Constructing binary neutron star initial data with high spins, high compactnesses, and high mass ratios
Constructing binary neutron star initial data with high spins, high compactnesses, and high mass ratios
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DOI：
10.1103/physrevd.100.124046
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发表时间：
2019-10
影响因子：
5
通讯作者：
W. Tichy;A. Rashti;T. Dietrich;R. Dudi;B. Brügmann
中科院分区：
文献类型：
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作者：
W. Tichy;A. Rashti;T. Dietrich;R. Dudi;B. Brügmann
为各种二元参数构建准确且一致的初始数据是紧凑二元合并数值相对论模拟的关键因素。在本文中，我们提出了伪谱 SGRID 代码的升级，它使我们能够访问双中子星参数空间的更大区域。作为原理证明，我们基于使用新代码版本计算的初始配置提出了一组选定的首次模拟。特别是，我们模拟了两颗接近解体自旋的毫秒脉冲星、质量约为所用状态方程最大支持质量 $98\%$ 的高度致密中子星，以及质量比甚至超出总体合成模型预测范围 ($q = 2.03$) 的不等质量系统。所讨论的代码扩展将帮助我们模拟以前未探索的二进制配置。这是构建和测试新的引力波近似值以及解释即将到来的双中子星合并观测的必要步骤。当我们构建初始数据时，必须指定各种参数，例如每颗恒星的旋转参数。其中一些参数没有直接的物理意义，这使得与其他方法或模型进行比较变得困难。为了促进这一点，我们对每颗恒星的初始自旋、动量、质量和质心进行了简单的估计。
The construction of accurate and consistent initial data for various binary parameters is a critical ingredient for numerical relativity simulations of the compact binary coalescence. In this article, we present an upgrade of the pseudospectral SGRID code, which enables us to access even larger regions of the binary neutron star parameter space. As a proof of principle, we present a selected set of first simulations based on initial configurations computed with the new code version. In particular, we simulate two millisecond pulsars close to their breakup spin, highly compact neutron stars with masses at about $98\%$ of the maximum supported mass of the employed equation of state, and an unequal mass systems with mass ratios even outside the range predicted by population synthesis models ($q = 2.03$). The discussed code extension will help us to simulate previously unexplored binary configurations. This is a necessary step to construct and test new gravitational wave approximants and to interpret upcoming binary neutron star merger observations. When we construct initial data, one has to specify various parameters, such as a rotation parameter for each star. Some of these parameters do not have direct physical meaning, which makes comparisons with other methods or models difficult. To facilitate this, we introduce simple estimates for the initial spin, momentum, mass, and center of mass of each individual star.