An anomalous ultraviolet extension in NGC 6251

Deep U-band Faint Object Camera (FOC) images of the nuclear region of NGC 6251 have revealed a region of extended emission that is most probably radiation scattered from a continuum source in the nucleus. This radiation lies interior to a dust ring, is nearly perpendicular to the radio jet axis, and is seen primarily in the FOC U and B filters. The extension has a low observed polarization (less than or equal to 10%) and is unlikely to arise from line emission. We know of no other examples similar to what we have found in NGC 6251, and we offer some tentative explanations. The nuclear morphology shows clear similarities to that seen in the nucleus of NGC 4261, except for the extended U-band radiation.