PdBI maps per velocity channel of ¹²CO J = 2−1 emission from AC Her. The LSR velocity is indicated in the upper left corners. The first contour and step are 16 mJy, negative contours are indicated by dashed lines. The dark ellipse in the last panel shows the half-power extent of the synthetic beam. The conversion factor from Jy to K is 110 K per Jy/beam, the rms noise measured in the maps is about 4 mJy/beam.