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arXiv 2003.10391astro-ph.HEgr-qc
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越重越好:如何限制高质量中子星合并的质量比和自旋

The heavier the better: how to constrain mass ratios and spins of high-mass neutron-star mergers

Elias R. Most, Lukas R. Weih, Luciano Rezzolla

摘要:

第一个双中子星合并事件,GW 170817,以及它明亮的电磁对应物提供了大量的信息。相比之下,第二个事件,GW 190425,与$M_{\rm tot}=3.4^{+0.3}_{-0.1}\,M_{\odot}$和缺乏电磁对应物,几乎没有提高我们对中子星物理学的理解。虽然GW 190425与合并导致迅速坍缩成黑洞和几乎没有喷射物质为对应物提供动力的情况是兼容的,但确定双星的质量比和有效自旋$\tildeχ$仍然很困难。这是因为引力波形还不能很好地约束双星的分量自旋。然而,由于GW 190425的质量明显大于非旋转中子星的最大质量$M_{_{\rm TOV}}$,质量比$q$不能太小,因为较重的恒星在引力上不稳定。利用普适关系和大量的状态方程,我们提供了在$(\tildeχ,q)$平面上的限制GW190425,即:$q_{\rm min} \geq 0.38$和$ \tildeχ_{\rm max}\leq 0.20$,假设$M_\mathrm{tot} \simeq 3.4\, M_\odot$。最后,我们展示了未来的观测高质量的二进制可以提供一个下限的$M_{_{\rm TOV}}$。

英文摘要:

The first binary neutron-star merger event, GW170817, and its bright electromagnetic counterpart have provided a remarkable amount of information. By contrast, the second event, GW190425, with $M_{\rm tot}=3.4^{+0.3}_{-0.1}\,M_{\odot}$ and the lack of an electromagnetic counterpart, has hardly improved our understanding of neutron-star physics. While GW190425 is compatible with a scenario in which the merger has lead to a prompt collapse to a black hole and little ejected matter to power a counterpart, determining the mass ratio and the effective spin $\tildeχ$ of the binary remains difficult. This is because gravitational waveforms cannot yet well constrain the component spins of the binary. However, since the mass of GW190425 is significantly larger than the maximum mass for nonrotating neutron stars, $M_{_{\rm TOV}}$, the mass ratio $q$ cannot be too small, as the heavier star would not be gravitationally stable. Making use of universal relations and a large number of equations of state, we provide limits in the $(\tildeχ,q)$ plane for GW190425, namely: $q_{\rm min} \geq 0.38$ and $ \tildeχ_{\rm max}\leq 0.20$, assuming $M_\mathrm{tot} \simeq 3.4\, M_\odot$. Finally, we show how future observations of high-mass binaries can provide a lower bound on $M_{_{\rm TOV}}$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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