%0 Journal Article
%T Submillimeter polarization and variability of quasar PKS 1830¨C211
%A I. Marti-Vidal
%A S. Muller
%J -
%D 2019
%R 10.1051/0004-6361/201834036
%X Polarization from active galactic nuclei is interpreted as a signpost of the role of magnetic fields in the launch and collimation of their relativistic radio jets. Here, we report the detection of a clear polarization signal from ALMA observations of the gravitationally lensed quasar PKS 1830£¿211 at submillimeter wavelengths (Band 9, 650 GHz). Applying a differential-polarimetry technique to the two compact lensed images of the quasar, we estimate a fractional polarization of ¡«5% for one lensed image, while the other appears nearly unpolarized, which implies that the polarization activity varies on a timescale of a few weeks. With additional ALMA Band 7 and 8 (between 300¨C500 GHz) concomitant data, we constrain a Faraday rotation of a few 10<sup>5<sup/> rad m<sup>£¿2<sup/>. We also observe flux-density variability of £¿10% within one hour in Band 9. This work illustrates that a differential analysis can extract high-accuracy information (flux-density ratio and polarimetry) free of calibration issues from resolved sources in the submillimeter domain
%U https://www.aanda.org/articles/aa/full_html/2019/01/aa34036-18/aa34036-18.html