2014/05/27 by Bing-Kai Zhang, Xiao-Yun Zhao, Chun-Xiao Wang +1 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Cosmic Phenomena #BL Lac object #Blazar #Brightness #Color index #Light curve #Neutrino Physics Research #Oscillation (cell signaling) #Variation (astronomy) #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.1088/1674-4527/14/8/004
9 pages, 4 figures. Accepted for publication in RAA (Research in Astronomy and Astrophysics)
arxiv created 2014/05/27 · openalex publication_date 2014/07/23 · arxiv updated 2015/06/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
PKS 2155–304 is a well studied BL Lac object in the southern sky. The historical optical data during different periods have been collected and compiled. Light curves spanning 35 yr have been constructed. The R -band light curve has been analyzed by means of three methods: the epoch folding method, the Jurkevich method and the discrete correlation function method. It is derived that there is an evident periodic component of 317 d (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 a long-term time scale, PKS 2155–304 exhibits a tendency of bluer-when-brighter, which means the spectrum becomes flatter when the source brightens.