来自附近快速无线电爆发的脉冲星般的偏振角度
Ryan Mckinven1,2, Mohit Bhardwaj3, Tarraneh Eftekhari4,5
1Department of Physics, McGill University, Montréal, Quebec, Canada. ryan.mckinven@mcgill.ca.
Nature
|January 1, 2025
概括
快速无线电爆发 (FRB) 呈现出独特的极化角度旋转,支持磁层起源. 这一发现有助于排除这些神秘的宇宙信号的某些中子星祖先.
科学领域:
- 天文学与天体物理学
- 太空无线电短暂
背景情况:
- 快速无线电爆发 (FRB) 是来自银河系外距离的毫秒时间的无线电短暂.
- 它们的发射机制和起源在很大程度上是未知的,尽管与脉冲星的相似性表明中子星的起源.
- 与脉冲星不同,FRB通常显示最小的极化角度 (PA) 变化,当存在时,偏离标准旋转向量模型 (RVM).
研究的目的:
- 为了研究特定的快速无线电爆发的极化特性,FRB 20221022A.
- 确定FRB极化演变是否与已知的天体,如脉冲星或磁星相似.
- 根据观察到的极化行为来限制FRB的发射模型和原始类型.
主要方法:
- 使用加拿大强度测绘实验快速无线电爆发 (CHIME/FRB) 项目检测和定位FRB 20221022A.
- 分析爆发期间的线性极化位置角度 (PA).
- 使用旋转向量模型 (RVM) 建模观察到的 PA 演变.
主要成果:
- 在约2.5毫秒的时间里,FRB 20221022A表现出显著的~130° PA旋转.
- 这种PA演变与脉冲星和一些无线电磁星中观察到的特征S形曲线非常相似.
- 观察到的PA行为被RVM描述得很好,支持磁层发射模型.
结论:
- FRB 20221022A 的 PA 演变强烈支持磁层发射起源,排除涉及远距离冲击的模型.
- 这些发现与重复FRB的速度极度测量研究一致,加强了磁层模型.
- 虽然RVM符合数据,但具体参数 (倾斜,磁倾斜) 仍未确定,不包括非常短周期脉冲星作为原始物.
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