发表机构
International Center for Theoretical Sciences, Tata Institute of Fundamental Research; Center for Theoretical Physics, Polish Academy of Sciences; Department of Theoretical Physics and Astrophysics, Masaryk University; McGill University; Trottier Space Institute（塔塔基础研究所国际理论科学中心; 波兰科学院理论物理中心; 马萨里克大学理论与天体物理学系; 麦吉尔大学; 特罗蒂尔太空研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过半解析跨磁声激波解分析，发现低角动量磁化吸积流的驻激波可为SgrA*的弱至中等X射线耀斑提供能量，最强耀斑则需额外磁能耗散通道实现。
AI 中文摘要
来自人马座A*（SgrA*）的X射线耀斑在持续时间、流量和光度上跨度很大，但其起源仍未明确。我们检验低角动量磁化吸积流中的驻激波是否能提供可行的能量储层来解释这些事件。利用半解析跨磁声激波解，我们估计激波后下游流中可获得的动能，并将其与25年的钱德拉（Chandra）X射线耀斑星表进行比较。对于每个理论解，我们计算所需效率ε=E_data/E_sh，其中E_data是每个耀斑的观测辐射能量，E_sh是激波流中的可用能量。值得注意的是，弱耀斑要求ε约为10⁻³至10⁻²，而中等耀斑要求为百分之几。我们对弱旋转和强旋转情况都进行了分析，得到的弱至中等耀斑能量预算保持不变。对于基准吸积率和热光度校正，驻激波中的动能储层足以满足观测到的弱至中等耀斑群体，而最强的事件可能需要更高的效率，这可通过额外的磁能耗散通道来实现。
英文摘要
X-ray flares from Sgr~A* span broad ranges in duration, fluence, and luminosity, but their origin remains unsettled. We test whether standing shocks in low-angular-momentum magnetized accretion flows can provide a viable energy reservoir to account for these events. Using semi-analytic trans-magnetosonic shock solutions, we estimate the kinetic energy available in the downstream post-shock flow and compare it with the 25-year \textit{Chandra} X-ray flare catalog. For each theoretical solution, we compute the required efficiency $ε=E_{\rm data}/E_{\rm sh}$, where $E_{\rm data}$ is the observed radiated energy for each flare and $E_{\rm sh}$ is the available energy in the shocked flow. Notably, the weak flares require $ε\sim10^{-3}$--$10^{-2}$, while moderate flares require a few percent. We perform the analyses for weakly and highly spinning cases, and the resulting weak-to-moderate flare energy budget remains unchanged. For the fiducial accretion rate and bolometric correction, the kinetic energy reservoir in standing shock is sufficient for the observed weak-to-moderate flare population, whereas the strongest events likely require higher efficiency which can be mediated via additional magnetic energy dissipation channel.
Comments12 pages, 4 figures. Accepted for publication in The Astrophysical Journal
