H₂CO(3_0,3−2_0,2) and D₂CO(4_0,4−3_0,3) map spectra toward the ρ Oph A cloud. The (0″,0″) position is the same as in Fig. 1. The vertical scale in each spectrum represents T_mb scale in K and the horizontal scale is velocity v_LSR with respect to local standard of rest in km   s^-1 as shown in the upper rightmost panel.