Comparison of the CS 5−4 spectrum (solid) toward the central position of Cha-MMS1 and CO 6−5 spectra (dotted) taken at the central position and in the north-east direction toward the nearby Class I protostar. The offset position of each spectrum is given in arcseconds relative to the central position. The CO 6−5 spectra are shifted vertically by a step of 1 K for clarity. The solid vertical line roughly corresponds to the velocity of the CO 6−5 red peak, while the dashed line marks the velocity of the peak of the CS 5−4 excess emission.