BPT-diagram (Baldwin et al. 1981) of the sources in our Hα λ6563-subsample for which we measure [N II] λ6584. All galaxies fall in the star-forming region of the diagram. The filled and open circles have S/N([N II] λ6584) > 3 and < 3, respectively, and the 5 sources encircled in red are detected in X-rays (Luo et al. 2016). The solid and dashed curve show the AGN boundary and maximum starburst line from Kauffmann et al. (2003) and Kewley et al. (2001), respectively.