Violent multi-wavelength variabilities are observed in gamma-ray-selected blazars. We present an analysis of long-term light curves for eight bright blazars to explore the co-variation pattern in the gamma-ray and radio bands. We extract their gamma-ray light curves and spectra with data observed by the Fermi/LAT since 2008. We find diverse co-variation patterns between the gamma-ray and radio (at 43 GHz) fluxes in these sources. The gamma-ray and radio fluxes of 3C 454.3 and PKS 1633+382 are correlated without any time-lag, suggesting that they are from the same radiation region. Similar correlation is also observed in 3C 273 and PKS 1222+216, but the radio flux is lag behind the gamma-ray flux approximately ~160 days and ~290 days, respectively. This likely suggests that their gamma-ray emission regions are located at the upstream of their radio cores at 43 GHz. The gamma-ray and radio fluxes of the other four blazars are not correlated, implying that the gamma-ray and radio emission may be from different regions in their jets. The gamma-ray light curves of the eight blazars can be decomposed into some long timescale variability components and fast spike flares. We propose that they may be attributed to the central engine activity and the magnetic reconnection process or turbulence in the local emission region, respectively.

中文翻译：

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明亮耀变体的 γ 射线和无线电变异性的多样性以及对 γ 射线发射位置的影响

在伽马射线选择的耀变体中观察到剧烈的多波长变异。我们对八个明亮耀变体的长期光变曲线进行了分析，以探索伽马射线和无线电波段的共变模式。我们使用费米/LAT 自 2008 年以来观测到的数据提取了它们的伽马射线光曲线和光谱。我们发现这些源中的伽马射线和无线电（43 GHz）通量之间存在多种协变模式。3C 454.3 和 PKS 1633+382 的伽马射线和无线电通量相互关联，没有任何时滞，表明它们来自同一辐射区域。在 3C 273 和 PKS 1222+216 中也观察到了类似的相关性，但无线电通量分别落后于伽马射线通量约约 160 天和约 290 天。这可能表明它们的伽马射线发射区域位于 43 GHz 无线电核心的上游。其他四个耀变体的伽马射线和无线电通量没有相关性，这意味着伽马射线和无线电发射可能来自它们喷流的不同区域。八个耀变体的伽马射线光变曲线可以分解为一些长时间尺度的可变性分量和快速尖峰耀斑。我们提出它们可能分别归因于中央发动机活动和局部排放区域的磁重联过程或湍流。八个耀变体的伽马射线光变曲线可以分解为一些长时间尺度的可变性分量和快速尖峰耀斑。我们提出它们可能分别归因于中央发动机活动和局部排放区域的磁重联过程或湍流。八个耀变体的伽马射线光变曲线可以分解为一些长时间尺度的可变性分量和快速尖峰耀斑。我们提出它们可能分别归因于中央发动机活动和局部排放区域的磁重联过程或湍流。