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arXiv 2104.12698astro-ph.HEphysics.plasm-ph
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磁星的生命周期:一种估算其年龄的新方法

The life cycle of magnetars: a novel approach to estimate their ages

Tushar Mondal

摘要:

异常X射线源和软伽马重复源是缓慢旋转、年轻和孤立的中子星,表现出零星的爆发和高X射线静态光度。据信,它们是由与“磁星”有关的超强磁场$B\sim10^{14}-10^{15}$ G提供动力的。在SGR 0418+5729的特殊情况下,定时参数意味着$6.1\times10^{12}$ G的偶极$B$ -场。这一发现挑战了传统的磁星$B$ -磁场强度、演化阶段和年龄的概念。在这里,我们提供了一种新的方法来估计磁星的年龄,考虑自洽的时间演化的等离子体填充的斜脉冲星与国家的最先进的磁层粒子加速间隙。磁星的旋转周期随着时间的推移而增加,这是由于引力波辐射、磁偶极子辐射和粒子风提取角动量。这些扭矩也改变了磁轴和旋转轴之间的夹角。对于SGR 0418+5729,我们获得了$1.0\times10^{14}$ G的偶极$B$ -场和$\sim18$ kyr的实际年龄,与磁星范例一致。

英文摘要:

Anomalous X-ray pulsars and soft gamma repeaters are slowly rotating, young, and isolated neutron stars exhibiting sporadic outbursts and high X-ray quiescent luminosities. They are believed to be powered by ultrastrong magnetic fields, $B\sim10^{14}-10^{15}$ G, associated with `magnetars'. In the peculiar case of SGR 0418+5729, timing parameters imply a dipolar $B$-field of $6.1\times10^{12}$ G. This discovery has challenged the traditional picture of magnetars in terms of $B$-field strengths, evolutionary stages, and ages. Here we provide a novel approach to estimate a magnetar's age by considering the self-consistent time evolution of a plasma-filled oblique pulsar with the state-of-the-art magnetospheric particle acceleration gaps. The rotational period of magnetars increases over time due to angular momentum extraction by gravitational-wave radiations, magnetic dipole radiations, and particle winds. These torques also change the obliquity angle between the magnetic and rotation axes. For SGR 0418+5729, we obtain a dipolar $B$-field of $1.0\times10^{14}$ G, and a realistic age of $\sim18$ kyr, consistent within the magnetar paradigm.

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。

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