论文标题
中子恒星表面层的极化辐射转移
Polarized Radiation Transfer in Neutron Star Surface Layers
论文作者
论文摘要
在高度磁性恒星的高磁性表面位置的极化辐射转移的研究中,它对积聚X射线脉冲星,旋转驱动的脉冲星和磁铁的理解引起了极大的兴趣。本文探讨了对这些中子星类别的经典磁性汤姆森域中的散射传输。详细介绍了蒙特卡洛模拟为极化辐射转移的开发:它采用电场矢量形式主义来使实用性在线性,圆形和椭圆极化方面具有广度。该模拟可以应用于任何中子星形位置,并适应增生柱和磁层问题。强度和Stokes参数确定的代码验证以多种方式说明。向极性和赤道磁性位置提出了来自表面层的新兴极化信号的代表性结果,并在两个区域之间表现出对比鲜明的特征。这些特征对光子频率与回旋频率的比率也有很强的依赖性。提出了高不透明度结构域的极化特征,突出了STOKES参数的紧凑分析近似值和各向异性相对于局部场方向而言,对于扩展的频率范围。这些对于定义模拟平板几何形状深处的注入条件非常有用,从而加快了高度不透明恒星大气的发射信号的生成。在整个过程中都使用磁性汤森差异横截面的极化特性来解释结果。
The study of polarized radiation transfer in the highly-magnetized surface locales of neutron stars is of great interest to the understanding of accreting X-ray pulsars, rotation-powered pulsars and magnetars. This paper explores scattering transport in the classical magnetic Thomson domain that is of broad applicability to these neutron star classes. The development of a Monte Carlo simulation for the polarized radiative transfer is detailed: it employs an electric field vector formalism to enable a breadth of utility in relating linear, circular and elliptical polarizations. The simulation can be applied to any neutron star surface locale, and is adaptable to accretion column and magnetospheric problems. Validation of the code for both intensity and Stokes parameter determination is illustrated in a variety of ways. Representative results for emergent polarization signals from surface layers are presented for both polar and equatorial magnetic locales, exhibiting contrasting signatures between the two regions. There is also a strong dependence of these characteristics on the ratio of the frequency of a photon to the cyclotron frequency. Polarization signatures for high opacity domains are presented, highlighting compact analytic approximations for the Stokes parameters and anisotropy relative to the local field direction for an extended range of frequencies. These are very useful in defining injection conditions deep in the simulation slab geometries, expediting the generation of emission signals from highly opaque stellar atmospheres. The results are interpreted throughout using the polarization characteristics of the magnetic Thomson differential cross section.