Hubble Space Telescope ultraviolet spectroscopy of the highly polarized but quiescent quasar OI 287

The quasar OI 287 has a unique combination of properties, including a high and constant optical polarization oriented parallel to the radio axis, a quiescent optical flux, and a lobe-dominant radio source. Previous studies have led to the picture of an edge-on thin dusty torus occulting a featureless continuum (FC) source and a broad line region (BLR) in this object. The FC source and the BLR are seen only in reflected (polarized) light. In the unified models, this makes OI 287 a 'quasar 2', analogous to the type 2 Seyfert galaxies and the narrow-line radio galaxies. Our UV spectrum adds two bits of information consistent with the above ideas. First, the spectrum neither turns up in the UV, as expected for optically thin dust scattering, nor turns down as expected for polarization by dust transmission. It is consistent with reflection by free electrons or optically thick dust. Second, there are in fact blueshifted absorption troughs associated with the C IV 1549 A line, supporting the analogy with BALs, as well as the idea that the BALs are objects which present a nearly edge-on view of a disk structure.