Refractive Focusing by Interstellar Clouds and the Rapid Polarization Angle Swing in QSO 1150+812

Refractive Focusing by Interstellar Clouds and the Rapid Polarization Angle Swing in QSO 1150+812

Shan-Jie Qian;J.A. Zensus;T. P. Krichbaum;Xi-Zhen Zhang;L. Fuhrmann;G. Cimò;A. Kraus;T. Beckert;S. Britzen;A. Witzel

【期刊名称】《天文和天体物理学研究》 【年(卷),期】2006(006)001

【摘要】A very rapid polarization position angle swing of ～ 180° (with a time scale of ～6 hours) observed at 2cm in QSO 1150+812 (z = 1.25) was reported by Kochenov & Gabuzda. This very rare event is difficult to explain. We found a possible interpretation in the framework of a source model consisting of three polarized components, in which two compact polarized components are nearly simultaneously occulted by an interstellar cloud, with consequent focusing-defocusing effects. A specific plasma-lens model is proposed which can reasonably fit the polarized flux density curve with results derived for the two lensed components. Some physical parameters of the plasma-lens and the source components are estimated. The two compact polarized components are estimated to have brightness temperatures of ～ 6 × 1012 K.Thus a bulk relativistic motion with a Lorentz factor less than 10 is required to meet the inverse-Compton limit. 【总页数】14页(1-14)

【关键词】radio continuum: galaxies - galaxies: compact - polarization -