The Diagnostics and Possible Evolution in Active Galactic Nuclei Associated With Starburst Galaxies

We present a large sample which contains 45 Seyfert 1 galaxies (Sy1s), 46 hidden broad-line region (HBLR) Seyfert 2 galaxies (Sy2s), 57 non-HBLR Sy2s, and 22 starburst galaxies to distinguish their properties and to seek the possible evolution of active galactic nuclei (AGNs) and starburst galaxies. We show that (1) using a plot of [O III] ł5007/H/alpha versus [N II] ł6584/H/alpha of standard optical spectral diagnostic diagrams, we find that a equation can separate well non-HBLR Sy2s and HBLR Sy2s; (2) the emission-line ratios and both the combination of the ratios and polycyclic aromatic hydrocarbon (PAH) strength are utilized effectively to separate starburst galaxies and Seyfert galaxies; (3) we compare a number of quantities from the data and confirm well the separations with statistics; (4) on the basis of statistics, we suggest that HBLR Sy2s may be the counterparts of Sy1s at edge-on orientation. In addition, we discuss the possibility of starburst galaxies evolving to non-HBLR Sy2s and HBLR Sy2s and then evolving to Sy1s based on the statistical analysis.

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