We investigate the properties of postmerger remnants of binary neutron star mergers in the framework of Damour–Esposito-Farese-type scalar-tensor theory of gravity with a massive scalar field by numerical relativity simulation. It is found that the threshold mass for prompt collapse is raised in the presence of the excited scalar field. Our simulation results also suggest the existence of a long-lived 𝜙 mode in hypermassive neutron stars due to the presence of the massive scalar field that enhances the quasiradial oscillation in the remnant. We investigate the descalarization condition in hypermassive neutron stars and discover a distinctive signature in postmerger gravitational waves.

中文翻译：

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大质量标量张量理论中的双中子星合并：合并后残余的性质


我们通过数值相对论模拟，在 Damour-Esposito-Fareese 型引力标量理论的框架内研究了双中子星合并后残余物的性质。发现在激发标量场存在的情况下，迅速坍缩的阈值质量会提高。我们的模拟结果还表明，超大质量中子星中存在长寿命的φ模式，因为大质量标量场的存在增强了残余物中的准径向振荡。我们研究了超大质量中子星的脱尺度条件，并在合并后的引力波中发现了独特的特征。