BPT plot with [OIII]/Hβ versus [N II]/Hα. Galaxies from the AGN as well as the control sample of star-forming and passive galaxies are shown in blue, deep pink, and red, respectively. The empirical (Kauffmann et al. 2003) and theoretical (Kewley et al. 2001) boundaries between starburst and AGN galaxies are marked with black straight and dashed lines, respectively. The underlying blue cloud of points is from the MPA-JHU emission line analysis of SDSS DR7 galaxies (Brinchmann et al. 2004).