  High cadence, high quality observations of active galactic nuclei (AGN)
clearly show continuum variations with lags, relative to the shortest observed
variable UV continuum, that increase with wavelength ("lag spectra"). These
have been attributed to the irradiation and heating of the central accretion
disk by the central X-ray emitting corona. An alternative explanation,
connecting the observed lag-spectra to line and continuum emission from gas in
the broad line region (BLR), has also been proposed. In this paper I show the
clear spectral signature of the time-dependent diffuse gas emission in the
lag-spectrum of 6 AGN. I also show a new lag-luminosity relationship for 9
objects which is a scaled down version of the well known lag(H-beta)-L(5100A)
relationship in AGN. The shape of the lag-spectrum, and its normalization, are
entirely consisted with diffuse emission from radiation pressure supported
clouds in a BLR with a covering factor of about 0.2. While some contributions
to the continuum lag from the irradiated disk cannot be excluded, there is no
need for this explanation.
