Inverse Compton emission from millisecond pulsars in the Galactic bulge
Inverse Compton emission from millisecond pulsars in the Galactic bulge
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DOI：
10.1103/physrevd.99.123020
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发表时间：
2019-01
影响因子：
5
通讯作者：
D. Song;O. Macias;S. Horiuchi
中科院分区：
文献类型：
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作者：
D. Song;O. Macias;S. Horiuchi
对费米伽马射线太空望远镜数据的分析揭示了一个朝向银河系中心的过量扩散伽马射线源，该中心延伸到大约20度的纬度。主流理论认为，这一GeV的过剩是大量微弱毫秒双星（MSP）的总辐射。这些粒子注入的电子和正电子（$e^\pm$）可以通过将周围的光子向上散射成伽马射线能量来产生可检测的逆康普顿（IC）发射。在这项工作中，我们使用GALPROP计算这样的IC排放。一个三轴的三维模型，从一个适合的红外数据得到的膨胀星被用来作为一个示踪剂的推定MSP人口。将该模型与MSP在空间上分布为Navarro-Frenk-白色平方分布的模型进行比较。我们表明，这两种模式的光谱是无法区分的，但它们的空间形态有显着的可识别的功能。以上$\sim$TeV能量的IC组件携带关于注入的$e^\pm$的空间形态的信息。这种差异可能被未来的高能伽马射线探测器，如切伦科夫望远镜阵列，用于提供一个可行的多波长处理的MSP起源的GeV过剩。
Analyses of Fermi Gamma-Ray Space Telescope data have revealed a source of excess diffuse gamma rays towards the Galactic center that extends up to roughly $\pm$20 degrees in latitude. The leading theory postulates that this GeV excess is the aggregate emission from a large number of faint millisecond pulsars (MSPs). The electrons and positrons ($e^\pm$) injected by this population could produce detectable inverse-Compton (IC) emissions by up-scattering ambient photons to gamma-ray energies. In this work, we calculate such IC emissions using GALPROP. A triaxial three-dimensional model of the bulge stars obtained from a fit to infrared data is used as a tracer of the putative MSP population. This model is compared against one in which the MSPs are spatially distributed as a Navarro-Frenk-White squared profile. We show that the resulting spectra for both models are indistinguishable, but that their spatial morphologies have salient recognizable features. The IC component above $\sim$TeV energies carries information on the spatial morphology of the injected $e^\pm$. Such differences could potentially be used by future high-energy gamma-ray detectors such as the Cherenkov Telescope Array to provide a viable multiwavelength handle for the MSP origin of the GeV excess.