EPoS Contribution
EPoS Contribution
Magnetic Field Observations at High Angular Resolution in Star Forming Regions

Anuj Sarma
DePaul University, Chicago, USA
Magnetic fields are known to play an important role in star formation, yet the number and extent of magnetic field observations is still quite small. The Zeeman effect in radio frequency spectral lines allows for the most direct measurement of magnetic fields in star forming regions. I will present some recent results, including detection of the Zeeman effect in 1665 and 1667 MHz OH absorption lines toward the star forming regions S88B and NGC 6334, detection in the 22 GHz water maser line toward OH43.8-0.1, and an upper limit in the 22 GHz water maser line toward the pre-UC HII region 22506+5944. Zeeman observations in OH absorption lines toward regions backed by bright continuum sources, such as in S88B and NGC 6334, allow us to map the magnetic field at high angular resolution in star forming regions, and we will report on the detection of fields of the order of several hundred microgauss. Zeeman observations in the water maser line allow for the measurement of magnetic fields in the highest density regime in star forming regions at some of the earliest stages of the formation of a star, including mapping the field along shock interfaces. We will report on the detection of fields of the order of tens of milligauss via the Zeeman effect in the 22 GHz water maser line in OH43.8-0.1. As higher resolution becomes available for many other species in future, these data allow for comparisons and contrasts in the observational arena; moreover, they provide observational constraints on theoretical and numerical models.