Properties of Neutrino-driven Ejecta from the Remnant of a Binary Neutron Star Merger: Pure Radiation Hydrodynamics Case
Properties of Neutrino-driven Ejecta from the Remnant of a Binary Neutron Star Merger: Pure Radiation Hydrodynamics Case
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DOI：
10.3847/1538-4357/aa8039
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发表时间：
2017-03
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影响因子：
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通讯作者：
S. Fujibayashi;Yuichiro Sekiguchi;K. Kiuchi;M. Shibata
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文献类型：
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作者：
S. Fujibayashi;Yuichiro Sekiguchi;K. Kiuchi;M. Shibata
我们对双中子星合并后形成的残骸进行了广义相对论的、长期的、轴对称的中微子辐射流体动力学模拟，该残骸由一颗大质量中子星和环绕它的环面组成。作为初始条件，我们采用了双中子星合并的三维数值相对论模拟结果。我们研究了中微子驱动抛射的性质。由于对湮灭加热，中微子驱动的抛射动力学得到了显著的改变。抛射物的动能大约是没有对湮灭加热时的两倍。这表明对湮灭加热在合并残余物的演化中起着重要的作用。没有观测到驱动伽马射线爆发所必需的相对论性流出，因为旋转轴周围的特定加热速率不够高，这是由于来自大质量中子星的中微子驱动的抛射引起的重子负荷。讨论了相对论性流出的发射条件和喷出物中的核合成。
We performed general relativistic, long-term, axisymmetric neutrino radiation hydrodynamics simulations for the remnant formed after a binary neutron star merger, which consists of a massive neutron star and a torus surrounding it. As an initial condition, we employ the result derived in a three-dimensional, numerical relativity simulation for the binary neutron star merger. We investigate the properties of neutrino-driven ejecta. Due to the pair-annihilation heating, the dynamics of the neutrino-driven ejecta are significantly modified. The kinetic energy of the ejecta is about two times larger than that in the absence of pair-annihilation heating. This suggests that the pair-annihilation heating plays an important role in the evolution of merger remnants. The relativistic outflow, which is required for driving gamma-ray bursts, is not observed because the specific heating rate around the rotational axis is not sufficiently high, due to the baryon loading caused by the neutrino-driven ejecta from the massive neutron star. We discuss the condition for launching the relativistic outflow and the nucleosynthesis in the ejecta.