1、偏振v电矢量振动方向对于传播方向的不对称性叫做偏振，它是横波区别于其他纵波的一个最明显的标志。偏振光的描述方法v经典方法v斯托克斯参数法 I：总强度 (Q2+U2)1/2:线偏振成分的强度 V：圆偏振成分的强度 tan-1(U/Q)/2:线偏振位置角斯托克斯参数的性质v自然光：I，0，0，0v强度为I的自然光可看作是两束强度相等、不相干的反向偏振光I/2,Q,U,V和I/2,-Q,-U,-V的混合。v任意偏振光I,Q,U,V可以分为一束自然光I-(Q2+U2+V2)1/2,0,0,0和一束完全椭圆偏振光(Q2+U2+V2)1/2,Q,U,V,或者一束自然光I-(Q2+U2+V2)1/2-|V|
2、,0,0,0和一束完全线偏振光(Q2+U2+V2)1/2,Q,U,0以及一束完全圆偏振光|V|,0,0,V。Polarization measurementsvRadio telescopes usually take measurements in two orthogonal polarizations.vFor a dual-linear feed vFor a dual-circular feed 法拉第旋转效应v=RM2脉冲星的周期分布Millisecond pulsarsNormal pulsarsP-Pdot diagram Harding 2013Duty cycle(W/P)
3、Kramer et al.1998光速圆柱半径Pulsar emission beamGil et al.1984Opening angle Kramer et al.1998InterpulsevThe secondary pulses separated by about 180from the main pulse.vThe main pulse and interpulse originate from oppsite magnetic poles.vWhile only about 2%of all normal pulsars are known to exhibit interp
4、ulses or pre-or postcursors,about 36%of all Galactic MSPs known either emit a post or precursor or exhibit an interpulse.Kramer et al.1998Rotating Vector Model（Radhakrishnan&Cooke 1969）Von Hoensbroech&Xilouris 1997Polarization similarity Han et al.2009 Ord et al.2004Parkes Pulsar Timing Array projec
5、tPPTA脉冲星的偏振轮廓vYan et al.2011aPA variations with timevLong-term changes in pulsar PAs can result from changes in the polarization of the emitted radiation or from changes in the RM along the path.PA=RM2vIntrinsic PA changes could result from precession of the pulsar spin axis or changes in the magnet
6、ic configuration of the star.vRM changes can occur as the path to the pulsar traverses different regions of the interstellar medium(ISM)or in certain changes the Earths ionosphere.Vela pulsar(PSR B0833-45)vdiscovered in 1968,89msvnear the center of the Vela nebulavHamilton et al.1985 双脉冲星系统 J0737-30
7、39vdiscovered in 2003,22.7ms,2.77sva laboratory for strong-field gravity and plasma physics Yuen et al.2012PA variations for PPTA pulsars Yan et al.2011b总结v毫秒脉冲星的偏振性质和普通脉冲星是相似的，说明两类脉冲星基本的辐射机制是相同的v然而毫秒脉冲星的偏振位置角和轮廓形状比普通脉冲星复杂，说明毫秒脉冲星的辐射区结构更复杂v经过电离层修正以后，PPTA毫秒脉冲星的偏振位置角没有显著的随时间长期变化的趋势，说明不仅PPTA脉冲星发出的偏振辐射本身是稳定的，并且视线穿过的星际介质贡献的RM的长期净变化也非常小Thanks for your attention!
