To test dual supermassive black hole model for broad line active galactic nucleus with double-peaked narrow [O iii] lines

Abstract

In this paper, we proposed an interesting method to test the dual supermassive black hole model for active galactic nucleus (AGN) with double-peaked narrow [O iii] lines (double-peaked narrow emitters) through their broad optical Balmer line properties. Under the dual supermassive black hole model for double-peaked narrow emitters, we could expect statistically smaller virial black hole masses estimated by observed broad Balmer line properties than true black hole masses (total masses of central two black holes). Then, we compare the virial black hole masses between a sample of 37 double-peaked narrow emitters with broad Balmer lines and samples of Sloan Digital Sky Survey selected normal broad line AGN with single-peaked [O iii] lines. However, we can find clearly statistically larger calculated virial black hole masses for the 37 broad line AGN with double-peaked [O iii] lines than for samples of normal broad line AGN. Therefore, we give our conclusion that the dual supermassive black hole model is probably not statistically preferred to the double-peaked narrow emitters, and more efforts should be necessary to carefully find candidates for dual supermassive black holes by observed double-peaked narrow emission lines.