[O III] and Hα luminosity [erg s^-1] (left and right panel, respectively) as a function of radio luminosity at 178 MHz [erg s^-1 Hz^-1]. Blue circles are HEG (crossed circles are BLO), red squares are LEG, green pluses are ELEG, the cyan asterisk is the star forming galaxy, while the black triangles are spectroscopically unclassified galaxies. The two solid lines represent the best linear fit obtained for the HEG and LEG sub-populations separately. When possible, we further mark the LEG according to their FR type: crossed squares are FR II/LEG and dotted squares are FR I/LEG. The filled symbols are derived from the new data presented in this paper.