论文标题
OJ 287的时间和光谱变化在4月至6月2020年爆发之前
Temporal and Spectral Variability of OJ 287 before the April--June 2020 Outburst
论文作者
论文摘要
We present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by Swift satellite during September 2019--March 2020. In this period, the source showed moderate variability characterized by variability amplitude of $\sim$22--31% in all the wavelengths on a short timescale, except the hard X-ray band which was variable by only $ \ sim $ 8％。我们观察到，源的X射线通量由低于$ 2 $ KEV的软光子显着控制。在光学/紫外线和软X射线排放之间检测到$ \ sim $ 45天的软滞后，而硬X射线与较低的能带之间没有相关性，表明存在两个发射成分或电子群体。尽管两个组件有助于X射线发射，但大多数0.3--10 KEV光谱中的大多数都配备了吸收的幂律模型，该模型概述了同步器在逆Compton（IC）机制上的优势。 X射线光谱遵循较弱的“较亮”趋势。
We present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by Swift satellite during September 2019--March 2020. In this period, the source showed moderate variability characterized by variability amplitude of $\sim$22--31% in all the wavelengths on a short timescale, except the hard X-ray band which was variable by only $\sim$8%. We observed that the X-ray flux of the source was significantly dominated by the soft photons below $2$ keV. Soft lags of $\sim$45 days were detected between the optical/UV and soft X-ray emissions, while there is no correlation between the hard X-rays and the lower energy bands indicating the presence of two emission components or electron populations. Although two components contribute to the X-ray emission, most of the 0.3--10 keV spectra were well fitted with an absorbed power-law model which outlines the dominance of synchrotron over inverse Compton (IC) mechanism. The X-ray spectra follow a weak "softer when brighter" trend.
