爱因斯坦探针揭示银河系微类星体V4641 Sgr超高能发射的候选X射线对应体
Candidate X-ray Counterparts of Ultra-High-Energy Emission of the Galactic Microquasar V4641 Sgr Revealed by Einstein Probe
- Nanjing University（南京大学）
- Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Ministry of Education（南京大学现代天文与天体物理教育部重点实验室）
- Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）
- State Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所粒子天体物理国家重点实验室）
- Tianfu Cosmic Ray Research Center（天府宇宙线研究中心）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
利用爱因斯坦探针FXT发现微类星体V4641 Sgr周围与TeV发射重合的弥漫X射线结构，支持轻子起源，但UHE发射机制仍待确定。
AI中文摘要：
微类星体已成为有前景的PeV加速器候选体，能够将粒子加速至PeV能量，最近的观测揭示了与这些系统相关的延展结构中的超高能（UHE）γ射线发射。对这些延展结构的多波段研究对于理解UHE宇宙线（CRs）的加速、输运和辐射过程至关重要，然而观测证据仍然有限。在此，我们报告了使用爱因斯坦探针上的后随X射线望远镜（FXT）发现与微类星体V4641 Sgr南北两侧TeV γ射线发射区域空间重合的弥漫X射线结构。我们识别出位于距V4641 Sgr约20-40 pc的X射线结构，延伸超过数角分。这些结构在0.5-8 keV能带内每个单独节点表现出约1-3×10^-13 erg s^-1 cm^-2的X射线通量和Γ~2-3的光子指数。在单区轻子解释下，微弱的X射线发射意味着约1-2 μG的磁场。如果仅部分TeV-PeV发射由逆康普顿散射产生，其余发射来自强子相互作用，则更强的磁场仍有可能。EP-FXT观测支持在数十秒差距尺度上存在相对论性电子，而UHE γ射线发射的起源仍待确定。
英文摘要：
Microquasars have emerged as promising PeVatron candidates capable of accelerating particles to PeV energies, with recent observations revealing ultra-high-energy (UHE) $γ$-ray emission from extended structures associated with these systems. Multi-wavelength studies of such extended structures are crucial for understanding the acceleration, transport, and radiation processes of UHE cosmic rays (CRs), yet observational evidence remains limited. Here, we report the discovery of diffuse X-ray structures spatially coincident with the TeV $γ$-ray emission regions to the north and south of the microquasar V4641 Sgr, using the Follow-up X-ray Telescope (FXT) onboard the Einstein Probe. We identify X-ray structures located $\sim20$-$40$ pc from V4641 Sgr, extending over several arcminutes. These structures exhibit X-ray fluxes of $\sim1$-$3\times10^{-13}$ erg s$^{-1}$ cm$^{-2}$ and photon indices of $Γ\sim2$-3 in 0.5-8 keV per individual knot. Under the one-zone leptonic interpretation, the weak X-ray emission implies a magnetic field of order $1-2 μ$G. Stronger fields remain possible if only part of the TeV-PeV emission is produced by inverse Compton scattering, with the remaining emission arising from hadronic interactions. The EP-FXT observations support the presence of relativistic electrons on tens-of-parsec scales, while the origin of the UHE $γ$-ray emission remains open.
