Magnetic Fields in Interstellar Masers

Abstract

Zeeman splitting in the spectra of molecular masers that arise in the envelopes of newly formed stars (called interstellar masers) offers a method of estimating the magnetic field in these dense regions (106–1011 cm−3). The magnetic field strengths in regions of OH and H2O masers scale as the square root of the density when compared to the density and field of the ambient interstellar medium. The direction of the field in OH masers may help trace the large scale structure of the magnetic field in the Galactic spiral arms.