Gravitational waves and mass ejecta from binary neutron star mergers: Effect of the mass-ratio
Gravitational waves and mass ejecta from binary neutron star mergers: Effect of the mass-ratio
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DOI：
10.1103/physrevd.95.024029
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发表时间：
2016-07
影响因子：
5
通讯作者：
T. Dietrich;M. Ujevic;W. Tichy;S. Bernuzzi;B. Bruegmann
中科院分区：
文献类型：
--
作者：
T. Dietrich;M. Ujevic;W. Tichy;S. Bernuzzi;B. Bruegmann
我们提出了新的（$3+1$）双中子星（BNS）合并的二维数值相对论模拟，其中考虑了NS自旋。对于等质量和不等质量bss以及两个状态方程，我们考虑了不同的自旋构型，与轨道角动量对齐或反对齐。所有模拟均采用匀速方法下的准平衡圆初始数据，即与爱因斯坦方程和流体动力平衡相一致。我们研究了NS旋转对能量学、引力波（GWs）以及与动态质量抛射相关的可能的电磁（EM）发射的影响。对于$\ensuremath{\chi}\ensuremath{\sim}0.1$的无因次自旋大小，我们发现自旋-轨道相互作用和自旋诱导的四极变形都会影响后期启发合并动力学。然而，后者是由有限尺寸效应主导的。自旋（潮汐）效应对GW相位差的贡献高达$\ensuremath{\sim}5$（20）弧度，这是在最后8个轨道合并期间积累的。同样，合并后的残体坍缩时间和GW谱图也受到NSs旋转的影响。动态抛射中的自旋效应在非等质量系统中被清楚地观察到，其中物质抛射起源于伴星的潮汐尾。因此，千新星和其他EM对应物受到自旋的影响。我们发现，与轨道角动量相对应的自旋比与轨道角动量相反的自旋更亮，其光度高达2倍。
We present new ($3+1$)-dimensional numerical relativity simulations of the binary neutron star (BNS) mergers that take into account the NS spins. We consider different spin configurations, aligned or antialigned to the orbital angular momentum, for equal- and unequal-mass BNSs and for two equations of state. All the simulations employ quasiequilibrium circular initial data in the constant rotational velocity approach, i.e. they are consistent with the Einstein equations and in hydrodynamical equilibrium. We study the NS rotation effect on the energetics, the gravitational waves (GWs) and on the possible electromagnetic (EM) emission associated to dynamical mass ejecta. For dimensionless spin magnitudes of $\ensuremath{\chi}\ensuremath{\sim}0.1$ we find that both spin-orbit interactions and spin-induced quadrupole deformations affect the late-inspiral merger dynamics. The latter is, however, dominated by finite-size effects. Spin (tidal) effects contribute to GW phase differences up to $\ensuremath{\sim}5$ (20) radians accumulated during the last eight orbits to merger. Similarly, after merger the collapse time of the remnant and the GW spectrogram are affected by the NSs rotation. Spin effects in dynamical ejecta are clearly observed in unequal-mass systems in which mass ejection originates from the tidal tail of the companion. Consequently kilonovae and other EM counterparts are affected by spins. We find that spin aligned to the orbital angular momentum leads to brighter EM counterparts than antialigned spin with luminosities up to a factor of 2 higher.