Jet launching from binary neutron star mergers: Incorporating neutrino transport and magnetic fields
Jet launching from binary neutron star mergers: Incorporating neutrino transport and magnetic fields
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DOI：
10.1103/physrevd.105.104028
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发表时间：
2022-02
影响因子：
5
通讯作者：
Lunan Sun;M. Ruiz;S. Shapiro;A. Tsokaros
中科院分区：
文献类型：
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作者：
Lunan Sun;M. Ruiz;S. Shapiro;A. Tsokaros
我们进行广义相对论，磁流体动力学（GRMHD）模拟合并双中子星纳入中微子运输和磁场。我们新的中微子辐射输运模型采用了广义相对论截断矩（M1）形式主义。双星由两颗相同的无旋恒星组成，由SLy核状态方程（EOS）模拟。它们最初在准圆轨道上，并有一个从恒星内部延伸到外部的极向磁场，就像典型的恒星一样。我们插入合并后不久的中微子过程，并专注于中微子的作用，在发射后的超大质量中子星星（HMNS）残留物的旋转黑洞（BH）崩溃的喷气机。我们处理两个微观物理版本：一个（“热身”）演变一个单一的中微子物种，只考虑带电电流的过程，和其他演变的三个物种$（\nu_e，\bar{\nu}_e，\nu_{\rm x}）$和相关的过程。我们跟踪的演变，直到系统达到一个准平衡状态后BH形成。我们发现，BH +磁盘残留最终推出一个初期射流。电磁波印廷光度为$sim 10^{53} rm \，erg\，s^{-1}$，与典型的短伽玛射线暴（sGRB）一致。中微子冷却效应缩短了HMNS的寿命，并使引力波（GW）功率谱的主峰幅度有所降低。黑洞形成后，中微子帮助清理黑洞两极附近的物质，导致周围的碎片中重子含量较低。一旦达到准平衡，中微子的光度在$\sim 10^{52-53} \rm \，erg\，s^{-1}$范围内。与无中微子模型相比，我们观察到中微子的包含产生类似的喷出物质量，并在携带额外的角动量是低效的。
We perform general relativistic, magnetohydrodynamic (GRMHD) simulations of merging binary neutron stars incorporating neutrino transport and magnetic fields. Our new radiative transport module for neutrinos adopts a general relativistic, truncated-moment (M1) formalism. The binaries consist of two identical, irrotational stars modeled by the SLy nuclear equation of state (EOS). They are initially in quasicircular orbit and threaded with a poloidal magnetic field that extends from the stellar interior into the exterior, as in typical pulsars. We insert neutrino processes shortly after the merger and focus on the role of neutrinos in launching a jet following the collapse of the hypermassive neutron star (HMNS) remnant to a spinning black hole (BH). We treat two microphysical versions: one (a"warm-up") evolving a single neutrino species and considering only charged-current processes, and the other evolving three species $(\nu_e, \bar{\nu}_e, \nu_{\rm x})$ and related processes. We trace the evolution until the system reaches a quasiequilibrium state after BH formation. We find that the BH + disk remnant eventually launches an incipient jet. The electromagnetic Poynting luminosity is $\sim 10^{53} \rm \, erg\, s^{-1}$, consistent with that of typical short gamma-ray bursts (sGRBs). The effect of neutrino cooling shortens the lifetime of the HMNS, and lowers the amplitude of the major peak of the gravitational wave (GW) power spectrum somewhat. After BH formation, neutrinos help clear out the matter near the BH poles, resulting in lower baryon-loaded surrounding debris. The neutrino luminosity resides in the range $\sim 10^{52-53} \rm \,erg\,s^{-1}$ once quasiequilibrium is achieved. Comparing with the neutrino-free models, we observe that the inclusion of neutrinos yields similar ejecta masses and is inefficient in carrying off additional angular momentum.