利用费米卫星大面积望远镜对脉冲星的观测研究

Fermi Large Area Telescope Studies of Pulsars

费米γ射线空间望远镜(Fermi)自2008年8月观测任务开始以来,以其优越的观测性能开启了γ射线天文学研究的新纪元。其搭载的大面积望远镜(LAT)在脉冲星探测和研究方面取得了巨大的成功。除了探测到已知脉冲星的γ射线脉冲辐射信号外,LAT还能够利用γ射线数据的盲寻技术独立发现脉冲星,此外还提供了大量γ射线源进行射电脉冲搜寻。Fermi-LAT的观测带来了γ射线脉冲星数量的显著增长,确立了脉冲星是银河系内主要的γ射线源,并且探测到了毫秒脉冲星的γ射线辐射。一般来说,在长时标下脉冲星的γ射线辐射流量稳定且脉冲形状多呈现双峰结构,能谱可由具有指数截断的幂律谱描述。综述了利用Fermi-LAT数据寻找脉冲辐射信号的方法和研究γ射线脉冲星所得到的主要结果,并简要介绍了近年来在脉冲星研究方面取得的新成果。

The Fermi Gamma-ray Space Telescope, with its great capabilities, has revolutionized our view of high-energy γ-ray sky. The Large Area Telescope(LAT) onboard Fermi achieved magnificent results for discovering γ-ray pulsars in blind searches in LAT data alone. This, combined with the methods of γ-ray phase-folding with known rotation ephemeris and radio pulsation searches targeting un-associated LAT sources, have greatly increased the number of γ-ray pulsars. Thus far, 234 γ-ray pulsars have been detected,among which 103 are millisecond pulsars, having confirmed that pulsars are prominent γ-ray sources in our Galaxy. Based on the wealthy Fermi-LAT results, different theoretical models of the high-energy emission in the pulsar’s magnetospheres have been developed and improved to explain the observed properties. It has also been established that γ-ray pulsars generally have spin-down energy˙E on the order of 1026~1031 J · s-1. The emission from pulsars is generally stable in long-term observations and the pulsation profiles often show a double-peak structure. Their spectra have a form of an exponentially cutoff power law with cutoff energies at several Ge V. In this article, we review the results about pulsar discoveries and their main properties from the Fermi observations in the past 10 years, which include a brief introduction to different peculiar γ-ray pulsar systems found in recent years.