Integrated intensity maps of the SO 2₂ → 1₁, C³⁴S 3→2, HCS⁺ 2→1, HC¹⁸O⁺ 1→0, HOCO⁺ 4₀₄ → 3₀₃, DCO⁺2 → 1, D¹³CO⁺2 → 1, p-H₂CO 2₀₂ → 2₀₁, and p-HCO 2₀₂ → 2₀₁ lines. The HPBW of the 30-m telescope at each line frequency is drawn in the bottom-left corner of the panel. The stars indicate the positions of B1b-N, B1b-S and B1b-W. The black square shows the position targeted in the unbiased spectral survey.