ENLR sizes as a function of total [O iii] luminosity (left panels) and the QSO continuum luminosity at 5100 Å (right panels). The used size definitions are isophotal radius r_iso (upper panels), effective radius r_e (middle panels), and the radius containing 95% of the ENLR flux r₉₅ (lower panels). The solid, dashed and dotted lines in the lower left panel correspond to the ENLR size-luminosity relations of Bennert et al. (2002), Schmitt et al. (2003b), and Greene et al. (2011), respectively. The black filled symbols represent RQQs whereas the red filled symbols highlight the few RLQs in our sample. The green opened circles are measurement for luminous type 2 QSOs as reported by Greene et al. (2011) and the blue triangles are measurements for double-peaked AGN (open symbols denote type 2 and filled type 1 AGN) provided by Fu et al. (2012).