低峰频blazars的射电光变分析

The Analysis of the Radio Light Curves of Low-peak Frequency Blazars

从大量文献资料中收集了6个低峰频blazars(BL Lacertae、0235+164、OQ530、0716+714、3C 345及3C 273)最近30多年来在4.8 GHz、8 GHz、14.5 GHz、22GHz和37 GHz最完备的光变数据.利用离散相关函数法对这6个源的相关性及延迟进行分析,利用结构函数法对6个源的光变曲线的光变周期和光变时标进行分析并对其光变幅度进行比较分析.分析结果显示:在光变幅度方面,0716+714和0235+164在6个blazars中的光变幅度相对较大,3C 345和OQ 530次之,3C 273和BL Lacertae的光变幅度相对较小;多波段的延迟分析显示0235+164在相邻两波段之间都显示高频波段要超前于低频波段的变化趋势,3C 345整体呈现出高频波段滞后于低频波段的变化趋势.其余blazars分析结果显示在部分射电波段之间呈现出高频波段要超前于低频波段的变化趋势,而在其余射电波段之间却呈现出高频波段滞后于低频波段的变化趋势;结构函数法的分析结果显示3C 345的光变时标、拟合斜率及光变周期与其它5个低峰频blazars相比都偏大,这表明3C 345的活动性与其它5个源相比较弱,这表明在3C 345内部可能存在与其它5个低峰频blazars不同的物理过程.

From a large amount of literatures, we have collected a large number of light curve data of BL Lacertae, 0235＋164, OQ 530, 0716＋714, 3C 345, and 3C 273 in 4.8 GHz, 8 GHz, 14.5 GHz, 22 GHz, and 37 GHz for more than 30 years. The correlation and time delay have been investigated with the discrete correlation function method. The light curve period and timescale have been analyzed with the structure function method. It is shown from the analytical results that for the fractional variability amplitudes of these six blazars, 0716＋714 and 0235＋164 have the largest, 3C 345 and OQ 530 come second, and 3C 273 and BL Lacertae have the smallest. The light curve in the high frequency leads that in the low frequency for 0235＋164, and conversely for 3C 345. For the other blazars, the above two situations both exist. The results from the structure function method show that the variability timescale, the fitting slope, and the variability period of 3C 345 are larger than those of the other five blazars, respectively. This may indicates that there are different physical processes in 3C 345.