First detection of circular polarization in 4.7 GHz excited OH masers

TL;DR

This paper reports the first detection of circular polarization in 4.7 GHz excited OH masers, enabling magnetic field measurements in star-forming regions through Zeeman splitting analysis.

Contribution

It presents the first measurement of circular polarization in 4.7 GHz OH masers and discusses implications for magnetic field estimation in star-forming regions.

Findings

Detected circular polarization in 4.7 GHz OH masers.

Estimated magnetic fields of approximately 100 mG.

Analyzed methods for velocity shift determination.

Abstract

We report the first detection of circular polarization in 4.7 GHz excited OH masers in star-forming regions made using full Stokes measurements with the Green Bank 100m telescope. The Zeeman shift between the two circular components provides a measure of the magnetic field pervading these maser spots. Three different methods are used to determine the shift in velocity between the Right Circular Polarization and Left Circular Polarization components. We find fields with $B \sim 100$ mG using archival molecular parameters that have limited precision and uncertain values. Reservations of using 1.7 and 6.0 GHz OH masers to estimate magnetic fields in star-forming regions are discussed.