Quasar Accretion Disk Sizes From Continuum Reverberation Mapping From
  the Dark Energy Survey
  We present accretion disk size measurements for 15 luminous quasars at $0.7
\leq z \leq 1.9$ derived from $griz$ light curves from the Dark Energy Survey.
We measure the disk sizes with continuum reverberation mapping using two
methods, both of which are derived from the expectation that accretion disks
have a radial temperature gradient and the continuum emission at a given radius
is well-described by a single blackbody. In the first method we measure the
relative lags between the multiband light curves, which provides the relative
time lag between shorter and longer wavelength variations. From this, we are
only able to constrain upper limits on disk sizes, as many are consistent with
no lag the 2$\sigma$ level. The second method fits the model parameters for the
canonical thin disk directly rather than solving for the individual time lags
between the light curves. Our measurements demonstrate good agreement with the
sizes predicted by this model for accretion rates between 0.3-1 times the
Eddington rate. Given our large uncertainties, our measurements are also
consistent with disk size measurements from gravitational microlensing studies
of strongly lensed quasars, as well as other photometric reverberation mapping
results, that find disk sizes that are a factor of a few ($\sim$3) larger than
predictions.
