Left to right: [CII] channel maps centered on −500 km s^-1, systemic velocity, + 100 km s^-1, and + 350 km s^-1, respectively, all relative to z = 3.427 and with a channel width of 87 km s^-1. Contours show the continuum in the line-free spectral windows and are given for 3, 5, 10, 15, and 20σ. Negative contours are −3σ. The inset shows the SMA 850 μm image with all counter images; the gray circle is the primary beam of ALMA. The other panels show image A. The ALMA beam size in the lower left corner of each map corresponds to 150 pc at z = 3.4 (for μ = 20).