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Title: Reverberation mapping of the emission line regions of Seyfert galaxies and quasars

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/159843· OSTI ID:5080299

Variations in the strengths of the central photoionization source in a quasar or Seyfert galaxy will generate variations in the strengths and profiles of the emission lines. These ''reverberations'' in the emission lines will lag behind the continuum variations due to light travel time effects. A procedure is described for analyzing a time series of measurements of both the continuum and the lines. This procedure permits direct verification of the assumed causal connection of the lines to the continuum. We demonstrate that if the emission line region has a high degree of symmetry, then it is possible to invert the time-dependent line profiles and obtain the phase space distribution of the emission-line gas: i.e., its emissivity and the moments of its velocity distributions as functions of position. The cases of spherical and disk symmetry are considered in detail; the case of a straight jet, which may be relevent to correlated optical and radio variations, is discussed briefly. Explicit calculations of expected line variations have been carried out for several simple models. We suggest that with recently developed instrumentation it should now be possible to apply this technique to Seyfert galaxies. Long term, highly accurate observations will be required for the application to quasars.

Research Organization:
Theoretical Astrophysics, California Institute of Technology
OSTI ID:
5080299
Journal Information:
Astrophys. J.; (United States), Vol. 255:2
Country of Publication:
United States
Language:
English