论文标题
使用拉格朗日数值相对论代码sphincs_bssn模拟中子星星合并
Simulating neutron star mergers with the Lagrangian Numerical Relativity code SPHINCS_BSSN
论文作者
论文摘要
我们介绍了第一个使用新开发的数值相对论代码SPHINCS_BSSN执行的中子星合并模拟。该代码使用BSSN公式在网格上演变，但根据一般偏见的平滑粒子流体动力学（SPH），通过拉格朗日颗粒进化物质。与其他数值相对论代码相比，我们的代码包含许多新的方法论元素。这里的主要重点是引入模型中子星星合并的新元素。其中包括a）时空网格的细化（固定时间），b）粒子映射算法和c）通过最近开发的“人工压力法”构造二进制系统的SPH初始数据的新型方法。后一种方法利用了库Lorene生成的光谱初始数据，并以一种称为SPHINCS_ID的新代码实现。虽然我们的主要重点是引入这些新的方法论元素并记录SPHINCS_BSSN的当前状态，但我们还显示了使用“软”（$γ= 2.00 $）和“ hiff”（$γ= 2.75 $）的状态的一组中子星星合并模拟。
We present the first neutron star merger simulations performed with the newly developed Numerical Relativity code SPHINCS_BSSN. This code evolves the spacetime on a mesh using the BSSN formulation, but matter is evolved via Lagrangian particles according to a high-accuracy version of general-relativistic Smooth Particle Hydrodynamics (SPH). Our code contains a number of new methodological elements compared to other Numerical Relativity codes. The main focus here is on the new elements that were introduced to model neutron star mergers. These include a) a refinement (fixed in time) of the spacetime-mesh, b) corresponding changes in the particle--mesh mapping algorithm and c) a novel way to construct SPH initial data for binary systems via the recently developed "Artificial Pressure Method." This latter method makes use of the spectral initial data produced by the library LORENE, and is implemented in a new code called SPHINCS_ID. While our main focus is on introducing these new methodological elements and documenting the current status of SPHINCS_BSSN, we also show as a first application a set of neutron star merger simulations employing "soft" ($Γ=2.00$) and "stiff" ($Γ=2.75$) polytropic equations of state.
