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arXiv · 1303.2847

Using head-tail galaxies to constrain the intracluster magnetic field: an in-depth study of PKS J0334-3900

Luke Pratley·Melanie Johnston-Hollitt·Siamak Dehghan·Ming Sun
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Abstract

We present a multi-wavelength study of the radio galaxy PKS J0334-3900 at the centre of Abell 3135. The spectro-polarimetric radio observations are combined with spectroscopic optical and X-ray data to illustrate the use of Head-Tail radio galaxies to reveal properties of the intracluster medium. ATCA observations at 1.4, 2.5, 4.6 & 8.6 GHz are presented with a detailed analysis of the morphology and spectral indices giving physical parameters to constrain the dynamical history of the galaxy. Using these constraints we produce a simulation of PKS J0334-3900. We find that this Head-Tail morphology can be induced via a combination of orbital motion due to a binary companion and relative motion through the ICM. New Chandra images of A3135 are presented from which we obtain a cluster electron density of n_(e,0) = (1.06 +/- 0.11 x 10^(-3) cm^(-3), a global temperature of 2.4 ^(+0.51)_(-0.38) keV and a lower limit to the radio jet power of PKS J0334-3900 of 1.6 x 10^(44) erg/s. A new redshift analysis of the cluster from available spectroscopic data shows A3135 to be comprised of galaxies with 0.058 < z < 0.066 and gives a new mean cluster redshift of 0.06228 +/- 0.00015. We also uncovered a background subgroup between 0.066 < z < 0.070. Stokes Q and U data of Abell 3135 were used to obtain rotation measure values along the line of sight to PKS J0334-3900. Using our simulation we are able to infer the distance between the jets to be 154 +/- 16 kpc, which when combined with the difference in rotation measure between the jets provides a novel new way to estimate the average magnetic field within a cluster. A lower limit to the cluster B-field was calculated to be 0.09 +/- 0.03 micro Gauss. We show observations of Head-Tail galaxies can be used to infer information on the cluster environment, showing them to be an important class of objects in next generation all sky surveys.

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Luke Pratley, Melanie Johnston-Hollitt, Siamak Dehghan, Ming Sun. 2013-04-05. Using head-tail galaxies to constrain the intracluster magnetic field: an in-depth study of PKS J0334-3900. https://doi.org/10.1093/mnras%2Fstt448

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