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Polarization,
Faraday Rotation
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Synchrotron
radiation is highly polarized
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perpendicular
to the direction of B. Why?
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Linear
polarized wave is rotated as it moves
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through
ionized gas:
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– |
Δθ = 4.64x106 nt Bp Lλ2
where n is the cgs
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density
of thermal electrons, B is the parallel
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magnetic
field in Gauss, L is the length in kpc,
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and
the wavelength is in cm. Measure at
two
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wavelengths
to correct for and measure the
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Faraday
rotation. Can be helpful when
looking
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at
two radio lobes (e.g., which is foreground).
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