Reverberation
Mapping (RM)
lBroad lines are photoionized
by the central continuum, which
varies. The line flux follows the
continuum with a time lag t which
is set by the size of the broad-line emitting region and the speed of light.
Recombination timescales are very short, BLR stable, and continuum source small and
central.
Kaspi et al. (2000) studied bright
PG quasars, particularly Hβ, finding that
R=32.9(λLλ5100/1044 erg s-1)0.7 lt-days
For the Hβ
emitting gas.