SIMBAD references

CS (2-1) data of the Orion A Cloud obtained with the FCRAO 14 m telescope are shown. The CS (2-1) image shows the clumpy and filamentary structure of the Orion A cloud, as did our previous CS (1-0) image, obtained with the NRO 45 m telescope. The peak intensity T_MB (CS 2-1) decreases more steeply than T_MB (CS 1-0) toward the south along the filament. It is found that the gas density of the CS cores tends to be lower in the south of the cloud, and this explains the above difference in the line-intensity decrease. From CS and C³⁴S data, we estimated the optical depth of CS (2-1) to be moderately high (2-5) and that of CS (1-0) to be typically less than unity.