Emission of the main species (H₂S and both OCS lines) in the inner core of protostars BlbS, HH211MMS, IRAS2A, and IRAS4B. The color map represents the > 3σ emission integrated images in a 4″×4″ square region. The color scale, shown at the right of each map, is the brightness temperature in Kelvin. The white contours represent 10%, 30%, 50%, 70%, and 90% of the peak temperature. The pink star shows the position of the protostar, determined by the position of the maximum emission in the continuum (Tobin et al. 2016b). The green cross marks the point with maximum emission of the line.