Left panels: radio power against the absolute magnitude for galaxies in three samples. Galaxies with jet-like radio sources are denoted as open symbols, and those with compact sources are denoted as filled symbols. The dotted line represents the cutoff for a complete sample of radio objects. The down-wards arrows are the upper limit of the undetected galaxies in radio. Right panels: the same but for radio-to-luminosity ratio against the absolute magnitude for three samples.