Bose Sukanta, Chakravarti Kabir, Rezzolla Luciano, Sathyaprakash B S, Takami Kentaro
Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007, India.
Department of Physics & Astronomy, Washington State University, 1245 Webster, Pullman, Washington 99164-2814, USA.
Phys Rev Lett. 2018 Jan 19;120(3):031102. doi: 10.1103/PhysRevLett.120.031102.
We show how gravitational-wave observations with advanced detectors of tens to several tens of neutron-star binaries can measure the neutron-star radius with an accuracy of several to a few percent, for mass and spatial distributions that are realistic, and with none of the sources located within 100 Mpc. We achieve such an accuracy by combining measurements of the total mass from the inspiral phase with those of the compactness from the postmerger oscillation frequencies. For estimating the measurement errors of these frequencies, we utilize analytical fits to postmerger numerical relativity waveforms in the time domain, obtained here for the first time, for four nuclear-physics equations of state and a couple of values for the mass. We further exploit quasiuniversal relations to derive errors in compactness from those frequencies. Measuring the average radius to well within 10% is possible for a sample of 100 binaries distributed uniformly in volume between 100 and 300 Mpc, so long as the equation of state is not too soft or the binaries are not too heavy. We also give error estimates for the Einstein Telescope.
我们展示了利用先进探测器对数十个到几十个中子星双星进行引力波观测，如何在源均不在100兆秒差距范围内且质量和空间分布符合实际的情况下，以百分之几的精度测量中子星半径。我们通过将来自旋进阶段的总质量测量值与来自合并后振荡频率的紧致度测量值相结合来达到这一精度。为了估计这些频率的测量误差，我们利用了首次在此获得的、针对四种核物理状态方程和几个质量值的时域合并后数值相对论波形的解析拟合。我们进一步利用准通用关系从这些频率推导出紧致度的误差。对于在100到300兆秒差距之间体积均匀分布的100个双星样本，只要状态方程不太软或双星不太重，将平均半径测量到10%以内是可能的。我们还给出了爱因斯坦望远镜的误差估计。
