Measuring the Magnetic Field Strength in L1498 with Zeeman‐splitting Observations of CCS

Abstract

We have measured the Zeeman splitting of the CCS JN=32-21 line at 33 GHz toward L1498, a dense preprotostellar core, in an effort to measure the line-of-sight component of its magnetic field. With approximately 35 hr of data on source (70 hr total) in good weather, the data suggest a line-of-sight component of the magnetic field in L1498 of 48+/-31 μG, yielding an upper limit of Blos<100 μG at the 95% confidence level. This upper limit provides some constraints on models. Our results show that the technique we have adopted to measure CCS Zeeman splitting holds great promise for determining magnetic field strengths in cloud cores using lower-frequency transitions, in particular the CCS JN=10-00 line at 11 GHz. At this transition, the frequency splitting per gauss is 3 times that at 33 GHz, the brightness temperature is comparable to the 32-21 line, and receiver systems can be made more sensitive.