发表机构
INAF-IAPS; INAF-OAS（意大利国家天体物理研究所-国际天体物理中心; 意大利国家天体物理研究所-天文观测台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对银河系拍电子伏加速器源识别的关键问题，需专用兆电子伏特伽马射线观测任务填补现有观测缺口，以区分强子与轻子发射，明确宇宙射线加速起源。
AI 中文摘要
识别将银河系宇宙射线加速至拍电子伏能量的源仍是高能天体物理学领域的重大开放问题。高海拔宇宙线观测站（LHAASO）的最新观测已揭示出越来越多的银河系拍电子伏加速器候选体。然而，仅探测太电子伏特-拍电子伏伽马射线无法唯一确定发射粒子的性质，在许多情况下，强子和轻子情景都能重现观测到的甚高能发射，导致辐射起源无法确定。强子加速最可靠、模型依赖性最低的电磁示踪剂由中性π介子衰变提供，其在10-100兆电子伏特能量范围内产生特征性的π介子峰。因此，该能段的观测对于确定候选拍电子伏加速器是否在加速质子和原子核、进而评估它们在银河系宇宙射线起源中的作用至关重要。更广泛地说，兆电子伏特领域解决关键天体物理问题，但仍是电磁频谱中探索最少的区域之一。随着当前和未来甚高能设备扩大银河系拍电子伏普查，兆电子伏特观测的缺失正成为源识别的主要限制。我们讨论了针对π介子峰研究优化的专用兆电子伏特伽马射线能力的天体物理科学驱动因素和观测要求，探索了一种紧凑、聚焦且可能快速推进的任务概念，该任务能够在开发和评估更雄心勃勃的下一代兆电子伏特设施之际，填补即将到来的兆电子伏特观测缺口。此类任务将提供区分强子和轻子发射所需的缺失诊断，识别银河系宇宙射线加速器，并充分利用新兴一代太电子伏特观测站的科学回报。
英文摘要
The identification of the sources responsible for accelerating Galactic cosmic-rays up to PeV energies remains a major open question in high-energy astrophysics. Recent observations by the Large High Altitude Air Shower Observatory (LHAASO) have revealed a growing population of Galactic PeVatron candidates. However, the detection of TeV-PeV gamma-rays alone does not uniquely identify the nature of the emitting particles. In many cases, both hadronic and leptonic scenarios can reproduce the observed very-high-energy emission, leaving the origin of the radiation unresolved. The most robust and least model-dependent electromagnetic tracer of hadronic acceleration is provided by neutral-pion decay, which produces the characteristic pion bump in the 10-100 MeV energy range. Observations in this energy band are therefore essential to establish whether candidate PeVatrons are accelerating protons and nuclei and, consequently, to assess their role in the origin of Galactic cosmic-rays. More broadly, the MeV domain addresses key astrophysical questions, but remains one of the least explored regions of the electromagnetic spectrum. As current and future VHE facilities expand the Galactic PeVatron census, the lack of MeV observations is becoming a major limitation for source identification. We discuss the astrophysical science drivers and observational requirements for a dedicated MeV gamma-ray capability optimized for pion-bump studies. We explore the concept of a compact, focused, and potentially fast-track mission capable of filling the impending MeV observational gap while more ambitious next-generation MeV facilities are developed and evaluated. Such a mission would provide the missing diagnostic needed to distinguish hadronic and leptonic emission, identify Galactic cosmic-ray accelerators, and fully exploit the scientific return of the emerging generation of TeV observatories.
Comments15 pages, 4 figures, SPIE Proceedings Astronomical Telescope + Instrumentation 2026: Ultraviolet to Gamma-rays Conference, Copenhagen, 5-10 July 2026
Journal refM. Cardillo, R. Campana, Y. Evangelista, and F. Muleri, Proc. SPIE 14146, 141465D (2026)
