Detection of the CN Zeeman effect in molecular clouds

Observations of the Zeeman effect in the 3 mm lines of CN have been carried out with the 30 m IRAM telescope toward seven dense molecular clouds. Detections were achieved toward the Orion Molecular Cloud 1 (OMC1), toward two cores in the DR21OH molecular cloud, and probably toward the M17SW molecular cloud. The line-of-sight magnetic field strengths inferred are B-los(OMC1)= -0.36 +/- 0.08, B-los(DR21OH(1)) = -0.36 +/- 0.10, B-los(DR210H(2)) = -0.71 +/- 0.12, and B-los(M17SW) = -0.33 +/- 0.14 mG. The theoretical implications of these results are discussed.