Long-term light curves of MAGIC J2001+439 in 2010 and 2011. a) Fermi-LAT light curve above 1 GeV with a monthly binning. b) Fermi-LAT light curve above 1 GeV with a weekly binning. The gray arrows report the flux upper limits at 95% confidence level, which were calculated for the time intervals with TS < 4. c) Optical R-band light curves. d) Radio light curve at 15 GHz. The horizontal dotted lines show the result of a fit with a constant function. See caption of Fig. 3 for further details.