低光度活动星系核的辐射低效吸积流驱动的风产生的TeV伽马射线和中微子
TeV Gamma Rays and Neutrinos from Winds Driven by Radiatively Inefficient Accretion Flows of Low-Luminosity Active Galactic Nuclei
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中文总结 AI 辅助
本研究针对LHAASO探测到的LLAGN NGC 4278宁静期TeV伽马射线，提出RIAF驱动风的新机制，建模重现其辐射，还可推广至Sgr A*，为LLAGN辐射机制提供新解释。
中文摘要 AI 辅助
高海拔宇宙线观测站（LHAASO）近期首次从缺乏强喷流的低光度活动星系核（LLAGN）探测到TeV伽马射线，该源NGC 4278是距离较近的LLAGN之一，可作为模板详细研究以探索更遥远的天体。以往多数研究聚焦于月尺度变化的伽马射线活动，试图用弱喷流解释，而本文转而关注NGC 4278宁静期的辐射，提出基于辐射低效吸积流（RIAF）驱动的风的不同机制，具体对风驱动激波处的粒子加速进行建模并计算多信使辐射。为匹配LHAASO在宁静期报告的TeV伽马射线流量，模型要求风功率≤2×10^43 erg s^-1，注入宇宙线的谱指数为2.0；研究表明，对于浅吸积轮廓，这可通过100pc尺度观测到的电离气体的邦迪吸积实现。本文还讨论了利用多信使观测检验风驱动激波情景的可行性，作为另一重要应用，将模型扩展至最近的LLAGN Sgr A*，并证明用合理参数可重现其TeV伽马射线辐射。研究结果提示，RIAF驱动的风可能是LLAGN中的普遍辐射机制，使该类天体成为伽马射线发射体和宇宙线加速器的潜在重要群体。
英文摘要
Recently, the Large High Altitude Air Shower Observatory (LHAASO) reported the first TeV gamma-ray detection from a low-luminosity active galactic nucleus (LLAGN) lacking a strong jet. This source, NGC 4278, is one of the nearest LLAGNs that can be studied in detail as a template for more distant objects. Most previous studies have focused on the month-scale-variable gamma-ray activities, seeking to explain them with weak jets. We focus instead on NGC 4278's quiet-period emission, proposing a different mechanism based on a wind launched from a radiatively inefficient accretion flow (RIAF). In particular, we model particle acceleration at a wind-driven shock and calculate the resulting multimessenger emission. To match the TeV gamma-ray fluxes reported by LHAASO in the quiet period, our model requires a wind power of $\lesssim2\times10^{43}~\mathrm{erg~s^{-1}}$ with a spectral index of injected cosmic rays of 2.0. We show that this is achievable through Bondi accretion of the ionized gas observed on the 100-pc scale, for a shallow accretion profile. We discuss the testability of our wind-driven shock scenario with multimessenger observations. As another important application, we extend our model to Sgr A*, the nearest LLAGN, and show that its TeV gamma-ray emission is reproduced with reasonable parameters. Our results suggest that RIAF-driven winds may be a generic emission mechanism in LLAGNs, making this class a potentially important population of both gamma-ray emitters and cosmic-ray accelerators.
发表机构
- The University of Osaka（大阪大学）
- The Ohio State University（俄亥俄州立大学）
- The Pennsylvania State University（宾夕法尼亚州立大学）
- Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。
