Left: flux vs. time of Sgr A* for the VLA data (top six graphs) and the 100 GHz ALMA data (bottom graph). The fitted FRED function is plotted as a green (gray) curve, the position of the maxima is plotted as a vertical red (dark gray) line with the uncertainty in the fit superimposed as a red-shaded (dark gray) region. Green-shaded (light gray) regions indicate the uncertainty on the fits obtained by randomly dropping half of the data points for 500 iterations – see Sect. 3 for details. Right: flux vs. time for the calibrator sources (J1744-3116 for the VLA data, NRAO530 for the ALMA data).