[30.12] Helical Magnetic Fields and Faraday Rotation Measure Gradients in 3C 273

AAS 206th Meeting, 29 May - 2 June 2005
Session 30 Relativistic Jets
Topical Session, Wednesday, 8:30-10:00am, 10:45am-12:30pm, 2:30-4:00pm, 4:15-6:00pm, June 1, 2005, 102 B

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[30.12] Helical Magnetic Fields and Faraday Rotation Measure Gradients in 3C 273

R. T. Zavala (US Naval Observatory), G. B. Taylor (NRAO & KIPAC)

Using high frequency (12-22 GHz) VLBA observations we confirm the existence of a Faraday rotation measure gradient transverse to the jet axis of the quasar 3C 273. This transverse rotation measure gradient is expected if a helical magnetic field wraps around the jet. The overall order to the magnetic field in the inner projected 40 parsecs is consistent with a helical field. However, we find an unexpected increase in fractional polarization along the rotation measure gradient. This high fractional polarization observed along the RM gradient rules out internal Faraday rotation, but is not readily explained by a helical field. If a helical magnetic field causes the observed rotation measure gradient then the synchrotron emitting electrons must be separate from the helical field region.

The author(s) of this abstract have provided an email address for comments about the abstract: bzavala@nofs.navy.mil

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