The recent discovery of a fast radio burst (FRB 200428) from the Galactic magnetar SGR 1935+2154 robustly indicated that FRB phenomena can sometimes be produced by magnetars, although it is uncertain whether the cosmological FRBs can share the same origin with this Galactic event. The association of FRB 200428 with an X-ray burst (XRB) further offers important implications for the physical processes responsible for the FRB phenomena. By assuming that the XRB emission is produced in the magnetosphere of the magnetar, we investigate the possibility of that the FRB emission is produced by the synchrotron maser (SM) mechanism, which is powered by a shock due to the collision of an $e^{\pm}$ ejecta with a baryonic cloud. It is found that this shock-powered SM model can in principle account for the FRB 200428 observations, if the collision just occurred on the line of sight and the ejecta lunched by magnetar bursts can have appropriate ingredients and structures. To be specific, a burst ejecta should consist of an ultra-relativistic and extremely highly collimated $e^{\pm}$ component and a sub-relativistic and wide-spreading baryonic component. The cloud blocking the $e^{\pm}$ ejecta is just a remnant of a previous baryonic ejecta. Meanwhile, as a result of the synchrotron emission of the shocked material, an intense millisecond X-ray pulse is predicted to overlap the magnetosphere XRB emission, which in principle provides a way to test the model. Additionally, the peak frequency of the SM radiation is constrained to be about a few hundred MHz and the radiation efficiency is around $10^{-4}$.

中文翻译：

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激波驱动的同步加速器微波激射模型与银河 FRB 200428 的对抗

最近从银河磁星 SGR 1935+2154 发现的快速射电暴 (FRB 200428) 有力地表明，FRB 现象有时可以由磁星产生，尽管尚不确定宇宙学 FRB 是否可以与这次银河事件共享同一起源。FRB 200428 与 X 射线爆发 (XRB) 的关联进一步为导致 FRB 现象的物理过程提供了重要意义。通过假设 XRB 发射是在磁星的磁层中产生的，我们研究了 FRB 发射是由同步加速器脉泽（SM）机制产生的可能性，该机制由 $e^ 碰撞引起的激波提供动力。 {\pm}$ 带有重子云的喷射物。发现这个激波驱动的 SM 模型原则上可以解释 FRB 200428 的观测结果，如果碰撞刚好发生在视线上，磁星爆发产生的喷出物可以有适当的成分和结构。具体来说，爆发喷射物应该由一个超相对论和高度准直的 $e^{\pm}$ 分量和一个亚相对论和广泛传播的重子分量组成。阻挡 $e^{\pm}$ 喷射物的云只是先前重子喷射物的残余物。同时，由于受到冲击材料的同步加速器发射，预计会有一个强烈的毫秒级 X 射线脉冲与磁层 XRB 发射重叠，这在原理上提供了一种测试模型的方法。此外，SM辐射的峰值频率被限制在几百MHz左右，辐射效率约为$10^{-4}$。