Quasar Cartography: from Black Hole to Broad Line Region Scales
  A generalized approach to reverberation mapping (RM) is presented, which is
applicable to broad- and narrow-band photometric data, as well as to
spectroscopic observations. It is based on multivariate correlation analysis
techniques and, in its present implementation, is able to identify
reverberating signals across the accretion disk and the broad line region (BLR)
of active galactic nuclei (AGN). Statistical tests are defined to assess the
significance of time-delay measurements using this approach, and the
limitations of the adopted formalism are discussed. It is shown how additional
constraints on some of the parameters of the problem may be incorporated into
the analysis thereby leading to improved results. When applied to a sample of
14 Seyfert 1 galaxies having good-quality high-cadence photometric data,
accretion disk scales and BLR sizes are simultaneously determined, on a
case-by-case basis, in most objects. The BLR scales deduced here are in good
agreement with the findings of independent spectroscopic RM campaigns.
Implications for the photometric RM of AGN interiors in the era of large
surveys are discussed.
