Emission Lines Indicating a Universal L/M Ratio for the Central Engine in AGN ?
Assuming the velocity dispersion of the emission-line clouds is induced by gravity, we calculate the dynamic mass (M ∼ v 2 r/G) of the central object in a sample of ∼ 50 Seyfert 1 nuclei and ∼ 40 nearby quasars. Typical values are 108M⊙ for Seyferts and 109M⊙ for quasars. The dynamic mass is found to be proportional to the continuum luminosity (at the ∼ 20σ confidence level), which suggests a universal value of L/L Edd . For the optical band we find log <L c /L Edd >=-2.0±0.3. Applying the same technique to the OIII line, one can estimate the dynamic mass within the radius of the narrow-line region (∼ 100 pc). For some 50 objects of the sample above, this mass is found to be well correlated with the continuum luminosity and with the dynamic mass estimated from the Hβ line.
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