Moment 0 maps (contours) overlaid on moment 1 maps (color; in units of km s^-1 in the LSR frame) of the ¹³CO (2–1; left) and C¹⁸O (2–1; right) emission in HL Tau obtained with our ALMA observations. Crosses denote the position of HL Tau. Blue and red arrows show the directions of the blue- and redshifted outflows. Blue filled ellipses present the sizes of the synthesized beams. In the ¹³CO map, contour levels are 5%, 10%, 15%, 30%, 50%, and 80% of the peak intensity, where the 5% level corresponds to 4.5σ (1σ = 13.7 mJy Beam^-1 km s^-1). The contour levels in the C¹⁸O map are 5%, 15%, 30%, 60%, and 90% of the peak intensity, where the 5% level corresponds to 2σ (1σ = 11.6 mJy Beam^-1 km s^-1).