A quantum mechanical approach to establishing the magnetic field orientation from a maser zeeman profile
Date
2014
Authors
McClure-Griffiths, Naomi
Green, J A
Gray, M.D.
Robishaw, T.
Caswell, Jams
Journal Title
Journal ISSN
Volume Title
Publisher
Blackwell Publishing Ltd
Abstract
Recent comparisons of magnetic field directions derived from maser Zeeman splitting with those derived from continuum source rotation measures have prompted new analysis of the propagation of the Zeeman split components, and the inferred field orientation. In order to do this, we first review differing electric field polarization conventions used in past studies. With these clearly and consistently defined, we then show that for a given Zeeman splitting spectrum, the magnetic field direction is fully determined and predictable on theoretical grounds: when a magnetic field is oriented away from the observer, the left-hand circular polarization is observed at higher frequency and the right-hand polarization at lower frequency. This is consistent with classical Lorentzian derivations. The consequent interpretation of recent measurements then raises the possibility of a reversal between the large-scale field (traced by rotation measures)and the small-scale field (traced by maser Zeeman splitting).
Description
Keywords
Keywords: Magnetic fields; Masers; Polarization; Radiative transfer
Citation
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Source
Monthly Notices of the Royal Astronomical Society
Type
Journal article
Book Title
Entity type
Access Statement
Open Access