Blazar variability appears to be stochastic in nature. However, a possibility of low-dimensional chaos was considered in the past, but with no unambiguous detection so far. If present, it would constrain the emission mechanism by suggesting an underlying dynamical system. We rigorously searched for signatures of chaos in Fermi-Large Area Telescope light curves of 11 blazars. The data were comprehensively investigated using the methods of nonlinear time-series analysis: phase-space reconstruction, fractal dimension, and maximal Lyapunov exponent (mLE). We tested several possible parameters affecting the outcomes, in particular the mLE, in order to verify the spuriousness of the outcomes. We found no signs of chaos in any of the analysed blazars. Blazar variability is either truly stochastic in nature or governed by high-dimensional chaos that can often resemble randomness.

中文翻译：

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在选定的 Fermi-LAT 耀变体的 γ 射线光曲线中寻找混沌特征

耀变体的变异性在本质上似乎是随机的。然而，过去曾考虑过低维混沌的可能性，但到目前为止还没有明确的检测。如果存在，它将通过暗示一个潜在的动力系统来限制发射机制。我们在 11 个耀变体的费米大面积望远镜光变曲线中严格寻找混沌特征。使用非线性时间序列分析方法对数据进行了综合研究：相空间重建、分形维数和最大李雅普诺夫指数（mLE）。我们测试了影响结果的几个可能参数，特别是 mLE，以验证结果的虚假性。我们在任何分析过的耀变体中都没有发现混乱的迹象。