Radio to X-ray luminosity ratio vs. the rotation period. TESS and X-ray flares are shown with open filled circles and stars, respectively, while radio bursts with open filled squares. UCDs that are placed on the x-axis are undetected with both X-ray and radio instruments. The solid horizontal line at log(L_R,v/L_x) 15.5 represents the relation of Güdel & Benz (1993) as a function of P_rot, while the vertical line at P_rot = 0.2 day is from Pineda et al. (2017) to separate the radio-loud from the radio-quiet regime.