The Variable Optical Polarization and FERMI Observations of PMN
  J0948+0022
  We report on observations of the {\gamma}-ray and optical photopolarimetric
behavior of the radio-loud, narrow line type-1 Seyfert galaxy PMN J0948+0022
over a twenty seven month period. As this object has recently been suggested to
represent a prototype of an emerging class of blazar-like objects, the observed
properties are compared to those of blazars. We extract doubling timescales of
roughly 4 hours for the optical and {\gamma}-ray bands. The rapid
microvariability in the optical/NIR, significant and variable optical
polarization, and strong yet rapidly-variable {\gamma}-ray emission we observe
for PMN J0948+0022 are all classical observational characteristics associated
with blazars. However, since these observations do not show a clear correlation
between the {\gamma}-ray and optical behavior, they do not offer conclusive
proof that the emissive behavior of PMN J0948+0022 is due to a relativistic jet
oriented close to our line of sight.
