发表机构
Institute of High Energy Physics, Chinese Academy of Sciences; University of Chinese Academy of Sciences; Tianfu Cosmic Ray Research Center; University of Science and Technology of China; Yerevan State University; Max-Planck-Institut for Nuclear Physics; Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University; Center for Astrophysics, Guangzhou University(中国科学院高能物理研究所; 中国科学院大学; 天府宇宙线研究中心; 中国科学技术大学; 埃里温国立大学; 马克斯·普朗克核物理研究所; 上海交通大学李政道研究所与物理天文学院; 广州大学天体物理中心)
机构由 AI 辅助整理,请以论文原文为准。AI 中文总结
LHAASO-WCDA 观测到 blazar 1ES 1959+650 存在约5天的 TeV 延迟耀发,其TeV辐射滞后于GeV,该延迟无法用纯冷却机制解释,或与粒子加速、输运有关,当前数据未明确机制。
AI 中文摘要
我们报告了2024年初HBL 1ES~1959+650的GeV和TeV伽马射线辐射之间存在天量级的硬延迟。自LHAASO-WCDA实时监测系统于2023年底投入运行以来,已触发该源的多次TeV耀发,包括2024年2月9日的首次触发耀发。对WCDA光变曲线的贝叶斯分块分析识别出2024年的三次TeV耀发。针对第二次触发耀发,离散互相关分析显示,相对于不相关红噪声模拟,在时间延迟Δt=5.0_{-2.1}^{+2.1}天处存在大于3σ的相关性,即TeV辐射滞后于GeV。时间分辨光谱学表明,该耀发是这些耀发中TeV谱最软的(本征谱指数Γ=3.16±0.18),而首次触发耀发谱更硬(Γ=2.48±0.21)。观测到的5天硬延迟难以与纯冷却驱动的时间序调和,符合粒子加速和/或输运可能对演化有贡献的情景,但当前数据无法唯一确定潜在机制。
英文摘要
We report a day-scale hard lag between GeV and TeV $γ$-ray emission from the HBL 1ES~1959+650 in early 2024. Since the LHAASO-WCDA real-time monitoring system began operation in late 2023, multiple TeV flares from this source have been triggered, including the 1st trigger flare on 2024 February 9. A Bayesian-block analysis of the WCDA light curve identifies three TeV flares in 2024. For the second triggered flare, a discrete cross-correlation analysis reveals a $>3\,σ$ correlation (relative to uncorrelated red-noise simulations) at a time delay of $Δt = 5.0_{-2.1}^{+2.1}$ days, with the TeV emission lagging the GeV. Time-resolved spectroscopy shows that this flare has the softest TeV spectrum among these flares (intrinsic spectral index $Γ=3.16\pm0.18$), while the 1st trigger flare is harder ($Γ=2.48\pm0.21$). The observed five-day hard lag is difficult to reconcile with a purely cooling-driven temporal ordering and is consistent with scenarios in which particle energization and/or transport may contribute to the evolution. However, the current data do not uniquely identify the underlying mechanism.
Comments15 pages,5 figures