Discovery of Energy Dependent X-ray Microlensing in Q2237+0305
  We present our long term Chandra X-ray monitoring data for the
gravitationally lensed quasar Q2237+0305 with 20 epochs spanning 10 years. We
easily detect microlensing variability between the images in the full (0.2--8
keV), soft (0.2--2 keV), and hard (2--8 keV) bands at very high confidence. We
also detect, for the first time, chromatic microlensing differences between the
soft and hard X-ray bands. The hard X-ray band is more strongly microlensed
than the soft band, suggesting that the corona above the accretion disk thought
to generate the X-rays has a non-uniform electron distribution, in which the
hotter and more energetic electrons occupy more compact regions surrounding the
black holes. Both the hard and soft X-ray bands are more strongly microlensed
than the optical (restframe UV) emission, indicating that the X-ray emission is
more compact than the optical, confirming the microlensing results from other
lenses.
