论文标题
在中子合并的磁化喷气机的开头：GRB170817A的情况
On the opening angle of magnetised jets from neutron-star mergers: the case of GRB170817A
论文作者
论文摘要
GW170817/GRB170817A的观察结果证实，中子二进制二进制的合并是短伽马射线爆发的祖先。在简短的伽马射线爆发的标准图片中，合并后推出了准直的相对论流出，并成功地从周围的弹出物质中爆发出来。利用来自数值二进制中子星级合并仿真启发的初始条件，我们进行了一般性的流体动力学（HD）和磁性水力学（MHD）模拟，在其中启动了射流并自言自语。完整的模拟集表明：（i）MHD喷气机具有内在的能量和速度极性结构，并带有``hollow core''''''角度$θ_ {\ rm core} \ core} \ lock} \ loct of4^{\ circ} {\ circ} -5^{\ circ} $ unter os $ unge和$ unigh jet} \ gtrsim10^{\ circ} $; （ii）MHD喷气机弹出大量的物质和两个数量级，高于HD喷头； （iii）MHD喷气机中的能量分层自然产生幂律能量缩放$ E（>γβ）\ Propto（γβ）^{ - 4.5} $; （iv）MHD喷气机提供适合GRB170817A的余辉数据，它们比HD喷气机的数据相对好，没有免费参数； （v）最后，两个最佳拟合HD/MHD模型都建议GRB170817A的观察角$θ_ {\ rm obs} \ simeq 21^{\ circ} $。
The observations of GW170817/GRB170817A have confirmed that the coalescence of a neutron-star binary is the progenitor of a short gamma-ray burst. In the standard picture of a short gamma-ray burst, a collimated highly relativistic outflow is launched after merger and it successfully breaks out from the surrounding ejected matter. Using initial conditions inspired from numerical-relativity binary neutron-star merger simulations, we have performed general-relativistic hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations in which the jet is launched and propagates self-consistently. The complete set of simulations suggests that: (i) MHD jets have an intrinsic energy and velocity polar structure with a ``hollow core'' subtending an angle $θ_{\rm core}\approx4^{\circ}-5^{\circ}$ and an opening angle of $θ_{\rm jet}\gtrsim10^{\circ}$; (ii) MHD jets eject significant amounts of matter and two orders of magnitude more than HD jets; (iii) the energy stratification in MHD jets naturally yields the power-law energy scaling $E(>Γβ)\propto(Γβ)^{-4.5}$; (iv) MHD jets provide fits to the afterglow data from GRB170817A that are comparatively better than those of the HD jets and without free parameters; (v) finally, both of the best-fit HD/MHD models suggest an observation angle $θ_{\rm obs} \simeq 21^{\circ}$ for GRB170817A.
