Maps of the integrated intensity distributions (left) and the velocity fields (right) of the 183 and 325 GHz water lines. Integrated intensity maps: phase center is located at Arp 220 West (α = 15:34:57.220, δ = +23:30:11.60). The contours start at 5σ and are spaced in steps of 10σ (1σ(183 GHz) = 3.9 mJy km s^-1, 1σ(325 GHz) = 5.4 mJy km s^-1). Velocity fields: color scale is identical for both lines (5200 km s^-1–5600 km s^-1) and the velocity contours start at 5280 km s^-1 and are spaced in steps of 30 km s^-1. North is up, east to the left. The beam (0.79′′ × 0.71′′) is indicated in the bottom right corner of each image. The bar in the lower left corner represents a spatial scale of 200 pc.