Long-term optical and radio variability analysis of BL Lacertae 2200+420
نویسنده
چکیده
Based on the radio light curves in 22 GHz and 37 GHz from the Metsahovi monitoring program and the optical light curves in BVRI bands from previously published results and the “Whole Earth Blazar Telescope” (WEBT) archives, we analyze the time delay among 22 GHz, 37 GHz and optical bands (B, V, R, I) of BL Lacertae by means of discrete correlation method. The results suggest there exist strong correlation among 22 GHz, 37 GHz and optical bands (B, V, R, I) with zero-lag. The 37 GHz lags behind R band by 11 months. The correlation of brightness and color index among BVRI bands, brightness and spectral index between 37 GHz and 22 GHz are also investigated. The results show a clear trend of bluer-when-brighter.
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تاریخ انتشار 2013