  We use multi-wavelength microlensing measurements of a sample of 10 image
pairs from 8 lensed quasars to study the structure of their accretion disks. By
using spectroscopy or narrow band photometry we have been able to remove
contamination from the weakly microlensed broad emission lines, extinction and
any uncertainties in the large-scale macro magnification of the lens model. We
determine a maximum likelihood estimate for the exponent of the size versus
wavelength scaling ($r_s\propto \lambda^p$ corresponding to a disk temperature
profile of $T\propto r^{-1/p}$) of $p=0.75^{+0.2}_{-0.2}$, and a Bayesian
estimate of $p=0.8\pm0.2$, which are significantly smaller than the prediction
of thin disk theory ($p=4/3$). We have also obtained a maximum likelihood
estimate for the average quasar accretion disk size of $r_s=4.5^{+1.5}_{-1.2} $
lt-day at a rest frame wavelength of $\lambda = 1026~{\mathrm \AA}$ for
microlenses with a mean mass of $M=1 M_\sun$, in agreement with previous
results, and larger than expected from thin disk theory.
