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Rotation measures in AGN jets seen by VLA at 21 cm to 6 mm

Published online by Cambridge University Press:  24 March 2015

Evgeniya V. Kravchenko ,
William D. Cotton  and
Yuri Y. Kovalev
Evgeniya V. Kravchenko
Affiliation:
Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia email: evk@asc.rssi.ru
William D. Cotton
Affiliation:
National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475, USA
Yuri Y. Kovalev
Affiliation:
Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia email: evk@asc.rssi.ru
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Abstract

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We present Faraday rotation measure (RM) properties of seven active galactic nuclei (AGN), observed with the NRAO VLA at three epochs in 2012-2014. Data was taken at 1.4, 2.2, 5.0, 8.2, 15.4, 22.4, 33.5 and 43.1 GHz quasi simultaneously in full polarization mode. For the first time RMs were calculated in a range of wavelengths covering more than one order of magnitude: from 21 cm up to 6 mm. We measured RM for each source and showed a tendency to increase its value toward high frequencies according to the law |RM|~νa with a = 1.6±0.1. For 0710+439, we observed an increase over the frequency range of 4 orders of magnitude and measured one of the highest RM ever, (−89±1)⋅103 rad/m2. Analysis of different epochs shows variations of the value and the sign of RM on short and long time-scales. This may be caused by changing physical conditions in the compact regions of the AGN jets, e.g., strength of magnetic field, particle density and so on.

Keywords

galaxies: activenucleijetsmagnetic fields
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 10 , Issue S313: Extragalactic jets from every angle , September 2014 , pp. 128 - 132
Copyright
Copyright © International Astronomical Union 2015 

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