(Proposal ID) S11B-029 (PI) Matsuoka, Kenta (Proposal Title) The AGN-Starburst Connection traced by Nitrogen-Loud Quasars (Abstract) The connection between the active galactic nucleus (AGN) and star formation activity is one of the most important issues in understanding the co-evolution of supermassive black holes (SMBHs) and galaxies. In our recent study (Matsuoka et al. 2011, A&A, 527, A100), by using SDSS quasar spectra we found that the emission-line flux ratios involving nitrogen line correlate with the Eddington ratio. This correlation suggests that the mass accretion in quasars is associated with a post-starburst phase, when AGB stars enrich the interstellar medium with nitrogen. It is extremely important to pursue whether this argument is correct, in order to investigate the relation between the star formation and ignition timing of AGNs, and also to assess which stellar population regulates the growth of SMBH. In this proposal, we examine the connection between the AGN and post-starburst described above by focusing on the nitrogen-loud quasars that show incredibly strong emission lines of nitrogen, and high accretion rate; we investigate their gas metallicity of narrow-line region and Eddington ratio by using [Oiii] lambda 5007 and H beta lines, respectively.