Systematical study of pulsar light curves with special relativistic effects
Systematical study of pulsar light curves with special relativistic effects
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具有特殊相对论效应的脉冲星光变曲线的系统研究
DOI：
10.1103/physrevd.98.103019
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发表时间：
2018
影响因子：
5
通讯作者：
Miyamoto Umpei
中科院分区：
文献类型：
--
作者：
Sotani Hajime;Miyamoto Umpei
我们系统地研究了脉冲星的光变曲线，并考虑了特殊相对论效应，即，由于中子星的快速自旋而产生的多普勒因子，以及时间延迟，时间延迟来自于取决于斑点位置的旅行时间的差异。为此，首先，我们推导出静态球对称时空的基本方程和度规的一般表达式，其中为了简单起见，我们采用与磁极帽模型相关的对跖点的点状近似。然后，我们从广义相对论中的中子星模型出发，计算了不同的自转轴与磁轴夹角以及倾角下的光变曲线。结果表明，与慢转恒星模型不同，快转恒星模型的光变曲线不仅依赖于恒星的致密性，还依赖于恒星的半径。我们还发现光变曲线的振幅随着恒星半径的增大和恒星致密度的减小而增大。因此，通过仔细观察旋转中子星星的光变曲线，如果它旋转得足够快，人们可以确定恒星的致密性和恒星的半径。
We systematically study pulsar light curves, taking into account the special relativistic effect, i.e., the Doppler factor due to the fast spin of the neutron stars, together with the time delay, which comes from the difference of the travel times depending on the position of the spots. For this purpose, first, we derive the basic equations with the general expression of the metric for the static, spherically symmetric spacetime, in which for simplicity we adopt the pointlike spot approximation for the antipodal spots associated with the magnetic polar cap model. Then, we calculate the light curves from the neutron-star models in general relativity, with various angles between rotational and magnetic axes and the inclination angle. As a result, unlike the case for a slowly rotating stellar model, we find that the light curve from a fast rotating stellar model depends not only the stellar compactness but also the stellar radius. We also find that the amplitude of the light curve becomes larger as the stellar radius increases and as the stellar compactness decreases. Thus, via careful observations of the light curves from the rotating neutron star, one would determine the stellar compactness together with the stellar radius, if it rotates fast enough.