Fractional variability F_var as a function of the frequency for the light curves shown in Fig. 1. Open markers show the results using the whole campaign for each light curve. Full markers only include quasi-simultaneous data to the VHE data (quasi-simultaneity is defined as temporal agreement with VHE data within 6 h for X-ray and UV data, within 1 day for optical data, and within 3 days for radio and Fermi-LAT data).