Mapping the AGN Broad Line Region by Reverberation
Subject Category: BH AND NS BINARIES
Proposal Number:15700897
Title: Mapping the AGN Broad Line Region by Reverberation
PI Name: Peterson
We propose to make the first reverberation map of the detailed
response of the broad UV emission lines, crucial
to studies of the evolution of black hole masses across cosmic time,
to the variable continuum using the Seyfert
1 galaxy NGC 5548. Reverberation mapping is the only direct method for
measuring black hole masses beyond
the local universe, using time resolution as a substitute for spatial
resolution. This program will provide the first
determination of the structure of a high-ionization broad-line
region. NGC 5548 is known to vary on short time
scales and has a short time lag between continuum and emission-line
flux variations, assuring that physically
meaningful, empirical, model-independent velocity-delay maps for the
strong UV lines (C IV and Lyman alpha)
can be recovered reliably given our experimental design. Realistic
numerical simulations based on the known
statistical properties of this source demonstrate that velocity-delay
maps can be well-determined with 180
consecutive daily visits, even allowing for safing events or other
occasional interruptions. Obtaining unique
velocity-delay maps for strong emission lines will be a
ground-breaking accomplishment for HST; these maps
will clarify the nature of the broad-line region, its role in the
apparently complicated accretion/outflow process,
and determine definitively the veracity and accuracy of the AGN
reverberation-based black hole masses that are
now a key component of any study of black hole growth, evolution, and
the role of feedback in the evolution of
galaxies. We leverage this program with a well-designed public-domain
extragalactic deep-field parallel
program
