriving the old r adio lobes of power. IRAS P09104+4109 is the first radio-quiet/intermediate object of QSO luminosity and hidden broad lines to show direct evidence th at the axisymmetric torus inferred to exist in many Seyfert nuclei is also present in objects of high luminosity.