GBT22A-155

Magnetic Field Detection in CRRL Emission towards DR 21

Abstract

Full-Stokes GBT observations of carbon radio recombination lines from a photodissociation region in the molecular cloud DR 21 have yielded a tantalizing but marginal detection of the Zeeman effect. These observations were conducted in 2006 with the then newly operational full-polarization mode of the GBT autocorrelation spectrometer (ACS); eight CRRLs were observed over 20.5 hours for an on-source integration time of 13.3 hours. We propose to confirm this detection by configuring VEGAS to observe 16 CRRLs across C-band and observing for sufficiently long (32 hours) to achieve a 5-sigma detection of the line-of-sight magnetic field.

Investigators

Name	Institution
Timothy Robishaw *	Herzberg Astronomy & Astrophysics Research Centre, National Research Council Canada
Trey Wenger	Wisconsin at Madison, University of
Pedro Salas	Green Bank Observatory
Carl Heiles	California at Berkeley, University of

* indicates the PI