AI 中文总结
研究比较黑洞阈值附近无扭转轴对称引力波的三个独立数值代码，关注各代码优缺点，研究近阈值坍缩特征，构建参考坐标辅助比较，演化时间不对称波初始数据，比较表观视界，三个代码结果一致。
AI 中文摘要
轴对称真空引力中黑洞形成的阈值比预期的更为复杂，但随着近期进展，独立代码和方法之间正在形成共识。基于早期工作，我们进一步详细比较了三个独立数值代码（bamps、prague和sphGR代码），特别关注每个代码的相对优缺点，并首次研究了真空引力波近阈值坍缩的各种特征。特别是，我们观察到曲率标量中出现的准普遍强场特征。关注对称轴上的几何特征，我们构建参考坐标以辅助强场数据的比较。我们首次在bamps代码中演化时间不对称波初始数据。在当前方法允许的范围内，我们比较表观视界，并试图确定在这些强场和高度动态时空的分类中造成困难的原因。在所有情况下，三个代码的结果都非常一致。
英文摘要
The threshold of black hole formation in axisymmetric vacuum gravity is proving to be more complicated than had been anticipated but, following recent advances, a consensus between independent codes and methods is emerging. Building on earlier work we provide further details of a comparison between three independent numerical codes (the bamps, prague, and sphGR codes), paying special attention to the relative strengths and weaknesses of each and examining various features of near-threshold collapse of vacuum gravitational waves for the first time. In particular, we observe quasi-universal strong-field features appearing in curvature scalars. Focusing on geometric features on the symmetry axis, we construct reference coordinates to aid the comparison of strong-field data. We evolve, for the first time, time-asymmetric wave initial data within the bamps code. To the extent possible with current methods we compare apparent horizons and attempt to determine what causes difficulties in the classification of these strong-field and highly dynamical spacetimes. In all cases the results from the three codes agree very well.
Comments17 pages, 11 figures
