Multi-frequency light curve of Cygnus X-3 from 2007 December 12 to 2009 September 26 (MJD: 54 450−55 100). From top to bottom: radio flux density [RATAN-600 (2.15, 4.8, 11.2 GHz) and AMI-LA (15 GHz)], soft X-ray count rate [RXTE/ASM (3−5 keV)], hard X-ray count rate [Swift/BAT (15−50 keV)], and gamma-ray photon fluxes [AGILE-GRID (above 100 MeV)]. In the bottom panel, gray regions represent the AGILE pointing at the Cygnus region; magenta points are the main events of γ-ray activity with (see Table A.1), black points are the γ-ray detections with , and dark-gray arrows are the 2σ upper limits related to . The dashed lines in the panels of the RXTE/ASM and Swift/BAT count rate represent the transition level of 3 counts s^-1 and 0.02 counts cm^-2 s^-1 respectively (see Sect. 3.1 for details).