An Observational Link between AGN Eddington Ratio and [N ii]λ6583/Hα at 0.6 < z < 1.7

We present an observed relationship between the Eddington ratio (lambda(Edd)) and the optical narrow-emission-line ratio ([N II]lambda 6583/H alpha) of X-ray-selected broad-line active galactic nuclei (AGNs) at 0.6 < z < 1.7. We use 27 near-infrared spectra from the Fiber Multi-Object Spectrograph along with 26 sources from the literature. We show that the lambda(Edd) and [N II]lambda 6583/H alpha ratio at 0.6 < z < 1.7 exhibits a similar anti-correlation distribution of lambda(Edd)-[N II]lambda 6583/H alpha, as has been found for local (< z > = 0.036), ultra-hard, X-ray-selected AGNs. The observed distribution implies that there is a consistent relationship from local to z similar to 1.7, which corresponds from the present time to 4 Gyr old. Further study of high-redshift, low-Eddington-ratio AGNs (log lambda(Edd) < -2) is necessary to determine fully whether the lambda(Edd)-[N II]lambda 6583/H alpha anti-correlation still holds in high-redshift AGNs at low Eddington ratios.