The Binary Black Hole Model for Mrk 231 Bites the Dust
  Mrk 231 is a nearby quasar with an unusually red near-UV-to-optical
continuum, generally explained as heavy reddening by dust (e.g., Leighly et al.
2014). Yan et al. 2015 proposed that Mrk~231 is a milli-parsec black-hole
binary with little intrinsic reddening. We show that if the observed FUV
continuum is intrinsic, as assumed by Yan et al. 2015, it fails by a factor of
about 100 in powering the observed strength of the near-infrared emission
lines, and the thermal near and mid-infrared continuum. In contrast, the line
and continuum strengths are typical for a reddened AGN spectral energy
distribution. We find that the HeI*/Pbeta ratio is sensitive to the spectral
energy distribution for a one-zone model. If this sensitivity is maintained in
general broad-line region models, then this ratio may prove a useful diagnostic
for heavily reddened quasars. Analysis of archival HST STIS and FOC data
revealed evidence that the far-UV continuum emission is resolved on size scales
of ~40 parsecs. The lack of broad absorption lines in the far-UV continuum
might be explained if it were not coincident with the central engine. One
possibility is that it is the central engine continuum reflected from the
receding wind on the far side of the quasar.
