论文标题
PKS 1502+106的曲率诱导极化和光谱指数行为
Curvature induced polarization and spectral index behavior for PKS 1502+106
论文作者
论文摘要
对多频相关性的全面研究可以阐明Blazars变异的性质。在这项工作中，我们收集了PKS 1502+106的长期无线电，光学和$γ$ -Ray的光曲线。在执行了局部互相关函数分析之后，我们发现无线电和$γ$ ray或$ v $ band之间的相关性超出了$3σ$的显着性水平。相对于15 GHz的$γ$ ray的滞后是$ -60^{+5} _ { - 10} $ days，转化为$ 3.18^{+0.50} _ { - 0.27} $ parsec（pc）。在不确定性中，$γ$ ray和光学发射区域的位置大致相同，并且在$ 1.2 $ PC的范围内远离喷气基地。光学和$γ$ ray发射区域中的衍生磁场约为$ 0.36 $ g。$γ$ - ray磁通的对数与$ v $ band Fluxes的频率与$ V $ band Fluxes的相关性显着相关，可以通过Synchrotron Self-Compton（SSC）进程，外部compton（ec）（ec）的流量来解释。我们发现$ \ log \ prod $（偏振度）与$ v $ band的$ \ loglogνf_ν$的图中有显着的线性相关性，并使用经验关系$π\ sim \ sin \ sin \ sin^nθ'$（$θ'$（$θ'$是在集中框架中观察的角度）来解释它。颜色索引的行为（通常在活动状态更明亮时变红）和$γ$ -Ray光谱指数（较亮时较轻）可以通过扭曲的喷气模型很好地解释。这些发现表明，在PKS 1502+106的通量，光谱指数和极化度的变化现象中，曲率效应（主要是由于观看角的变化）主要是在主导的。
A comprehensive study of multifrequency correlations can shed light on the nature of variation for blazars. In this work, we collect the long-term radio, optical and $γ$-ray light curves of PKS 1502+106. After performing the localized cross-correlation function analysis, we find that correlations between radio and $γ$-ray or $V$ band are beyond the $3σ$ significance level. The lag of the $γ$-ray relative to 15 GHz is $-60^{+5}_{-10}$ days, translating to a distance $3.18^{+0.50}_{-0.27}$ parsec (pc) between them. Within uncertainties, the locations of the $γ$-ray and optical emitting regions are roughly the same, and are away from the jet base within $1.2$ pc. The derived magnetic field in optical and $γ$-ray emitting regions is about $0.36$ G. The logarithm of $γ$-ray flux is significantly linearly correlated with that of $V$ band fluxes, which can be explained by the synchrotron self-Compton (SSC) process, the external Compton (EC) processes, or the combination of them. We find a significant linear correlation in the plot of $\log\prod$ (polarization degree) versus $\log νF_ν$ at $V$ band, and use the empirical relation $Π\sim \sin^n θ'$ ($θ'$ is the observing angle in the comoving frame blob) to explain it. The behaviors of color index (generally redder when brighter at the active state) and $γ$-ray spectral index (softer when brighter) could be well explained by the twisted jet model. These findings suggest that the curvature effect (mainly due to the change of the viewing angle) is dominant in the variation phenomena of fluxes, spectral indices, and polarization degrees for PKS 1502+106.
