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|Title:||Radio polarization properties of quasars and active galaxies at high redshifts||Authors:||Vernstrom, T.
Gaensler, B. M.
Farnes, J. S.
O'Sullivan, S. P.
|Issue Date:||2018||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||475||Issue:||2||First Page:||1736||Abstract:||We present the largest ever sample of radio polarization properties for z > 4 sources, with 14 sources having significant polarization detections. Using wide-band data from the Karl G. Jansky Very Large Array, we obtained the rest-frame total intensity and polarization properties of 37 radio sources, nine of which have spectroscopic redshifts in the range 1 ≤ z ≤ 1.4, with the other 28 having spectroscopic redshifts in the range 3.5 ≤ z ≤ 6.21. Fits are performed for the Stokes I and fractional polarization spectra, and Faraday rotation measures are derived using rotation measure synthesis and QU fitting. Using archival data of 476 polarized sources, we compare high-redshift (z > 3) source properties to a 15 GHz rest-frame luminosity matched sample of low-redshift (z < 3) sources to investigate if the polarization properties of radio sources at high redshifts are intrinsically different than those at low redshift. We find a mean of the rotation measure absolute values, corrected for Galactic rotation, of 50 ± 22 rad m<SUP>-2</SUP> for z > 3 sources and 57 ± 4 rad m<SUP>-2</SUP> for z < 3. Although there is some indication of lower intrinsic rotation measures at high-z possibly due to higher depolarization from the high-density environments, using several statistical tests we detect no significant difference between low- and high-redshift sources. Larger samples are necessary to determine any true physical difference.||URI:||http://hdl.handle.net/20.500.12386/28075||URL:||https://academic.oup.com/mnras/article/475/2/1736/4725060||ISSN:||0035-8711||DOI:||10.1093/mnras/stx3191||Bibcode ADS:||2018MNRAS.475.1736V||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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checked on Jan 17, 2021
checked on Jan 17, 2021
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