Faraday Rotation Measure Gradients in 3C273

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Faraday Rotation Measure Gradients in 3C273

• John Wardle, Tingdong Chen,
• Joanne Attridge, Dan Homan,
• Dave Roberts

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Asada et al 2002 RM gradient 70
rad/m2/mas
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RM gradient 70 rad/m2/mas
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RM gradients 25 - 200 rad/m2/mas
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Zavala Taylor 2005

• RM gradient 70 rad/m2/mas

RM gradient 500 rad/m2/mas
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RM gradient 600 rad/m2/mas
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Attridge, Wardle Homan 2005
43 and 86 GHz
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• Dc 60o

RM gradient 130,000 rad/m2/mas
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RM gradients, epoch 1999.26at 5mas 310
rad/m2/masat 8 mas 86 rad/m2/mas

• T. Chen 2005
• Ph.D. dissertation

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RM gradients, epoch 1999.37at 5mas 356
rad/m2/masat 8 mas 189 rad/m2/mas
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RM gradients, epoch 1999.74at 5mas -286
rad/m2/masat 8 mas 297 rad/m2/mas
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RM gradients, epoch 2000.04at 5mas 230
rad/m2/masat 8 mas 300 rad/m2/mas
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The gradient of the gradient
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B vectors
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Conclusions

• SO IN CONCLUSION
• RM gradients are real
• They increase rapidly towards the core and vary
  on very short timescales
• The Faraday rotation is external to the jet, but
  very close to it
• This is a new way to see the direct interaction
  between the jet and its environment
• According to Amperes law, the jet must carry a
  current. We can measure it if we can disentangle
  the electron density and magnetic field.