Radiative signatures of plasmoid-dominated reconnection in blazar jets
Radiative signatures of plasmoid-dominated reconnection in blazar jets
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DOI：
10.1093/mnras/sty2636
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发表时间：
2018-07
影响因子：
4.8
通讯作者：
I. Christie;M. Petropoulou;L. Sironi;D. Giannios
中科院分区：
文献类型：
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作者：
I. Christie;M. Petropoulou;L. Sironi;D. Giannios
在耀变体中观测到的多波长光谱和时间变化对当前的理论发射模型设置了严格的约束。在这里，我们调查的相对论磁场重联过程作为耀变体发射源，其中准球形等离子体团，包含相对论粒子和磁场，与耀变体喷流中的发射站点。通过耦合最近的二维粒子在细胞模拟的相对论重联与时间相关的辐射传输代码，我们计算的非热发射从一个链的等离子体团形成在重联事件。导出的光子谱显示在BL Lac源和平坦谱射电类星体中观察到的特征，通过改变外部光子场的强度，射流磁化强度和每个质子的数量对内所包含的区别。由重联事件产生的光变曲线由许多快速而强大的耀斑组成，这些耀斑出现在由中等大小等离子体团累积发射产生的缓慢演变的包络线上。所观察到的变化是高度依赖于重联层相对于耀变体喷流轴和观察者的取向。我们的模型提供了一个物理动机的框架来解释多时间尺度的耀变体在整个电磁频谱。
The multi-wavelength spectral and temporal variability observed in blazars set tight constraints on current theoretical emission models. Here, we investigate the relativistic magnetic reconnection process as a source of blazar emission in which quasi-spherical plasmoids, containing relativistic particles and magnetic fields, are associated with the emission sites in blazar jets. By coupling recent two-dimensional particle-in-cell simulations of relativistic reconnection with a time-dependent radiative transfer code, we compute the non-thermal emission from a chain of plasmoids formed during a reconnection event. The derived photon spectra display characteristic features observed in both BL Lac sources and flat spectrum radio quasars, with the distinction made by varying the strength of the external photon fields, the jet magnetization, and the number of pairs per proton contained within. Light curves produced from reconnection events are composed of many fast and powerful flares that appear on excess of a slower evolving envelope produced by the cumulative emission of medium-sized plasmoids. The observed variability is highly dependent upon the orientation of the reconnection layer with respect to the blazar jet axis and to the observer. Our model provides a physically motivated framework for explaining the multi-timescale blazar variability across the entire electromagnetic spectrum.