HDO(1₁₀–1₁₁) spectra (in T_B scale) derived from the PdBI image and integrated over the whole emitting region (upper panel), and the area of the two structures called A and B (middle panels). The spectral resolution is 1.4 km s^-1. Bottom panel reports the HDO(1₁₀–1₁₁) low-spectral resolution (5 km s^-1) spectrum as observed with the 30-m IRAM antenna. The ambient LSR velocity (+4.7 km s^-1) is marked by the vertical dashed line.