磁星耀发外流中由引力波记忆驱动的电磁响应
Electromagnetic responses driven by gravitational-wave memory in magnetar-flare outflows
中文总结 AI 辅助
该研究针对磁星巨耀发产生的引力波记忆，通过数值模拟分析其驱动的电磁响应特性，明确了不同能量释放时标下的响应频率范围与能量分布，证实该电磁响应可在星际介质中传播。
中文摘要 AI 辅助
磁星巨耀发产生的不对称相对论性外流会形成阶跃式引力波（GW）记忆。在恒星周围的磁化正负电子对等离子体中，这种引力波记忆会驱动对应频率的横向电磁（EM）X模/快磁声波响应。我们利用该引力波记忆谱驱动冷正负电子对等离子体的全局波动方程，采用排除入射波的辐射边界条件，驱动产生的响应形成可到达源区外边界的出射电磁模。对于中心引擎能量释放时标为10、1和0.15μs的情况，90%的积分响应能量分别低于23.3 kHz、233 kHz和1.51 MHz；主要响应分布在10 kHz至1 MHz频段，当存在亚微秒级非对称能量分量时，还会显著延伸至1至3 MHz频段。该电磁响应可从源区逃逸，有望在星际介质中传播。
英文摘要
An asymmetric relativistic outflow from a magnetar giant flare produces a step-like gravitational-wave (GW) memory. In the magnetized pair plasma surrounding the star, such GW memory drives transverse electromagnetic (EM) X-mode/fast-magnetosonic responses at the corresponding frequencies. We use this GW-memory spectrum to drive a global wave equation for a cold electron--positron pair plasma. With radiative boundary conditions excluding incoming waves, the driven response forms an outgoing EM mode that reaches the outer boundary of the source region. For central-engine energy-release timescales of $10$, $1$, and $0.15\,μ\mathrm{s}$, 90\% of the integrated response energy lies below 23.3 kHz, 233 kHz, and 1.51 MHz, respectively. The principal response occupies the 10 kHz--1 MHz frequency band; a substantial extension into the 1--3 MHz frequency band also appears when a submicrosecond asymmetric-energy component is present. The electromagnetic response can escape from the source region and potentially propagate in the interstellar medium.
