发表机构
School of Physics and Electrical Engineering, Liupanshui Normal University; Department of Physics, Yunnan Normal University; Department of Astronomy, School of Physics, Huazhong University of Science and Technology（六盘水师范学院物理与电气工程学院; 云南师范大学物理系; 华中科技大学物理学院天文学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用费米LAT约16.5年数据，在耀变体4FGL J1754.2+3212的GeV谱中发现31 GeV处约3σ的线状过剩，可能源于暗物质或轴子类粒子，挑战传统单区喷流模型，需VLAST等下一代仪器验证。
AI 中文摘要
我们报告了使用费米大面积望远镜约16.5年的观测数据，在耀变体4FGL J1754.2$+$3212的GeV伽马射线谱中探测到一个试探性的窄谱特征。对时间平均谱的详细似然分析揭示了一个位于$\sim$31 GeV能量处的局域线状过剩，其局部统计显著性为$\sim$3$\sigma$（3个自由度），未进行多重试验和look-elsewhere效应修正。该特征无法用标准平滑连续谱模型（如单一对数抛物线）很好地描述。添加一个高斯分量可显著改善谱拟合。如果未来更高灵敏度的观测证实这一特征，它将代表耀变体天体物理学中的一种新颖现象。我们探讨了其可能的物理起源，可能涉及暗物质湮灭或光子-轴子类似粒子振荡等奇异过程，或结构化喷流内的极端天体物理机制。无论其最终性质如何，这一发现凸显了对耀变体进行深度谱研究以揭示非标准物理的潜力，并对传统单区发射模型提出了挑战。最终验证有待下一代仪器，特别是甚大面积$\gamma$射线空间望远镜（VLAST）的观测。
英文摘要
We report the detection of a tentative, narrow spectral feature in the GeV gamma-ray spectrum of the blazar 4FGL J1754.2$+$3212, using approximately 16.5 years of observations from the Fermi Large Area Telescope. A detailed likelihood analysis of the time-averaged spectrum reveals a localized, line-like excess at an energy of $\sim$31 GeV, with a local statistical significance of $\sim$3$σ$ (3 degrees of freedom), without corrections for multiple trials and the look-elsewhere effect. This feature is not well described by standard smooth continuum models such as a single log-parabola. The addition of a Gaussian component significantly improves the spectral fit. If confirmed by future observations with higher sensitivity, this feature would represent a novel phenomenon in blazar astrophysics. We explore its potential physical origins, which could involve exotic processes such as dark matter annihilation or photon-axion-like-particle oscillations, or extreme astrophysical mechanisms within a structured jet. Regardless of its ultimate nature, this finding highlights the potential of deep spectral studies of blazars to reveal non-standard physics and challenges conventional one-zone emission models. Definitive verification awaits observations by next-generation instruments, particularly the Very Large Area $γ$-ray Space Telescope (VLAST).
Comments8 pages, 3 figures, 1 table, Comments are welcome!
