arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1309.4271astro-ph.HEnucl-th
收藏

在核心坍缩超新星模拟中来自核去激发的中子对发射

Neutrino-pair emission from nuclear de-excitation in core-collapse supernova simulations

Tobias Fischer, Karlheinz Langanke, Gabriel Martinez-Pinedo

摘要:

我们研究了中微子对生产的影响,从高激发重核的核心坍缩超新星模拟的去激发,核心反弹后的几个100毫秒的演变。我们的研究是基于AGILE-Boltztran超新星代码,其特点是广义相对论辐射流体力学和准确的三味玻尔兹曼中微子输运球对称。在我们的模拟中,用两种不同的方式描述了核去激发过程。首先,我们遵循富勒和迈耶[Astrophys. J.376,701(1991)],其基于在非相互作用核子的核费米气体模型的框架中导出的强度函数。其次,我们根据对选定的核基态的测量参数化了允许和禁止的强度分布。我们通过应用Brink假设和细致平衡来确定去激励强度。对于这两种方法,我们发现,核去激发对超新星动力学没有影响。然而,我们发现,在坍缩阶段,核去激发是产生电子反中微子以及重轻子味(反)中微子的主要来源。在足够高的密度下,相关的中微子光谱会受到与周围物质相互作用的影响,这使得正确的中微子输运模拟对于确定中微子能量损失率非常重要。我们发现,即使包括核去激发,在崩溃阶段的能量损失是压倒性的主要由电子捕获产生的电子中微子。

英文摘要:

We study the impact of neutrino-pair production from the de-excitation of highly excited heavy nuclei on core-collapse supernova simulations, following the evolution up to several 100 ms after core bounce. Our study is based on the AGILE-Boltztran supernova code, which features general relativistic radiation hydrodynamics and accurate three-flavor Boltzmann neutrino transport in spherical symmetry. In our simulations the nuclear de-excitation process is described in two different ways. At first we follow the approach proposed by Fuller and Meyer [Astrophys. J. 376,701 (1991)], which is based on strength functions derived in the framework of the nuclear Fermi-gas model of non-interacting nucleons. Secondly, we parametrize the allowed and forbidden strength distributions in accordance with measurements for selected nuclear ground states. We determine the de-excitation strength by applying the Brink hypothesis and detailed balance. For both approaches, we find that nuclear de-excitation has no effect on the supernova dynamics. However, we find that nuclear de-excitation is the leading source for the production of electron antineutrinos as well as heavy-lepton flavor (anti)neutrinos during the collapse phase. At sufficiently high densities, the associated neutrino spectra are influenced by interactions with the surrounding matter, making proper simulations of neutrino transport important for the determination of the neutrino-energy loss rate. We find that even including nuclear de-excitations, the energy loss during the collapse phase is overwhelmingly dominated by electron neutrinos produced by electron captures.

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。

↑