Quasi-equilibrium sequences of binary neutron stars undergoing dynamical scalarization
Quasi-equilibrium sequences of binary neutron stars undergoing dynamical scalarization
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经历动力学标量化的双中子星的准平衡序列
DOI：
10.1103/physrevd.91.024033
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发表时间：
2015
影响因子：
5
通讯作者：
and A. Buonanno
中科院分区：
文献类型：
--
作者：
K. Taniguchi;M. Shibata;and A. Buonanno
我们计算准平衡序列的等质量，无旋双星的标量张量引力理论，承认动态标量化。我们模拟中子星与现实的状态方程（特别是通过分段多方状态方程）。使用这些准平衡序列，我们计算二进制的标量电荷和结合能与轨道角频率。我们发现，结合能的绝对值小于广义相对论，不同的是在最高频率的情况下考虑。我们使用新计算的结合能和平衡方程来估计的引力波（GW）周期的数量在绝热，准圆形的螺旋上升阶段的序列，这是最后一个稳定的轨道或质量脱落点，这取决于哪一个先来的结束。我们发现，根据标量张量参数，GW周期的数量可以大大小于广义相对论。特别地，我们得到，当动力学标量化集在GW频率附近时，仅包含标量张量结合能会导致GW周期从到序列（）的末尾减少。(The在广义相对论中，从到序列结束的GW周期数是。）我们估计，当标量张量能流也包括在GW周期的减少成为。非常有趣的是，动力学标量化可以产生的GW周期的数量的差异相对于广义相对论的点粒子的情况下，这是远远大于由于潮汐相互作用的影响，这是对只有几个GW周期的顺序。这些结果进一步澄清和证实了最近的研究，已经发展的双中子星无论是在完全数值相对论或后牛顿理论，并指出发展精确的标量张量理论波形的系统组成的强自引力的对象，如双中子星的重要性。
We calculate quasiequilibrium sequences of equal-mass, irrotational binary neutron stars in a scalar-tensor theory of gravity that admits dynamical scalarization. We model neutron stars with realistic equations of state (notably through piecewise polytropic equations of state). Using these quasiequilibrium sequences we compute the binary’s scalar charge and binding energy versus orbital angular frequency. We find that the absolute value of the binding energy is smaller than in general relativity, differing at most byat high frequencies for the cases considered. We use the newly computed binding energy and the balance equation to estimate the number of gravitational-wave (GW) cycles during the adiabatic, quasicircular inspiral stage up to the end of the sequence, which is the last stable orbit or the mass-shedding point, depending on which comes first. We find that, depending on the scalar-tensor parameters, the number of GW cycles can be substantially smaller than in general relativity. In particular, we obtain that when dynamical scalarization sets in around a GW frequency of, the sole inclusion of the scalar-tensor binding energy causes a reduction of GW cycles fromup to the end of the sequence () ofwith respect to the general-relativity case. (The number of GW cycles fromto the end of the sequence in general relativity is.) We estimate that when the scalar-tensor energy flux is also included the reduction in GW cycles becomes of. Quite interestingly, dynamical scalarization can produce a difference in the number of GW cycles with respect to the general-relativity point-particle case that is much larger than the effect due to tidal interactions, which is on the order of only a few GW cycles. These results further clarify and confirm recent studies that have evolved binary neutron stars either in full numerical relativity or in post-Newtonian theory, and point out the importance of developing accurate scalar-tensor-theory waveforms for systems composed of strongly self-gravitating objects, such as binary neutron stars.