We perform 3D general-relativistic magnetohydrodynamic simulations to model the jet break-out from the ejecta expected to be produced in a binary neutron-star merger. The structure of the relativistic outflow from the 3D simulation confirms our previous results from 2D simulations, namely, that a relativistic magnetized outflow breaking out from the merger ejecta exhibits a hollow core of θcore ≈ 4°, an opening angle of θjet ≳ 10°, and is accompanied by a wind of ejected matter that will contribute to the kilonova emission. We also compute the non-thermal afterglow emission of the relativistic outflow and fit it to the panchromatic afterglow from GRB170817A, together with the superluminal motion reported from VLBI observations. In this way, we deduce an observer angle of $\theta _{\rm obs}= 35.7^{\circ \, \, +1.8}_{\phantom{\circ \, \, }-2.2}$. We further compute the afterglow emission from the ejected matter and constrain the parameter space for a scenario in which the matter responsible for the thermal kilonova emission will also lead to a non-thermal emission yet to be observed.

中文翻译：

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中子星双星合并喷射物的 3D 磁化喷射爆发：喷射和喷射物的余辉发射

我们执行 3D 广义相对论磁流体动力学模拟，以模拟预期在双中子星合并中产生的喷射物的喷射爆发。来自 3D 模拟的相对论流出的结构证实了我们之前从 2D 模拟得到的结果，即从合并喷射物爆发的相对论磁化流出呈现出 θcore ≈ 4° 的空心核心， θjet ≳ 10° 的张角，并伴随着一股喷射物质的风，这将有助于千新星的发射。我们还计算了相对论流出的非热余辉发射，并将其与 GRB170817A 的全色余辉以及 VLBI 观测报告的超光速运动相匹配。这样，我们推导出观察者角度$\theta_{\rm obs}= 35.7^{\circ \, \, +1.8}_{\phantom{\circ \, \, }-2.2}$。