Multi-band optical variability of BL Lac object OQ 530  

作　　者：Bing-Kai Zhang Ben-Zhong Dai Li Zhang Zhen Cao 

机构地区：[1]Department of Physics, Fuyang Normal College, Fuyang 236041, China [2]Department of Physics, Yunnan University, Kunming 650091, China [3]Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Research in Astronomy and Astrophysics》2010年第7期653-662,共10页天文和天体物理学研究（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 10975145);funded by Fuyang Normal College, the Research Foundation of the Department of Education of Anhui Province (KJ2010B159)

摘　　要：Historical optical data are combined on the BL Lac object OQ 530. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate emission processes. To examine the possible existence of a lag between variations in different optical bands from this source, a statistical analysis is performed through the discrete correlation function （DCF） method and the z-transformed discrete correlation function （ZDCF） method. Monte Carlo simulations called ＂flux redistribution/random subset selection＂ （FR/RSS） are performed to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties. The analysis confirms that the variations in different optical light curves are strongly correlated, with zero-lag within the errors. Long term variability of color indexes is also analyzed. The result suggests a strong correlation between color index and brightness. A clear bluer-when-brighter chromatism is found, in the sense that the spectrum steepens as the brightness decreases.Historical optical data are combined on the BL Lac object OQ 530. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate emission processes. To examine the possible existence of a lag between variations in different optical bands from this source, a statistical analysis is performed through the discrete correlation function （DCF） method and the z-transformed discrete correlation function （ZDCF） method. Monte Carlo simulations called ＂flux redistribution/random subset selection＂ （FR/RSS） are performed to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties. The analysis confirms that the variations in different optical light curves are strongly correlated, with zero-lag within the errors. Long term variability of color indexes is also analyzed. The result suggests a strong correlation between color index and brightness. A clear bluer-when-brighter chromatism is found, in the sense that the spectrum steepens as the brightness decreases.

关 键 词：BL Lacs general -- BL Lacs individual （OQ 530） 

分 类 号：TP342[自动化与计算机技术—计算机系统结构] X87[自动化与计算机技术—计算机科学与技术]