arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1702.08644astro-ph.HE
收藏

FRB 121102中的一颗闪耀磁星?

A flaring magnetar in FRB 121102?

Andrei M. Beloborodov

摘要:

FRB 121102的持久射电对应物估计有$N\sim 10^{52}$粒子,能量为$E_N\sim 10^{48}$ erg,大小为$R\sim 10^{17}$ cm。它可以是一个星云,由磁星(一颗中子星,由其磁能(而不是旋转能)提供能量)间歇性流出而膨胀和加热。该天体还很年轻,经常在中子星核心加速的双极扩散驱动下释放出磁耀斑能量,为星云提供能量,并产生明亮的毫秒级爆发。星云中的粒子数量与巨大耀斑的离子喷出物一致。星云中还可能含有中子星诞生数月后冻结出来的电子-正电子对$N_\pm\sim 10^{51}$;同样的机制也解释了蟹状星云中的$N_\pm$。FRB 121102周围的持续源可能是由磁星喷出物激发的磁耗散和内波加热的。由波产生的体积加热解释了星云在产生无线电辐射方面的巨大效率。重复的无线电爆发被认为发生在离磁星更近的地方,磁星闪耀的磁层将超相对论性的内部冲击驱动到磁星风中。的冲击介导的拉莫尔旋转,形成一个GHz的微波激射器所观察到的毫秒的持续时间。此外,耀斑喷出物会变得缺乏电荷,然后转化为电磁波。

英文摘要:

The persistent radio counterpart of FRB 121102 is estimated to have $N\sim 10^{52}$ particles, energy $E_N\sim 10^{48}$ erg, and size $R\sim 10^{17}$ cm. The source can be a nebula inflated and heated by an intermittent outflow from a magnetar --- a neutron star powered by its magnetic (rather than rotational) energy. The object is young and frequently liberating energy in magnetic flares driven by accelerated ambipolar diffusion in the neutron star core, feeding the nebula and producing bright millisecond bursts. The particle number in the nebula is consistent with ion ejecta from giant flares. The nebula may also contain the freeze-out of electron-positron pairs $N_\pm\sim 10^{51}$ created months after the neutron star birth; the same mechanism offers an explanation for $N_\pm$ in the Crab nebula. The persistent source around FRB 121102 is likely heated by magnetic dissipation and internal waves excited by the magnetar ejecta. The volumetric heating by waves explains the nebula's enormous efficiency in producing radio emission. The repeating radio bursts are suggested to occur much closer to the magnetar, whose flaring magnetosphere drives ultrarelativistic internal shocks into the magnetar wind. The shocks are mediated by Larmor rotation that forms a GHz maser with the observed ms duration. Furthermore, the flare ejecta can become charge-starved and then convert to electromagnetic waves.

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。

↑