The host galaxy of OJ 287 revealed by optical and near-infrared imaging
  The BL Lacertae object OJ 287 (z = 0.306) has unique double-peaked optical
outbursts every ~12 years, and it presents one of the best cases for a
small-separation binary supermassive black hole (SMBH) system, with an
extremely massive primary log (M_BH/M_Sun) ~ 10.3. However, the host galaxy is
unresolved or only marginally detected in all optical studies so far,
indicating a large deviation from the bulge mass - SMBH mass relation. We have
obtained deep, high spatial resolution i-band and K-band images of OJ~287 when
the target was in a low state, which enable us to detect the host galaxy. We
find the broad-band photometry of the host to be consistent with an early type
galaxy with M_R = -22.5 and M_K = -25.2, placing it in the middle of the host
galaxy luminosity distribution of BL Lacertae objects. The central supermassive
black hole is clearly overmassive for a host galaxy of that luminosity, but not
unprecedented, given some recent findings of other ``overmassive'' black holes
in nearby galaxies.
