Integrated photon flux above 1 TeV as a function of the time with respect to the periastron passage indicated with the vertical dashed line. The corresponding orbital phases (mean anomaly) are shown on the upper horizontal axis. The data from the 2004 (blue squares) (Aharonian et al. 2005b), 2007 (red triangles) (Aharonian et al. 2009), and 2011 (green circles) observation campaigns are shown. For the 2004 and 2011 data the flux is shown in daily bins while for the 2007 data the flux is shown in monthly bins for clarity.