Identification Of Outflows And Candidate Dual Active Galactic Nuclei In SDSS Quasars At Z=0.8-1.6 [article]

Joel C. Berrier
We present a sample of 131 quasars from the Sloan Digital Sky Survey at redshifts 0.8 < z < 1.6 with double peaks in either of the high-ionization narrow emission lines [Ne v] λ3426 or [Ne iii] λ3869. These sources were selected with the intention of identifying high-redshift analogs of the z < 0.8 active galactic nuclei (AGNs) with double-peaked [O iii] λ5007 lines, which might represent AGN outflows or dual AGNs. Lines of high ionization potential are believed to originate in the inner,
more » ... photoionized portion of the narrow line region, and we exploit this assumption to investigate the possible kinematic origins of the double-peaked lines. For comparison, we measure the [Ne v] λ3426 and [Ne iii] λ3869 double peaks in low-redshift (z < 0.8) [O iii]-selected sources. We find that [Ne v] λ3426 and [Ne iii] λ3869 show a correlation between line splitting and line width similar to that of [O iii] λ5007 in other studies, and the velocity splittings are correlated with the quasar Eddington ratio. These results suggest an outflow origin for at least a subset of the double peaks, allowing us to study the high-ionization gas kinematics around quasars. However, we find that a non-negligible fraction of our sample show no evidence for an ionization stratification. For these sources, the outflow scenario is less compelling, leaving the dual AGN scenario as a viable possibility. Finally, we find that our sample shows an anti-correlation between the velocity-offset ratio and luminosity ratio of the components, which is a potential dynamical argument for the presence of dual AGNs. Therefore, this study serves as a first attempt at extending the selection of candidate dual AGNs to higher redshifts.
doi:10.15781/t2j23v fatcat:ksyleb473fezvcpn3y66k6mcra