PKS 1424-418 中重复出现的双峰 γ 射线亚耀斑
Recurrent double-peaked $γ$-ray sub-flares in PKS 1424-418
- Xiamen University（厦门大学）
- National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究在PKS 1424-418的两个活跃时期发现重复双峰γ射线亚耀斑，峰间距约11.8天，间隔约67天，提出扰动穿过准静止再准直激波链的结构化喷流模型来解释该现象。
AI中文摘要：
我们报告了在 PKS 1424-418 中两个相似的主要活跃时期（MJD 56117--56498 和 MJD 59669--59978）内，γ 射线亚耀斑出现重复双峰结构的迹象。候选的双峰亚耀斑表现出特征性的亚耀斑内峰间距约为 11.8 天，以及相邻亚耀斑间隔约为 67 天。红噪声蒙特卡洛检验表明，仅凭随机变异性难以重现这种候选的重复双峰形态，两个活跃时期的误报概率分别为 p_a=0.0216 和 p_b=0.0006。在整个费米大面积望远镜（LAT）光变曲线的模拟中，没有任何红噪声实现能够同时重现两个类似时期的特征。光谱能量分布（SED）建模显示，一个双峰候选体的两个峰具有相似辐射特性，而多普勒因子的变化似乎在耀斑活动中起着重要作用。结合先前报道的毫米波与 γ 射线发射之间近乎零的延迟，这些结果表明，这种重复活动可能与致密的毫米/亚毫米核区有关。我们讨论了一种可能的喷流结构场景，其中单一扰动穿过一系列准静止的再准直激波传播。在这种图像中，扰动与激波结构之间的重复相互作用可能定性地解释双峰亚耀斑轮廓以及观测到的约 11.8 天和约 67 天的时间尺度。需要进一步的活跃时期来确定这种相似性是否代表一种重复的长期行为。
英文摘要：
We report a hint of recurrent double-peaked $γ$-ray sub-flares in PKS~1424--418 during two similar major active epochs, MJD 56117--56498 and MJD 59669--59978. The candidate double-peaked sub-flares show a characteristic intra-subflare peak separation of $\sim 11.8$ d and a neighbouring-subflare spacing of $\sim 67$ d. Red-noise Monte Carlo tests indicate that the candidate recurrent double-peaked morphology is not easily reproduced by stochastic variability alone, with false-alarm probabilities of $p_{\rm a}=0.0216$ and $p_{\rm b}=0.0006$ for the two active epochs, respectively. In the simulations of the entire \textit{Fermi} Large Area Telescope (LAT) light curve, no red-noise realisation reproduces both epoch-like structures. The spectral energy distribution (SED) modelling shows similar radiative properties for the two peaks of one double-peaked candidate, while changes in the Doppler factor appear to play an important role in the flaring activity. Together with the previously reported near-zero lag between the millimetre and $γ$-ray emission, these results suggest that the recurrent activity may be associated with the compact mm/sub-mm core region. We discuss a possible structured-jet scenario in which a single disturbance propagates through a chain of quasi-stationary recollimation shocks. In this picture, repeated interactions between the disturbance and the shock structure may qualitatively account for both the double-peaked sub-flare profiles and the observed $\sim 11.8$ d and $\sim 67$ d time-scales. Further active epochs are required to determine whether this similarity represents a recurrent long-term behaviour.
