We present the results of single-dish observations of CS J = 2-1 and J = 3-2 and interferometric observations of CO J = 1-0 toward the center of the quadrupolar molecular outflow in L723. We have detected a compact CS condensation having a size of 0.04 pc and a mass of 0.55 M☉ toward the northeastern radio continuum source VLA 2 (AER91 2). The CO outflow also shows the distribution centered at VLA 2. These results suggest that the source VLA 2 is the young stellar object that is powering the conspicuous molecular outflow system. On the other hand, there is no enhancement in the CS intensity or the CO outflow distribution toward the southwestern radio continuum source VLA 1 (AER91 1), indicating that the source VLA 1 does not contribute to the morphology of the quadrupolar outflow in L723. The CO distribution observed with the interferometer delineates the western edge of the blue lobe and the northeastern edge of the red lobe revealed in the single-dish map, suggesting that the outflow in L723 is a single bipolar outflow with a wide opening angle of 120°-170° rather than two independent outflows. We found signs of interaction between the blueshifted outflow and the dense ambient gas: (1) there is a compact CS clump blueshifted by ~1 km s-1, the distribution of which shows anticorrelation with the blueshifted CO outflow; (2) both CS and NH3 spectra show the line broadening toward the blueshifted clump; and (3) there is a temperature enhancement at the boundary of the blueshifted clump of CS emission. It is likely that such interaction with the dense ambient gas has the increased opening angle of the outflow, which accounts for the quadrupolar morphology.
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