未证认的PeV源LHAASO J2108+5157：微类星体遗迹？
The unidentified PeV source LHAASO J2108+5157: A microquasar remnant?
- Universidad de Jaén（哈恩大学）
- Instituto Argentino de Radioastronomía (CCT La Plata, CONICET（阿根廷射电天文研究所）
- CICPBA（拉普拉塔国立大学天文与地球科学学院）
- UNLP)（巴塞罗那大学）
- Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata
- Universitat de Barcelona
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究提出含时强子模型，将LHAASO J2108+5157的双峰伽马射线谱解释为单一质子群的输运效应，支持其为化石微类星体遗迹，并强调遗迹喷流系统是银河系PeV加速器的可行类别。
AI中文摘要：
背景。LHAASO J2108+5157是银河系内最引人注目的超高能伽马射线源之一。它被探测到高达数百TeV的能量，但在较低频段缺乏明确的对应体。费米-拉特（Fermi-LAT）观测揭示了一个与PeV发射空间重合的致密GeV源，而VERITAS和LST-1在中间TeV波段施加了严格的上限，在GeV和TeV能域之间产生了显著的谱抑制。目标。我们研究一个含时强子模型，其中过去的一次微类星体喷流活动注入了相对论性质子，这些质子目前处于遗迹阶段被观测到。方法。能量依赖的扩散自然地将粒子群分开：较低能量的质子被限制在致密分子气体附近，并解释了GeV发射，而较高能量的粒子到达更远的物质，产生硬的TeV-PeV成分。结果。对于代表性的星际条件，该模型同时与宽带谱能量分布、空间致密-延展二分性以及缺乏可探测的射电或X射线对应体相一致。结论。观测到的双峰伽马射线现象因此表现为单一注入质子群的输运效应，支持将LHAASO J2108+5157解释为处于中间演化阶段观测到的化石微类星体遗迹，并强调遗迹喷流系统作为银河系PeV加速器的一个可行类别。
英文摘要：
Context. LHAASO~J2108+5157 is one of the most intriguing Galactic ultra-high-energy $γ$-ray sources. It is detected up to hundreds of TeV but lacks a clear counterpart at lower frequencies. Fermi-LAT observations have revealed a compact GeV source spatially coincident with the PeV emission, while VERITAS and LST-1 impose stringent upper limits in the intermediate TeV band, producing a pronounced spectral suppression between the GeV and TeV domains. Aims. We investigate a time-dependent hadronic scenario in which a past episode of microquasar jet activity injected relativistic protons that are now observed in a relic phase. Methods. Energy-dependent diffusion naturally segregates the particle population: Lower-energy protons remain confined near dense molecular gas and account for the GeV emission, whereas higher-energy particles reach more distant material, producing the hard TeV--PeV component. Results. For representative interstellar conditions, the model is simultaneously consistent with the broadband spectral energy distribution, the spatial compact--extended dichotomy, and the lack of detectable radio or X-ray counterparts. Conclusions. The observed bimodal $γ$-ray phenomenology thus emerges as a transport effect of a single injected proton population, supporting the interpretation of LHAASO~J2108+5157 as a fossil microquasar remnant observed at an intermediate evolutionary stage and highlighting relic jet systems as a viable class of Galactic PeVatrons.
