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M. C. Bottorff, G. J. Ferland (University of Kentucky)
Broad emission lines of Active Galactic Nuclei (AGN) are too bright to be powered by the continuum and too smooth to be produced by thermal clouds. One explanation is large-scale microturbulence. Turbulence has a significant effect on the shape and smoothness of AGN line profiles. If turbulence is in energy equipartition with gravity the line width of a cloud is much wider than the thermal width. The aggregate total line profile is therefore both broad and smooth. Turbulent motions also affect line transfer. The spectrum grows stronger as turbulence increases. Lines more easily escape due to diminished optical depth. Continuum pumping selectively strengthens permitted lines. If turbulence is dissipative low ionization lines are especially enhanced because most of the heat is deposited in the extended H0 neutral zone. With dissipation the "standard" broad line region (BLR) spectrum is obtained with a column density of only ~1022cm-2. A possible consequence of turbulence is a fractal structure. A fractal applied to an AGN is able to account for many emission and absorption features seen in quasars and Seyfert galaxies.
We thank the NSF for its support through grant AST-0071180 and NASA through its LTSA program (NAG5-8212).
Key Words: active nuclei, emission lines, turbulence
The author(s) of this abstract have provided an email address for comments about the abstract: bottorff@pa.uky.edu