Long-term and multiwavelength evolution of a changing-look AGN Mrk 1018
Long-term and multiwavelength evolution of a changing-look AGN Mrk 1018
复制标题
外观不断变化的 AGN Mrk 1018 的长期多波长演化
DOI：
10.1093/mnras/stab1581
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发表时间：
2021
影响因子：
4.8
通讯作者：
Qingwen Wu
中科院分区：
文献类型：
--
作者：
Bing Lyu;Zhen Yan;Wenfei Yu;Qingwen Wu
摘要。触发活动星系核变貌现象的物理机制至今仍不清楚。我们探讨这个问题的基础上，在X射线，光学/紫外线（UV）和无线电波段的长期观测的变化看AGN Mrk 1018的多波长光谱和通量的变化。在2010-2015年期间，光学和X射线发射都经历了一个快速的变化相位衰减，其中在光学/紫外和X射线波段出现了再耀斑。我们发现在1.9型相位中，X射线变化背后的光学/UV的时间滞后为1.20 d。在2016-2017年期间，5 GHz无线电通量在1.9型阶段减少了20%。我们发现X射线光子指数（Γ）和光-X射线光谱指数（αox）都与1.9型相的2-10 keV Eddington标度X射线光度（LX/LEdd）有很好的相关性。而1型相偏离了这两个位相关系，这表明宽谱线的变化可能受吸积盘演化（如1.9型相内冷盘的消失）的控制。
ABSTRACT. The physical mechanism for triggering the changing-look phenomenon in active galactic nuclei (AGNs) is still unclear. We explore this issue based on the multiwavelength spectral and flux variations for a changing-look AGN Mrk1018 with long-term observations in the X-ray, optical/ultraviolet (UV), and radio bands. Both the optical and the X-ray emission experience a rapid decay in changing-look phase during 2010–2015, where a re-flare appears in the optical/UV and X-ray bands. We find a time lag of ∼20 d of optical/UV behind X-ray variations in type 1.9 phase. The 5 GHz radio flux decreases by ∼20 per cent in type 1.9 phase during 2016–2017. We find that both the X-ray photon index (Γ) and the optical-to-X-ray spectral index (αox ) are anticorrelated with the Eddington scaled 2–10 keV X-ray luminosity (LX/LEdd) in the type 1.9 phase. However, the type 1 phase deviates from these two anticorrelations, which suggests that the change of broad emission lines might be regulated by the evolution of accretion disc (e.g. disappearing of the inner cold disc in the type 1.9 phase).