标题： 2013年12月3C 279的强伽马射线耀斑 显示英文标题

标题： A hard gamma-ray flare from 3C 279 in 2013 December

摘要： 耀变体 3C 279 在 2013 年 12 月和 2014 年 4 月展示了两次强度相似的$\gamma$射线耀发。 在这项工作中，我们详细分析了 2013 年 12 月耀发事件的多波段特性。 多频观测揭示了 X 射线和光学-紫外流量峰值滞后于$\gamma$射线最大值的非相关变化模式。 $\gamma$射线活动峰值时的宽带谱能量分布 (SED) 显示出上升的$\gamma$射线光谱但下降的光学-紫外流量。 这一观测结果结合未关联变化行为的检测排除了一区电子发射情景的可能性。 因此，我们采用了两种独立的方法来解释 SED：时间相关的电子强子建模和两区电子辐射建模方法。 在电子强子建模中，受随机取向磁场影响的电子和质子分布产生同步辐射。 电子同步辐射用于解释红外到紫外辐射，而质子同步辐射则用于解释高能$\gamma$射线辐射。 后期阶段耀发期间观察到的 X 射线谱断点通过电子同步自康普顿辐射与质子同步辐射的组合来解释。 在两区建模中，我们假设主要在红外到 X 射线以及$\gamma$射线区域发射的大型发射区主要来自快速移动的紧凑发射区。 最后，我们指出，在短短 4 个月内，3C 279 展示了各种辐射过程之间的主导性，这反映了理解耀变体喷流物理特性的复杂性。 显示英文摘要

摘要： The blazar 3C 279 exhibited twin $\gamma$-ray flares of similar intensity in 2013 December and 2014 April. In this work, we present a detailed multi-wavelength analysis of the 2013 December flaring event. Multi-frequency observations reveal the uncorrelated variability patterns with X-ray and optical-UV fluxes peaking after the $\gamma$-ray maximum. The broadband spectral energy distribution (SED) at the peak of the $\gamma$-ray activity shows a rising $\gamma$-ray spectrum but a declining optical-UV flux. This observation along with the detection of uncorrelated variability behavior rules out the one-zone leptonic emission scenario. We, therefore, adopt two independent methodologies to explain the SED: a time dependent lepto-hadronic modeling and a two-zone leptonic radiative modeling approach. In the lepto-hadronic modeling, a distribution of electrons and protons subjected to a randomly orientated magnetic field produces synchrotron radiation. Electron synchrotron is used to explain the IR to UV emission while proton synchrotron emission is used to explain the high energy $\gamma$-ray emission. A combination of both electron synchrotron self Compton emission and proton synchrotron emission is used to explain the X-ray spectral break seen during the later stage of the flare. In the two-zone modeling, we assume a large emission region emitting primarily in IR to X-rays and $\gamma$-rays to come primarily from a fast moving compact emission region. We conclude by noting that within a span of 4 months, 3C 279 has shown the dominance of a variety of radiative processes over each other and this reflects the complexity involved in understanding the physical properties of blazar jets in general.