Testing the Correlation between Bending Angle and Polarization Properties of Bent Radio Galaxies

The Astrophysical Journal, vol. 996, pp. 81

Abstract

Abstract The bending of radio galaxies in galaxy clusters is expected to be caused by interactions with the local environment. The physical processes responsible for jet bending, and their influence on the polarization properties of radio galaxies, remain poorly understood, leading to the question of whether the jet properties in bent radio galaxies differ from those in linear radio galaxies. Using a sample of 24 polarized bent radio galaxies, observed with the Karl G. Jansky Very Large Array at 1–2 GHz, we test for correlation of the bending angle with polarization parameters, measuring Faraday rotation, intrinsic fractional polarization, and Faraday rotation dispersion, used here as a measure of turbulence along the line of sight. We find no statistically significant correlations. At the spatial resolution of our dataset (3–46 kpc, median = 18.4 kpc), our results indicate that we are primarily probing larger-scale intracluster medium effects not related to bending angle. The absence of a statistically significant correlation suggests that bent radio galaxies are reliable probes of intracluster magnetic fields, because their intrinsic properties do not appear to introduce systematic biases into measured polarization parameters. We do detect a preference for source magnetic field vectors to align with the direction of jet bending. Finally, we estimate that the POSSUM and Square Kilometre Array surveys will contain ≳300 and ≳1000 polarized radio galaxies, respectively, providing large future samples with a range of bending angles and similar redshift distribution and number of beams per source as in our sample, enabling our results to be tested with greater statistical power.

Authors 5

1. Shannon Vanderwoude corresponding

   University of Toronto

   Affiliation as printed

   David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4, Canada; shannon.vanderwoude@gmail.com

   Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4, Canada

2. E. Osinga Aachen Leiden Observatory

   Leiden University · University of Toronto · Leiden Observatory

   Affiliation as printed

   Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4, Canada

   Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, The Netherlands

3. B. M. Gaensler

   University of California, Santa Cruz · University of Toronto

   Affiliation as printed

   David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4, Canada; shannon.vanderwoude@gmail.com

   Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064, USA

   Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4, Canada

4. J. L. West

   Herzberg Institute of Astrophysics · National Research Council Canada

   Affiliation as printed

   Dominion Radio Astrophysical Observatory, Herzberg Astronomy and Astrophysics, National Research Council Canada, P.O. Box 248, Penticton, BC V2A 6J9, Canada

5. Reinout J. van Weeren corresponding Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, The Netherlands