XMM-Newton解析PeVatron微类星体V4641 Sgr中的秒差距尺度X射线喷流
XMM-Newton Resolves Parsec-scale X-ray Jets in the PeVatron Microquasar V4641 Sgr
- Institute for Cosmic Ray Research, The University of Tokyo（宇宙线研究所，东京大学）
- Interdisciplinary Theoretical & Mathematical Science Center (iTHEMS), RIKEN（理化学研究所交叉理论与数学科学中心(iTHEMS)）
- INAF-Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）
- Como Lake Center for Astrophysics (CLAP), DiSAT, Università degli Studi dell’Insubria（因苏布里亚大学地球科学与技术系科莫湖天体物理中心）
- Columbia Astrophysics Laboratory, Columbia University（哥伦比亚大学哥伦比亚天体物理学实验室）
- The University of Miyazaki（宫崎大学）
- 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重点实验室）
- Tianfu Cosmic Ray Research Center（天府宇宙线研究中心）
- Department of Physics and Astronomy, University of Manitoba（曼尼托巴大学物理与天文学系）
- Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·潘内库克天体物理研究所）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
本研究利用XMM-Newton在微类星体V4641 Sgr中发现延展的秒差距尺度X射线喷流，与伽马射线发射空间重合，支持轻子起源，为PeVatron微类星体提供关键观测特征。
中文摘要 AI 辅助
微类星体V4641 Sagittarii（V4641 Sgr）最近通过探测到0.8 PeV的度尺度伽马射线辐射，被确立为银河系中最强大的PeV宇宙射线加速器（PeVatron）之一。利用XMM-Newton，我们在其宁静期对其伽马射线发射区域进行了X射线巡天。我们发现了V4641 Sgr南北方向的延展X射线发射，与射电喷流轴对齐，首次揭示了延伸超过数十秒差距的X射线喷流结构。北侧和南侧的结节状特征，分别命名为n1和s1，位于距中央双星约20秒差距处，并与伽马射线发射在空间上重合。每个结的X射线发射，其特征为光子指数$\Gamma_X = 1.9 \pm 0.1_{\rm stat} \pm 0.5_{\rm syst}$，在2--10 keV能带的能量通量约为$(2--4)\times10^{-13}$~erg~cm$^{-2}$~s$^{-1}$，可能具有非热起源，表明来自加速电子的同步辐射。X射线与伽马射线发射之间的形态重合支持伽马射线的轻子场景，尽管X射线发射比伽马射线发射区域更紧凑，且强子场景不能被排除。通过X射线到伽马射线的建模，我们获得了3--5~$\mu$G的弱磁场强度。我们提出新探测到的X射线结节代表粒子加速位点，例如由V4641 Sgr驱动的喷流终止或（重新）准直区域，或类似于SS~433/W50中外喷流结节的下游结构。这一发现表明，沿喷流的延展X射线发射将是PeVatron微类星体中的一个关键特征，但此前被忽视。
英文摘要
The microquasar V4641 Sagittarii (V4641 Sgr) has recently been established as one of the most powerful Galactic PeV cosmic-ray accelerators (PeVatrons) through the detection of degree-scale gamma-ray emission to 0.8 PeV. Using XMM-Newton, we performed an X-ray survey of its gamma-ray-emitting regions during the quiescent phase. We discovered extended X-ray emission to the north and south of V4641 Sgr, aligned with the radio-jet axis, revealing X-ray jet structures extending over several tens of parsecs for the first time. The northern and southern knot-like features, dubbed n1 and s1, are located approximately 20 pc from the central binary and spatially coincident with the gamma-ray emission. The X-ray emission from each knot, characterized by a photon index of $Γ_X = 1.9 \pm 0.1_{\rm stat} \pm 0.5_{\rm syst}$ and an energy flux of $\sim$(2--4)$\times10^{-13}$~erg~cm$^{-2}$~s$^{-1}$ in the 2--10 keV band, is likely non-thermal in origin, indicating synchrotron radiation from accelerated electrons. The morphological coincidence between the X-ray and gamma-ray emission favors a leptonic scenario for the gamma rays, although the X-ray emission is more compact than the gamma-ray-emitting region and the hadronic scenario cannot be excluded. Through X-ray to gamma-ray modeling, we obtain a weak magnetic field strength of 3--5~$μ$G. We propose that the newly detected X-ray knots represent particle-acceleration sites, such as jet termination or (re-)collimation regions powered by V4641 Sgr, or downstream structures analogous to the knots of the outer jets in SS~433/W50. This discovery suggests that extended X-ray emission along jets would be a key signature, yet previously overlooked, in PeVatron microquasars.
