VHE flux versus X-ray flux during the simultaneous MAGIC/NuSTAR/Swift observations. Flux points are computed over time bins of 30 min. From left to right: the X-ray energy bands in the panels are 0.3–3 keV, 3–7 keV and 7–30 keV. In the upper panels, the MAGIC fluxes are in the > 1 TeV band, while in the lower panels they are in the 0.2–1 TeV band. Data points from Swift-XRT are shown with black-filled markers. Fluxes corresponding to each day are plotted in a different colour. The results of the Pearson coefficients (and its significance in σ), DCF and the slope of the linear fits in the log-log plane (with the χ²/d.o.f. values) are indicated in each of the corresponding subplots.