Gray-scale image of H₂CO (4_1,4−3_1,3) integrated in a velocity range between −4.6 km s⁻¹ and 9.9 km s⁻¹ overlaid with contours of integrated line emission for multiple molecular species, as shown in the upper left corner. Contours are drawn at 3σ, in steps of 2σ between 4σ and 10σ and in steps of 10σ afterwards. Top panels: a) Additional contours are drawn for N₂H⁺ (18σ) and DCO⁺ (15σ). Major differences between displayed species can be seen around the region of the pre stellar core 16293E. b) Additional contours are drawn for CS (9σ), SO (15σ), and C¹⁷O (14σ). Bottom panels: c) Additional contours are drawn for HNC (14σ), HCN (16σ), and CS (9σ). d) Additional contours are drawn for HCO⁺ (25, 55σ) and H¹³CO⁺ (5, 27σ). Notice the differences in peak emission around the E1 region, for which most species peak southern of formaldehyde. White markers show positions discussed in previous sections.