The Structure of the X-ray and Optical Emitting Regions of the Lensed
  Quasar Q 2237+0305
  We use gravitational microlensing to determine the size of the X-ray and
optical emission regions of the quadruple lens system Q 2237+0305. The optical
half-light radius, log(R_{1/2,V}/cm)=16.41\pm0.18 (at lambda_{rest}=2018 \AA),
is significantly larger than the observed soft,
log(R_{1/2,soft}/cm)=15.76^{+0.41}_{-0.34} (1.1-3.5 keV in the rest frame), and
hard, log(R_{1/2,hard}/cm)=15.46^{+0.34}_{-0.29} (3.5-21.5 keV in the rest
frame), band X-ray emission. There is a weak evidence that the hard component
is more compact than the soft, with log(R_{1/2,soft}/R_{1/2,hard}) \sim
0.30^{+0.53}_{-0.45}. This wavelength-dependent structure agrees with recent
results found in other lens systems using microlensing techniques, and favors
geometries in which the corona is concentrated near the inner edge of the
accretion disk. While the available measurements are limited, the size of the
X-ray emission region appears to be roughly proportional to the mass of the
central black hole.
