Blazars represent dominant population of the extragalactic $\gamma$-ray sources in the Universe. These sources exhibit some characteristic properties like strong and non-thermal continuum emission over the entire electromagnetic spectrum from radio to TeV $\gamma$-rays with rapid variability on all timescales. The emission at radio and optical wavelengths is highly polarized with significant variation. The fastest variability in the blazar emission is observed during the flaring activity which is an important observational property of blazars. In this paper, we describe various methods to characterize the temporal variability in the multi-wavelength light curves of blazars. We also provide a detailed description of the set of statistical parameters which are used to quantify the level of variability present in the time-series. Implications of the informations derived from the variability study to probe the physics of blazars using multi-wavelength observations are also discussed.

中文翻译：

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耀变体光曲线变异性的表征

耀变体代表了宇宙中河外 $\gamma$ 射线源的主要群体。这些源表现出一些特性，例如在从无线电到 TeV $\gamma$ 射线的整个电磁频谱上的强和非热连续发射，在所有时间尺度上都具有快速变化。无线电和光波长的发射是高度极化的，变化很大。在耀斑活动期间观察到耀变体发射的最快变化，这是耀变体的一个重要观察特性。在本文中，我们描述了各种方法来表征耀变体多波长光变曲线的时间变化。我们还提供了一组统计参数的详细描述，这些参数用于量化时间序列中存在的可变性水平。