伽马射线脉冲星的多波段研究

We will carry out a theoretical investigation of gamma-ray emission process in pulsar magnetosphere. The Fermi gamma-ray telescope has detected more than 150 gamma-ray pulsars, but something new appears. Standard model predicts that the pulsars produce the GeV photons through the curvature radiation, and its spectrum decreases exponentially above 1-5GeV. Fermi has discovered unusual gamma-ray emitting pulsars, whose spectra conflict with the standard picture. “High-Energy Pulsars” emit the photons above 10GeV and the spectrum decreases “non”-exponentially above 10GeV. On the other hand, “Soft Gamma-ray Pulsars” are invisible by Fermi, but bright in hard X-ray bands. The precise emission mechanisms of these unusual pulsars are unknown. A unified picture that connects among soft gamma-ray pulsars, typical GeV pulsars, as well as high-energy pulsars could advance in understanding the high-energy emission process of the pulsars..We will argue that >10GeV emission from the high-energy pulsar is a result of non-stationary process, while the standard model discussed the stationary emission process. In our model, we will discuss the gamma-ray emission process within the framework of the outer gap model, which assumes the emission region located in outer magnetosphere. We argue that size of the outer gap oscillates with time, which results in the time dependent gamma-ray emission process. The high-energy emissions above 10GeV are produced when the outer gap thickness is very large. We speculate that although the spectrum of the individual pulsed emission has an exponential decay, the spectrum averaged over the time forms the non-exponential decay observed by Fermi..We will explore the possibility that the Earth viewing angle of the soft gamma-ray pulsars is a peculiar relative to the viewing angle for typical GeV gamma-ray pulsars. Our speculation is that because of this peculiar viewing geometry, we miss the GeV photons from the outer gap, but we can measure only hard X-ray/soft gamma-rays emitted through synchrotron radiation from the electron and positron pairs created outside the outer gap. We will simulate the dependency of X-ray/gamma-ray spectra and light curves on the viewing geometry, and we will discuss if this model could explain the multi-wavelength xobservations. .In the next decade, the Chinese next generation telescopes will enable us to start new science of the gamma-ray emitting pulsars. The Five Hundred Meter Aperture Spherical Telescope will find many new radio pulsars at the Fermi unidentified sources. A sky survey by The Hard X-ray Modulation Telescope will discover new soft gamma-ray pulsars. With these observations, we can address the questions that how gamma-ray luminosity depends on the spin down power, and how the population of the soft-gamma-ray pulsars depends on the age of the pulsars. We will carry out the theoretical study in multi-wavelength bands in order to compare with the future observations.

我们将对脉冲星磁层的伽马射线辐射机制进行理论研究。费米伽马射线望远镜发现了辐射伽玛射线的脉冲星的新类型，被称为“高能”脉冲星和“软γ射线脉冲星”。高能脉冲星发出的大于10GeV的伽玛射线被观测到了，而软伽玛射线脉冲星在GeV波段并不可见。标准模型并不能解释这种新型的伽马射线脉冲星，具体的辐射机制也是未知。我们将研究能统一解释软伽马射线脉冲星、典型GeV脉冲星和高能脉冲星的模型，这也将进一步理解脉冲星的高能辐射机制。在接下来的十年里，中国的五百米口径球面射电望远镜将在费米不确定的源中发现许多新的射电脉冲星。硬X射线调制望远镜的巡天将会发现新的软伽玛射线脉冲星。我们将进行的γ射线脉冲星族的理论研究，可与未来的观测相比较。

我们将对脉冲星磁层的伽马射线辐射机制进行理论研究。费米伽马射线望远镜发现了辐射 伽玛射线的脉冲星的新类型，被称为“高能”脉冲星和“软γ射线脉冲星”。高能脉冲星发出 的大于10GeV的伽玛射线被观测到了，而软伽玛射线脉冲星在GeV波段并不可见。标准模型并不 能解释这种新型的伽马射线脉冲星，具体的辐射机制也是未知。我们将研究能统一解释软伽马 射线脉冲星、典型GeV脉冲星和高能脉冲星的模型，这也将进一步理解脉冲星的高能辐射机制 。在接下来的十年里，中国的五百米口径球面射电望远镜将在费米不确定的源中发现许多新的 射电脉冲星。硬X射线调制望远镜的巡天将会发现新的软伽玛射线脉冲星。我们将进行的γ射 线脉冲星族的理论研究，可与未来的观测相比较。