Revisiting the Lower Bound on Tidal Deformability Derived by AT 2017gfo
Revisiting the Lower Bound on Tidal Deformability Derived by AT 2017gfo
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DOI：
10.3847/2041-8213/ab1e45
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
K. Kiuchi;K. Kyutoku;M. Shibata;K. Taniguchi
中科院分区：
文献类型：
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作者：
K. Kiuchi;K. Kyutoku;M. Shibata;K. Taniguchi
我们重新审视了由发光kilonova/macronova，AT 2017 gfo，由数值相对论模拟的模型，是一致的引力波从二进制中子星星合并GW 170817的潮汐变形的下限。与文献中的说法相反，我们发现，只要像以前的工作那样假设从残骸中有适度的质量喷射，AT 2017 gfo的亮度就可以解释。原因是中子星星的最大质量与典型质量为1.4 M的中子星的潮汐变形能力没有很强的相关性。如果最大质量是如此之大，以至于双星在合并后不会立即坍缩成黑洞，那么喷出物的质量可以足够大，而不管双星的潮汐变形能力如何。我们提出的模型的二进制合并与下降到242，满足要求的喷出物的质量从光度的AT 2017 gfo。我们进一步发现，AT 2017 gfo的亮度可以用合并后没有反弹的模型来解释。我们的结论是，AT 2017 gfo的光度是不是很有用的约束的双潮汐变形。准确估计的质量比将是必要的，以建立一个下限使用电磁对应的未来。我们还警告说，合并模拟，采用有限的一类列表状态方程可能会严重偏见，由于缺乏一般性。
We revisit the lower bound on binary tidal deformability imposed by a luminous kilonova/macronova, AT 2017gfo, by numerical-relativity simulations of models that are consistent with gravitational waves from the binary neutron star merger GW170817. Contrary to the claim made in the literature, we find that binaries with can explain the luminosity of AT 2017gfo, as long as moderate mass ejection from the remnant is assumed as had been done in previous work. The reason is that the maximum mass of a neutron star is not strongly correlated with the tidal deformability of neutron stars with a typical mass of ≈1.4 M⊙. If the maximum mass is so large that the binary does not collapse into a black hole immediately after merger, the mass of the ejecta can be sufficiently large irrespective of the binary tidal deformability. We present models of binary mergers with down to 242 that satisfy the requirement on the mass of the ejecta from the luminosity of AT 2017gfo. We further find that the luminosity of AT 2017gfo could be explained by models that do not experience bounce after merger. We conclude that the luminosity of AT 2017gfo is not very useful for constraining the binary tidal deformability. Accurate estimation of the mass ratio will be necessary to establish a lower bound using electromagnetic counterparts in the future. We also caution that merger simulations that employ a limited class of tabulated equations of state could be severely biased due to the lack of generality.