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arXiv 1709.03311gr-qc
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大质量双引力中的慢转中子星

Slowly-Rotating Neutron Stars in Massive Bigravity

Andrew Sullivan, Nicolas Yunes

摘要:

我们研究在无鬼的大质量双引力中缓慢旋转的中子星。该理论通过引入第二个辅助但动态的张量场来修改广义相对论,该张量场通过非线性相互作用通过物理度量张量耦合到物质。我们扩展的场方程的线性顺序在缓慢的旋转和数值构造的解决方案,在内部和外部的恒星与一组现实的状态方程。我们计算的物理质量函数相对于观察者半径,并发现,不像在广义相对论中,这个功能并不保持恒定的恒星外,而是,它渐近到一个常数的距离,从表面,其大小是由引力常量的比例控制。物理质量函数和辅助质量函数渐近线为常数的类万施泰因半径由引力子质量标度参数控制,在此半径之外,双引力修正被抑制。我们还计算了框架拖曳度规函数,发现在整个耦合参数范围内,双引力修正通常很小。最后,我们计算的质量半径和转动惯量的质量关系的耦合参数范围很广,发现引力子质量标度参数和引力常量的比例都引入了大的修改。这些结果可以用来放置未来的约束与孤立和双中子星的电磁和引力波观测的双引力。

英文摘要:

We study slowly-rotating neutron stars in ghost-free massive bigravity. This theory modifies General Relativity by introducing a second, auxiliary but dynamical tensor field that couples to matter through the physical metric tensor through non-linear interactions. We expand the field equations to linear order in slow rotation and numerically construct solutions in the interior and exterior of the star with a set of realistic equations of state. We calculate the physical mass function with respect to observer radius and find that, unlike in General Relativity, this function does not remain constant outside the star; rather, it asymptotes to a constant a distance away from the surface, whose magnitude is controlled by the ratio of gravitational constants. The Vainshtein-like radius at which the physical and auxiliary mass functions asymptote to a constant is controlled by the graviton mass scaling parameter, and outside this radius, bigravity modifications are suppressed. We also calculate the frame-dragging metric function and find that bigravity modifications are typically small in the entire range of coupling parameters explored. We finally calculate both the mass-radius and the moment of inertia-mass relations for a wide range of coupling parameters and find that both the graviton mass scaling parameter and the ratio of the gravitational constants introduce large modifications to both. These results could be used to place future constraints on bigravity with electromagnetic and gravitational-wave observations of isolated and binary neutron stars.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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