The Evolution Sequence in Narrow-Line and Broad-Line SEYFERT 1 Galaxies

Collecting a sample of 50 narrow-line Seyfert 1 galaxies (NLS1s) and 44 broad-line Seyfert 1 galaxies (BLS1s), we show that the theoretical maximum starburst line derived by Kewley et al. can separate well BLS1s from NSL1s on the BPT diagrams, and the [N II]λ 6584/Hα ratio increases along the list from NLS1s to BLS1s. We suggest that: (1) they have a sequence from low metallicities to high metallicities between NLS1s and BLS1s; (2) with regard to the ``star-froming sequence'' of Kewley et al. who noted that it forms a tight sequence from low metallicities to high metallicities, the sequence may be connected to the NLS1-BLS1 sequence of ``active galactic nucleus (AGN)'' sequences.