The Use of Faraday Rotation Sign Maps as a Diagnostic for Helical Jet Magnetic Fields
We present maps of the sign of the Faraday Rotation measure [sign(RM)] obtained from multi-frequency radio observations on the Very Long Baseline Array (VLBA). Many of the Active Galactic Nuclei (AGN) considered have B-field structures with a central "spine" of B-field orthogonal to the je...
| Main Authors: | , |
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| Format: | Text |
| Language: | unknown |
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arXiv
2011
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| Online Access: | https://dx.doi.org/10.48550/arxiv.1109.2507 https://arxiv.org/abs/1109.2507 |
| Summary: | We present maps of the sign of the Faraday Rotation measure [sign(RM)] obtained from multi-frequency radio observations on the Very Long Baseline Array (VLBA). Many of the Active Galactic Nuclei (AGN) considered have B-field structures with a central "spine" of B-field orthogonal to the jet and/or a longitudinal B-field near one or both edges of the jet. This structure can plausibly be interpreted as being caused by a helical/toroidal jet magnetic field. Faraday Rotation is a rotation of the plane of polarization that occurs when the polarized radiation passes through a magnetized plasma. The sign of the RM is determined by the direction of the line-of-sight B-Field in the region causing the Faraday Rotation, and an ordered toroidal or helical magnetic field associated with an AGN jet will thus produce a distinctive bilateral distribution of positive and negative RMs across the jet. We present and discuss sign(RM) maps and their possible interpretation regarding the magnetic field geometries for several sources. : From the proceedings of Beamed and Unbeamed Gamma-Rays from Galaxies, April 11-15, 2011, Muonio, Finland. 5 pages, 4 figures |
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