Long-term optical spectra variability of BL Lacertae object OJ 287
Long-term optical spectra variability of BL Lacertae object OJ 287
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DOI：
10.1111/j.1365-2966.2008.12761.x
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发表时间：
2008-04
影响因子：
4.8
通讯作者：
Y. Zheng;Xiong Zhang;X. Bi;J. Hao;H. Zhang
中科院分区：
文献类型：
--
作者：
Y. Zheng;Xiong Zhang;X. Bi;J. Hao;H. Zhang
基于文献中的长期数据，我们提出了BL Lacertae天体oj287的长期光谱指数变化行为的证据。首先，我们发现BL Lacertae天体OJ 287的光谱指数变化周期与约11.96 yr的光通量变化周期是一致的，认为不同的过程引起了光谱的变化，每个过程在光谱指数中应该有明确的特征，从而导致了光谱指数的周期性。我们还发现光谱指数和光通量密度之间的时间滞后是光通量变化周期的一半。这个结果倾向于支持这样的论点，即当长期变化的亮度增加时，光谱变得更蓝。这些变化可以用爆发过程中电子的能量损失来解释。结果表明，在耀斑发生时，光谱指数与耀斑发生时不同；在超级耀斑的第一和第二耀斑峰之间，光谱形状是不同的。不同的过程可能诱发oj287的两个峰。
Based on the long-term data in the literature, we present evidence for long-term optical spectral index variability behaviour for BL Lacertae object OJ 287. First we find that the optical spectral index variability period of BL Lacertae object OJ 287 is in agreement with the optical flux variability period of about 11.96 yr. It is considered that different processes induce optical variability, and each process should have a definite signature in the spectral index, thus leading to the periodicity of the spectral index. We also find that the time lag between the optical spectral index and the optical flux density is half of the optical flux variability period. This result tends to support the argument that when the brightness of the long-term variations increases, the optical spectra become bluer. These variations can be explained by energy loss of the electrons during the outburst. We show that the spectral index is different during the flares compared with outside the flares; between the first and second flare peaks of the superflares, the spectrum shapes are different. Disparate processes possibly induce the two peaks of OJ 287.