NIKA M 87 Stokes I, Q, and U maps at 260 GHz (top) and 150 GHz (bottom). For display purposes, at 260 GHz, the Q and U maps are smoothed with a Gaussian filter of 6 arcsec and the I map of 4 arcsec. At 150 GHz the Q and U maps are also smoothed to 4 arcsec, while the I map is not smoothed. The contours in Q and U represent the intensity map for each frequency, starting from 0.2 Jy/beam with steps of 0.2 Jy/beam. Polarization vectors are plotted in red in the intensity image when I > 0 and P > 2σ_P.