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arXiv · 1405.6858

Optical quasi-periodic oscillation and color behavior of blazar PKS 2155-304

Bing-Kai Zhang·Xiao-Yun Zhao·Chun-Xiao Wang·Ben-Zhong Dai
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Abstract

PKS 2155-304 is a well studied BL Lac object in the southern sky. The historical optical data during different period have been collected and compiled. Light curves with a time span of 35 years have been constructed. The R-band light curve has been analyzed by means of three methods: epoch folding method, Jurkevich method and discrete correlation function (DCF) method. It is derived that there is an evident periodic component of 317 days (i.e. 0.87 yr) superposed on a long-term trend with large-amplitude variation in the light curve. The variability of this source is accompanied by a slight color variation, and the brightness and color index are correlated with each other. On the long time-scale, PKS 2155-304 exhibits a tendency of bluer-when-brighter, which means the spectrum becomes flatter when the source brightens.

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Bing-Kai Zhang, Xiao-Yun Zhao, Chun-Xiao Wang, Ben-Zhong Dai. 2014-05-27. Optical quasi-periodic oscillation and color behavior of blazar PKS 2155-304. https://doi.org/10.1088/1674-4527/14/8/004

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