Structure of the Accretion Disk in the Lensed Quasar Q2237+0305 from
  Multi-Epoch and Multi-Wavelength Narrow Band Photometry
  We present estimates for the size and the logarithmic slope of the disk
temperature profile of the lensed quasar Q2237+0305, independent of the
component velocities. These estimates are based on six epochs of
multi-wavelength narrowband images from the Nordic Optical Telescope. For each
pair of lensed images and each photometric band, we determine the microlensing
amplitude and chromaticity using pre-existing mid-IR photometry to define the
baseline for no microlensing magnification. A statistical comparison of the
combined microlensing data (6 epochs $\times$ 5 narrow bands $\times$ 6 image
pairs) with simulations based on microlensing magnification maps gives Bayesian
estimates for the half-light radius of $R_{1/2}=8.5^{+7.5}_{-4.0}\sqrt{ \langle
M \rangle/0.3\, M_\odot}$ light-days, and $p=0.95\pm0.33$ for the exponent of
the logarithmic temperature profile $T\propto R^{ -1/p}$. This size estimate is
in good agreement with most recent studies. Other works based on the study of
single microlensing events predict smaller sizes, but could be statistically
biased by focusing on high-magnification events.
