PACS spectral maps of Serpens SMM1 in the o-H₂O 3₀₃–2₁₂ (174.626 μm); [C ii]157.741 μm; CO J = 17−16 (153.267 μm); both p-H₂O 3₂₂–2₁₁ (89.988 μm) and CO J = 29−28 (90.163 μm); [O i]63.183 μm and OH  J = 9/2⁺–7/2⁻ (65.279 μm) lines (from top to bottom). The center of each spaxel corresponds to its offset position with respect to the protostar at α₂₀₀₀: 18^h29^m49.8^s, δ₂₀₀₀: 1°15′20.5′′. The Y-axis for each transition represents the normalized line flux (in the −0.2 to 1.2 range) with respect to the brightest line in the array. The X-axis represents the −550 to 550 km s^-1 velocity scale except for the OH 65.279 μm line (− 350 to 350 km s^-1) and the p-H₂O 89.988 μm and CO 90.163 μm lines (− 1000 to 1000 km s^-1). The vertical dashed lines show the position of the rest wavelengths. Blue and red arrows show the approximated outflow direction. The green box represents the central spaxel centered at the protostar position whereas the red and blue boxes represent postions in the red and blue outflow lobes respectively. Note that the PSF is relatively constant for λ  ≲  100 μm (FWHM  ≃  spaxel size  ≃9.4′′) but increases at longer wavelengths.