Planck field toward the M 81 galaxy in the 143 GHz band. The pixel color gives the temperature excess in μK with respect to the mean CMB temperature. The optical extension of the M 81 galaxy is indicated by the inner ellipse with apparent dimensions of 26.9′ and 14.1′, respectively. The four quadrants A1, A2, A3, and A4 are used in the analysis. The thin dashed black line marks the Galactic latitude b = 40° north. We note that the M 82 galaxy is clearly visible as the red spot in the A1 region at about 38′ from the center of M 81.