用小波分析方法计算BL Lac天体S5 0716+714的光变周期

Study the Optical Variability Periodicity for BL Lac Object S5 0716+714 by Wavelet Analysis Method

介绍了一种用小波分析寻找BL Lac天体S5 0716+714光变周期的方法.收集了BL Lac天体S5 0716+714光学B、V、R、I四个波段较完备的观测数据,获得了10天平均的长期光变曲线.使用此光变曲线数据进行小波分析计算,结果表明小波分析方法能较好地分析和认证BL Lac天体的光变周期值.从小波变换系数实部的等值线图,可以准确证认BL Lac天体S5 0716+714有光变周期波动变化.由B,V,R,I四个波段的小波方差曲线分析发现BL Lac天体S5 0176+714有一个1160天的稳定周期,这个结果与Raiteri等人发现的3.3年周期是一致的.预测在2011年8月将有一次大的爆发.

Using a wavelet analysis method, we studied periodicity of the optical variations for the BL Lac object S5 0716＋714 in this paper . By collecting a complete optical monitoring of the BL Lac object S5 0716＋714 in B, V, R and I bands, we got a long term light curve on 10 day baseline. The results showed that the wavelet analysis method is preferable in searching and identifying the periodical variations of BL Lac objects. From the contour map of the real part of the transformed coefficient, the results can exactly proof that there exists a optical variation of S5 0716＋714. By revisiting the wavelet variance curve in B, V, R and I bands, we were convinced that S5 0716＋714 has a stable periodicity on 1160 days. Such a conclusion is consistent with a 3.3 year period which was found by previous studies （Raiteri）. Therefore, it can be predicted that the next outburst should reach the brightness peak around 2011 August.