The Origin of NIII {$\lambda$}990 and CIII {$\lambda$}977 Emission in NGC 1068

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Session 18 -- AGN Spectroscopy
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

[18.12] The Origin of NIII {$\lambda$}990 and CIII {$\lambda$}977 Emission in NGC 1068

Jason W. Ferguson and Gary J. Ferland (University of Kentucky)

We discuss implications of HUT detections of C III {$\lambda$}977 and N III {$\lambda$}990 emission from the Narrow Lined Region (NLR) of the Seyfert 2 galaxy NGC 1068. In their discovery paper Kriss et al. (1992, ApJ, 394, L37) showed that unexpectedly great strength of these lines implies that the emitting gas must be shock heated if the lines are collisionally excited. Here we investigate other processes which excite these lines in photoionization equilibrium. Recombination, mainly dielectronic, and continuum fluorescence, are strong contributors to the line. The resulting intensities are sensitive to the velocity field of the emitting gas, and require that the turbulence be the same order of magnitude as the observed line width. We propose optical observations that will decide whether the gas is collisionally or radiatively heated.

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