WISE W1 and W2 photometric measurements superimposed with 6.7 GHz CH₃OH maser integrated flux density. Circles indicate the values of the WISE measurements for every epoch; transparent crosses indicate the singular WISE photometric measurements. The error bars correspond to standard deviation. Only measurements with cc_flags of 0 (unaffected by known artifacts) or h (possible contamination by scattered light from a nearby bright source), and qual_frame values no lower than 5 (high image quality) are shown. Two bottom panels show 6.7 GHz integrated flux density vs. WISE singular measurements. Here, a stricter quality criterion was also used: only ph_qual of A (source detected in this band with S/N > 10). Values in the boxes are Pearson correlation coefficients.