Bottom panel: overlay of the ALMA 1.4 mm continuum emission (white contours) on the integrated intensity (moment 0) map (colors) of CHCN K = 3 at an angular resolution of ~0.′′1. The contours are the same as in Fig. 1 (right panel). The synthesized beam isshown in the lower left corner. The white crosses indicate the positions of the NE core and the four sources embedded in the Main core. Top panel: spectra of the CHCN K = 3 and CH₃CNK = 6 transitions toward the 1.4 mm continuum emission peak of sources A (black) and B (red). The red-shifted absorption is clearly detected in both transitions. The vertical blue dashed line indicates the systemic LSR velocity of 96.5 km s.