来自具有暂现和持续喷流的X射线双星的银河正负电子对湮灭辐射
Galactic Electron-Positron Annihilation Emission from X-Ray Binaries with Transient and Persistent Jets
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中文总结 AI 辅助
本研究指出X射线双星无法单独贡献银河正负电子对湮灭通量，通过格林函数求解粒子输运方程得到相关辐射的形态与热点，为观测研究X射线双星对银河正电子的贡献提供了依据。
中文摘要 AI 辅助
银心存在持续的0.511 MeV辐射，是正负电子对湮灭的特征。多种天体物理源可能是正电子的来源，但它们对总湮灭率的贡献尚不明确。X射线双星历来是主要候选者，可能贡献了银河正电子的很大一部分。X射线双星可通过Blandford-Znajek机制、冕中的双光子对产生，以及强磁化致密天体的单光子对产生过程产生正电子，这些正电子随后可能通过喷流或星风被输送到星际介质中。本研究认为X射线双星无法单独贡献正负电子对湮灭通量，我们给出了来自银河恒星族的X射线双星和恒星耀斑产生的0.511 MeV线通量与全天图，以及X射线双星产生的正电子对应的伽马射线连续谱。为此，我们利用格林函数求解粒子输运方程，得到的总形态略呈不对称，偏向负经度和正纬度方向。我们在生成的全天图中发现了5个0.511 MeV通量热点，并仔细研究了单个源对这些热点的贡献，对这些热点的观测可揭示X射线双星对银河正电子的贡献。即将到来的康普顿光谱仪和成像仪（COSI）任务有望成像天鹅座X-1附近的一个热点，而其他热点的探测则需要具备更高角分辨率（弧分级）的望远镜。
英文摘要
The Galactic Center exhibits a persistent 0.511 MeV emission characteristic of electron-positron annihilation. Various astrophysical sources may be responsible for supplying the positrons, yet their contributions with respect to the total annihilation rate is uncertain. X-ray binaries have historically been a primary candidate, possibly contributing a significant fraction of the Galactic positrons. X-ray binaries can produce positrons through the Blandford-Znajek mechanism, two-photon pair production in the corona, and/or one-photon pair production for strongly-magnetized compact objects. These positrons may then be channeled into the Interstellar Medium through jets or winds. In this work, we argue that X-ray binaries cannot contribute to the electron-positron annihilation flux alone. We present 0.511 MeV line fluxes and all-sky maps produced by X-ray binaries and stellar flares from the Galactic stellar population, along with the gamma-ray continuum from positrons produced by X-ray binaries. To do so, we solve the particle transfer equation using Green's functions. The total morphology is slightly asymmetric towards negative longitudes and positive latitudes. We find five 0.511 MeV flux hotspots in the generated all sky maps and scrutinize the contribution of individual sources to these hotspots. Observations of these hotspots can reveal the contribution of X-ray binaries to the Galactic positrons. The upcoming Compton Spectrometer and Imager (COSI) mission could image a hotspot near Cygnus X-1. The detection of the other hotspots requires a telescope with improved arcminute angular resolution.
