Dependence of NLRs sizes on [OIII] luminosity in low redshift AGN with double-peaked broad Balmer emission lines

TL;DR

This study investigates how the sizes of narrow-line regions (NLRs) in low-redshift AGN with double-peaked broad emission lines depend on [OIII] luminosity, confirming consistency with the unified AGN model.

Contribution

It provides the first estimation of NLRs sizes in a small sample of double-peaked broad-line AGN and compares their empirical dependence on [OIII] luminosity with type-2 AGN.

Findings

NLRs sizes are within expected ranges from empirical relations.

No evidence contradicts the unified AGN model based on NLR properties.

Strong correlation between [OIII] luminosity and continuum luminosity.

Abstract

In the manuscript, the simple but interesting results are reported on the upper limits of NLRs sizes of a small sample of 38 low redshift ($z<0.1$) AGN with double-peaked broad emission lines (double-peaked BLAGN), in order to check whether the NLRs sizes in type-1 AGN and type-2 AGN obey the similar empirical dependence on \o3~ luminosity. In order to correct the inclination effects on projected NLRs sizes of type-1 AGN, the accretion disk origin is commonly applied to describe the double-peaked broad H$\alpha$ leading to the determined inclination angles of central disk-like BLRs of the 38 double-peaked BLAGN. Then, considering the fixed SDSS fiber radius, the upper limits of NLRs sizes of the 38 double-peaked BLAGN can be estimated. Meanwhile, the strong linear correlation between continuum luminosity and \o3~ luminosity is applied to confirm that the \o3~ emissions of the 38 double-peaked BLAGN are totally covered in the SDSS fibers. Considering the reddening corrected measured \o3~ luminosity, the upper limits of NLRs sizes of the 38 double-peaked BLAGN are within the 99.9999\% confidence interval of the expected results from the empirical relation between NLRs sizes and \o3~ luminosity in the type-2 AGN. In the current stage, there are no clues to challenge the Unified model of AGN, through the space properties of NLRs.