Pulse profiles from a pulsar in scalar-tensor gravity
Pulse profiles from a pulsar in scalar-tensor gravity
复制标题
标量张量引力中脉冲星的脉冲轮廓
DOI：
10.1103/physrevd.96.104010
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发表时间：
2017
影响因子：
5
通讯作者：
Sotani Hajime
中科院分区：
文献类型：
--
作者：
柳漠;Nur Liyana Mohd Anuar;萩野浩一;有友嘉浩;太田雅久;上田 惟行;Masaaki Takahashi;MAGIC Collaboration;Sotani Hajime
本文在几种恒星模型中检验了引力标量张量理论中子星的脉冲剖面，在这些模型中，我们基于极帽模型假设中子星上存在对跖热点。然后，我们发现在标量张量引力下标化中子星的脉冲轮廓与广义相对论中几乎相同，即在没有标量场的情况下，如果两颗恒星的恒星紧度非常相似。也就是说，标量场的存在并不会直接改变中子星的脉冲轮廓，而即使在标量张量引力下，恒星的紧度也是决定脉冲形状的关键。此外，我们发现来自标度中子星的脉冲形状与广义相对论中相同质量中子星的脉冲形状或多或少相似，而脉冲剖面中最小振幅与最大振幅的比值强烈依赖于标量张量引力中的耦合常数，依赖于自转轴与磁轴之间的夹角以及自转轴与观测者方向之间的夹角。因此，利用对脉冲剖面的直接观测和对恒星质量的附加观测，可以提取出强场状态下引力理论的印记。
The pulse profile from a neutron star in scalar-tensor theory of gravity is examined for several stellar models, where we assume the existence of the antipodal hot spots on the neutron star based on the polar cap model. Then, we find that the pulse profile from the scalarized neutron star in scalar-tensor gravity is almost the same as that in general relativity, i.e., without a scalar field, if the stellar compactness of both stars is very similar. That is, the existence of the scalar field does not directly change the pulse profile from the neutron star, while the stellar compactness is crucial for determining the pulse shape even in the scalar-tensor gravity. Additionally, we find that the pulse shape from the scalarized neutron star is more or less similar to that from the neutron star with the same mass in general relativity, while the ratio of the minimum amplitude to the maximum amplitude in the pulse profile depends strongly on the coupling constant in scalar-tensor gravity, depending on the angle between the rotational and magnetic axes and the angle between the rotational axis and the direction to the observer. So, using the direct observation of the pulse profile together with the additional observation of the stellar mass, one may extract the imprint of the gravitational theory in strong field regime.