Burst isotropic luminosity as function of the observational frequency for all the instruments involved in the MWL campaign. The dots are the luminosities of the bursts SRT-P-02 and uGMRT-03. The empty triangle markers represent the non punctual upper limits (ULs), that is coincident with no radio bursts. The filled triangles are punctual ULs, coincident with a radio burst detection (see Sect. 4). All optical ULs are converted in the V band and for a 1 ms burst.