On the Time-Frequency Downward Drifting of Repeating Fast Radio Bursts
On the Time-Frequency Downward Drifting of Repeating Fast Radio Bursts
复制标题
关于重复快速射电暴的时间频率向下漂移
DOI：
10.3847/2041-8213/ab1aab
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发表时间：
2019
影响因子：
7.9
通讯作者：
Xu Renxin
中科院分区：
文献类型：
--
作者：
Wang Weiyang;Zhang Bing;Chen Xuelei;Xu Renxin
据报道，新发现的第二个重复快速无线电突发（FRB）源FRB 180814.J0422+73表现出时频向下漂移的模式，这在第一个重复FRB 121102中也可以看到。我们提出了一个通用的几何模型来解释观测到的子脉冲频率的向下漂移，在相干曲率辐射的框架内，由电子-正电子对束在磁层的中子星星（NS）。一个突然的触发事件激发了这些相干的带电粒子束，它们沿着沿着开放的场线向外流动。当磁力线扫过视线时，后来看到的聚束会更远地进入磁力线的弯曲程度较低的部分，从而以较低的频率发射。我们用这个模型来解释两个FRB生成场景中的时频向下漂移，从缓慢旋转的NS的内部间隙区域的瞬态脉冲星般的火花，以及外部触发的磁层重新配置被称为“宇宙梳”。
The newly discovered second repeating fast radio burst (FRB) source, FRB 180814.J0422+73, was reported to exhibit a time-frequency downward drifting pattern, which is also seen in the first repeater FRB 121102. We propose a generic geometrical model to account for the observed downward drifting of sub-pulse frequency, within the framework of coherent curvature radiation by bunches of electron-positron pairs in the magnetosphere of a neutron star (NS). A sudden trigger event excites these coherent bunches of charged particles, which stream outward along open field lines. As the field lines sweep across the line of sight, the bunches seen later travel farther into the less-curved part of the magnetic field lines, thus emitting at lower frequencies. We use this model to explain the time-frequency downward drifting in two FRB generation scenarios, the transient pulsar-like sparking from the inner gap region of a slowly rotating NS, and the externally triggered magnetosphere reconfiguration known as the “cosmic comb.”