标题： 黑洞-中子星双星中的中微子传输：中微子发射和动态质量抛射 显示英文标题

标题： Neutrino transport in black hole-neutron star binaries: neutrino emission and dynamical mass ejection

摘要： 我们通过完全广义相对论中微子辐射流体力学模拟研究了黑洞-中子星双星的合并过程，特别是在整个合并过程中中微子照射在动态质量抛射中的作用。 中微子传输是通过基于截断矩形式的近似传输方案来实现的。 尽管我们将黑洞与中子星的质量比固定为4，并将黑洞的无量纲自旋参数固定为0.75，但有限温度中子星物质的状态方程是变化的。 中子星潮汐破坏后形成的热吸积盘通过热对产生和随后电子/正电子在自由核子上的捕获，发出大量中微子，其峰值总光度约为1-3×10^53 erg s^(-1)。 然而，中微子照射并未显著改变动态抛射物的电子分数，该电子分数仍保持在初始中子星零温度下的无中微子β平衡值。 在本研究中考虑的模型进行的模拟持续到合并开始后的几毫秒内，由剩余盘中微子驱动的风组分质量相对于非常富含中子的动态组分来说可以忽略不计。 这些事实表明，黑洞-中子星双星的抛射物非常富含中子，预计能够容纳强烈的r过程核合成，除非磁场或粘滞过程对从盘中质量抛射有显著贡献。 我们还发现，随着盘质量的增加，峰值中微子光度并不一定增加，因为紧凑中子星的潮汐破坏可能导致质量较小但温度较高的剩余盘。 显示英文摘要

摘要： We study the merger of black hole-neutron star binaries by fully general-relativistic neutrino-radiation-hydrodynamics simulations throughout the coalescence, particularly focusing on the role of neutrino irradiation in dynamical mass ejection. Neutrino transport is incorporated by an approximate transfer scheme based on the truncated moment formalism. While we fix the mass ratio of the black hole to the neutron star to be 4 and the dimensionless spin parameter of the black hole to be 0.75, the equations of state for finite-temperature neutron-star matter are varied. The hot accretion disk formed after tidal disruption of the neutron star emits a copious amount of neutrinos with the peak total luminosity ~1--3x10^53 erg s^(-1) via thermal pair production and subsequent electron/positron captures on free nucleons. Nevertheless, the neutrino irradiation does not modify significantly the electron fraction of the dynamical ejecta from the neutrinoless beta-equilibrium value at zero temperature of initial neutron stars. The mass of the wind component driven by neutrinos from the remnant disk is negligible compared to the very neutron-rich dynamical component, throughout our simulations performed until a few tens milliseconds after the onset of merger, for the models considered in this study. These facts suggest that the ejecta from black hole-neutron star binaries are very neutron rich and are expected to accommodate strong r-process nucleosynthesis, unless magnetic or viscous processes contribute substantially to the mass ejection from the disk. We also find that the peak neutrino luminosity does not necessarily increase as the disk mass increases, because tidal disruption of a compact neutron star can result in a remnant disk with a small mass but high temperature.