Light curves from highly compact neutron stars with spot size effect
Light curves from highly compact neutron stars with spot size effect
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DOI：
10.1103/physrevd.101.063013
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发表时间：
2020-02
影响因子：
5
通讯作者：
H. Sotani
中科院分区：
文献类型：
--
作者：
H. Sotani
我们系统地研究了一颗密度非常高的慢转中子星上单个热点的光曲线，其中不存在所谓的不可见区域。特别是，我们采用了三种不同形状的热斑，并考虑了热斑对光曲线的有限尺寸效应。然后，我们发现，当小面积的热点穿过观察者的相反一侧时，通量会变亮，并且随着热点面积的减小，变亮的程度会变得更强。由于这种发亮只发生在热点的一部分穿过观测者的相反一侧时，如果观察到发亮，人们可以约束中子星的几何形状，即倾角、旋转轴与热点中心法矢的夹角以及热点的张开角。此外，通过计算光曲线中的这种亮化，可以知道有多少窄带热点和/或小面积斑点穿过观察者的相反侧。
We systematically examine light curves from a single hot spot on a slowly rotating neutron star with very high compactness, where the so-called invisible zone does not exist. In particular, we adopt three different shapes of hot spot and take into account the finite size effect of hot spot on the light curves. Then, we find that the brightening of flux occurs when the hot spot with small area crosses the opposite side to the observer, where the brightening becomes stronger as the area of hot spot decreases. Since this brightening happens only when a part of hot spot crosses the opposite side to the observer, one may constrain the neutron star geometry, i.e., the combination of an inclination angle, angle between the rotational axis and normal vector at the center of hot spot, and the opening angle of hot spot, if the brightening would be observed. In addition, by counting such a brightening in the light curves, one may know how many narrow bands of hot spot and/or spots with small area cross the opposite side to the observer.