标题： 显著的微类星体S26：超爱丁顿佩瓦特龙？ 显示英文标题

标题： The remarkable microquasar S26: a super-Eddington PeVatron?

摘要： 上下文。 S26是一个具有已发现最强大喷流的河外微类星体。 它们的动能光度为$L_{\rm j}\sim5\times 10^{40}\,{\rm erg\,s^{-1}}$。 这意味着黑洞的吸积功率应超过爱丁顿极限，约为$L_{\rm acc}\sim L_{\rm j}$。 然而，该系统的观测X射线通量表明其吸积光度明显低于爱丁顿极限，为$L_{\rm X}\approx 10^{37}\,{\rm erg\,s^{-1}}$。 目标。 我们的目标是表征S26的性质，解释系统辐射，并研究超爱丁顿微类星体作为潜在PeVatron源的可行性。 方法。 我们首先分析通过XMM-Newton获得的S26的X射线观测数据，并对超爱丁顿盘及其风进行建模。 然后，我们开发一个喷流模型，并研究在喷流基部附近和终端区域产生的激波中的粒子加速和辐射过程。 结果。 我们发现S26中喷流与明显盘光度之间的差异是由于超爱丁顿盘喷出的风完全吸收了盘辐射。 非热X射线是在喷流基部附近产生的，而热X射线则在终端区域发射。 使用澳大利亚望远镜紧凑阵列观测到的射电辐射可以解释为在叶状结构中的反向激波中产生的同步辐射。 我们还发现S26可以在内部喷流和叶状结构中将质子加速到PeV能量。 在叶状结构中加速的超高能质子以总功率为$\sim 10^{36}\,{\rm erg\,s^{-1}}$的方式注入到星际介质中。 结论。 我们得出结论，S26是一个具有密集盘驱动风的超爱丁顿微类星体，该风遮蔽了来自内盘的X射线辐射，而系统的超爱丁顿特性允许宇宙射线加速到PeV能量。 显示英文摘要

摘要： Context. S26 is an extragalactic microquasar with the most powerful jets ever discovered. They have a kinetic luminosity of $L_{\rm j}\sim5\times 10^{40}\,{\rm erg\,s^{-1}}$. This implies that the accretion power to the black hole should be super-Eddington, of the order of $L_{\rm acc}\sim L_{\rm j}$. However, the observed X-ray flux of this system indicates an apparent very sub-Eddington accretion luminosity of $L_{\rm X}\approx 10^{37}\,{\rm erg\,s^{-1}}$. Aims. We aim to characterize the nature of S26, explain the system emission, and study the feasibility of super-Eddington microquasars as potential PeVatron sources. Methods. We first analyze X-ray observations of S26 obtained with XMM-Newton and model the super-Eddington disk and its wind. We then develop a jet model and study the particle acceleration and radiative processes that occur in shocks generated near the base of the jet and in its terminal region. Results. We find that the discrepancy between the jet and the apparent disk luminosities in S26 is caused by the complete absorption of the disk radiation by the wind ejected from the super-Eddington disk. The nonthermal X-rays are produced near the base of the jet, and the thermal X-rays are emitted in the terminal regions. The radio emission observed with the Australia Telescope Compact Array can be explained as synchrotron radiation produced at the reverse shock in the lobes. We also find that S26 can accelerate protons to PeV energies in both the inner jet and the lobes. The ultra-high energy protons accelerated in the lobes are injected into the ISM with a total power of $\sim 10^{36}\,{\rm erg\,s^{-1}}$. Conclusions. We conclude that S26 is a super-Eddington microquasar with a dense disk-driven wind that obscures the X-ray emission from the inner disk, and that the supercritical nature of the system allows the acceleration of cosmic rays to PeV energies.