Measurement of Magnetic-Field Strengths in Molecular Clouds: Detection of OH Line Zeeman Splitting

1987 ◽  
pp. 55-57
Author(s):  
I. Kazès ◽  
R. M. Crutcher ◽  
T. H. Troland
Keyword(s):  
Magnetic Field ◽  
Molecular Clouds ◽  
Zeeman Splitting ◽  
Field Strengths

scholarly journals Measurement of Magnetic-Field Strengths in Molecular Clouds: Detection of OH Line Zeeman Splitting

1987 ◽  
Vol 115 ◽  
pp. 55-57
Author(s):  
I. Kazès ◽  
R. M. Crutcher ◽  
T. H. Troland
Keyword(s):  
Magnetic Field ◽  
Radio Telescope ◽  
Molecular Clouds ◽  
Stokes Parameter ◽  
Zeeman Splitting ◽  
Spectral Lines ◽  
First Results ◽  
Extended Program ◽  
Interstellar Molecular Clouds ◽  
Field Strengths

We report here the first results of an extended program to measure magnetic-field strengths in interstellar molecular clouds. The very large radio telescope located near Nancay, France, has been used to measure the Stokes-parameter I and V spectra of the 1665 and 1667 MHz lines of OH in emission and in absorption from extended (non-masing) molecular clouds. Signals in the V spectra are produced by Zeeman splitting of the spectral lines; we derive magnetic-field strengths or limits from these data.

scholarly journals New OH Zeeman Measurements of Magnetic Field Strengths in Molecular Clouds

2001 ◽  
Vol 554 (2) ◽  
pp. 916-932 ◽  
Author(s):  
Tyler L. Bourke ◽  
Philip C. Myers ◽  
Garry Robinson ◽  
A. R. Hyland
Keyword(s):  
Magnetic Field ◽  
Molecular Clouds ◽  
Field Strengths

scholarly journals A MERLIN study of 6 GHz excited OH & 6.7 GHz methanol masers in ON1

2007 ◽  
Vol 3 (S242) ◽  
pp. 188-189
Author(s):  
James A. Green ◽  
A. M. S. Richards ◽  
H. Flood ◽  
W. H. T. Vlemmings ◽  
R. J. Cohen
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Cross Correlation ◽  
Massive Star ◽  
Zeeman Splitting ◽  
Massive Star Formation ◽  
Star Formation Region ◽  
Formation Region ◽  
Methanol Masers ◽  
Field Strengths

AbstractMERLIN observations of 6.668-GHz Methanol and 6.035-GHz OH emission from the known massive star-formation region ON1 are presented. Maser components are found to lie at the southern edge of the UCHII with consistent polarization angles across the strongest features. Zeeman splitting of OH shows magnetic field strengths between +0.4 to −5.3 mG and from cross-correlation a tentative methanol magnetic field of −18mG is detected.

scholarly journals Observational Aspects of Magnetic Fields in Molecular Clouds

1990 ◽  
Vol 140 ◽  
pp. 293-300
Author(s):  
T. H. Troland
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Molecular Clouds ◽  
Zeeman Effect ◽  
Growing Body ◽  
Field Strengths

A small but growing body of observational information now exists regarding magnetic field strengths in molecular regions. Most of these data come from study of the Zeeman effect in 18 cm OH lines. The field is strong enough in many such regions to be dynamically important.

scholarly journals Extended OH(1720 MHz) maser emission from supernova remnants

2007 ◽  
Vol 3 (S242) ◽  
pp. 307-311 ◽  
Author(s):  
J. W. Hewitt ◽  
F. Yusef-Zadeh ◽  
M. Wardle ◽  
D. A. Roberts
Keyword(s):  
Magnetic Field ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Zeeman Splitting ◽  
Maser Emission ◽  
Physical Conditions ◽  
Post Shock ◽  
Maser Sources

AbstractCompact OH(1720 MHz) masers have proven to be excellent signposts for the interaction of supernova remnants with adjacent molecular clouds. Less appreciated has been the weak, extended OH(1720 MHz) emission which accompanies strong compact maser sources. Recent single-dish and interferometric observations reveal the majority of maser-emitting supernova remnants(SNRs) have accompanying regions of extended maser emission. Enhanced OH abundance created by the passing shock is observed both as maser emission and absorption against the strong background of the remnant. Modeling the observed OH profiles gives an estimate of the physical conditions in which weak, extended maser emission arises. I will discuss how we can realize the utility of this extended maser emission, particularly the potential to measure the strength of the post-shock magnetic field via Zeeman splitting over these large-scales.

scholarly journals The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

2018 ◽  
Vol 609 ◽  
pp. L3 ◽  
Author(s):  
J. D. Soler ◽  
A. Bracco ◽  
A. Pon
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Zeeman Splitting ◽  
Outer Wall ◽  
High Polarization ◽  
Large Scale Magnetic Field ◽  
Polarization Fraction ◽  
Low Dispersion ◽  
The Magnetic Field ◽  
Field Strengths

Using the 353-GHz polarization observations by the Planck satellite we characterize the magnetic field in the Orion-Eridanus superbubble, a nearby expanding structure that spans more than 1600 square degrees in the sky. We identify a region of both low dispersion of polarization orientations and high polarization fraction associated with the outer wall of the superbubble identified in the most recent models of the large-scale shape of the region. We use the Davis-Chandrasekhar-Fermi method to derive plane-of-the-sky magnetic field strengths of tens of μG toward the southern edge of the bubble. The comparison of these values with existing Zeeman splitting observations of HI in emission suggests that the large-scale magnetic field in the region was primarily shaped by the expanding superbubble.

Magnetic-field strengths from optical polarization data

1967 ◽  
Vol 31 ◽  
pp. 381-383
Author(s):  
J. M. Greenberg
Keyword(s):  
Magnetic Field ◽  
Optical Polarization ◽  
Polarization Data ◽  
Term Model ◽  
Source Of Information ◽  
Field Strengths

Van de Hulst (Paper 64, Table 1) has marked optical polarization as a questionable or marginal source of information concerning magnetic field strengths. Rather than arguing about this–I should rate this method asq+-, or quarrelling about the term ‘model-sensitive results’, I wish to stress the historical point that as recently as two years ago there were still some who questioned that optical polarization was definitely due to magnetically-oriented interstellar particles.

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