论文标题
磁通量倒置在奇特的变化外观Agn
Magnetic flux inversion in a peculiar changing look AGN
论文作者
论文摘要
我们认为，活性银河核1ES 1927+654中的变化外观事件，其次是X射线发光度中的3个数量级的下降量，由吸积率的变化和磁性停滞磁盘中磁通量的反转变化（疯狂）。在更换外观事件之前，黑洞上的强磁通量通过Blandford-Znajek工艺X射线发射，而紫外线发射是由辐射效率低下的磁化磁盘产生的。一个对流事件，带来了相反的极性的通量，首先向内引导紫外线/光学发光度，然后在X射线光度中浸入X射线亮度时，当它到达黑洞时。我们估计了磁通量对流的时间尺度，并发现更换外观事件的开始与X射线光度的最小值之间观察到的时间尺度（$ \ your \ of200 $ days）与消除磁通量在疯狂到$ \ $ \ your \ of to $ \ youty of180 \：r_g $中所需的时间一致。尽管由于所需的通量与质量的比例很高，但通量反转事件可能很少见，但我们认为AGN表现出异常高的X射线与紫外线光度比是此类事件的主要候选者。我们还建议类似的事件可能导致无线电大声对象中的喷气中断。
We argue that the changing-look event in the active galactic nucleus 1ES 1927+654, followed by a dip of 3 orders of magnitude in the X-ray luminosity, is controlled by a change in the accretion rate and an inversion of magnetic flux in a magnetically arrested disk (MAD). Before the changing-look event, strong magnetic flux on the black hole powers X-ray emission via the Blandford-Znajek process while the UV emission is produced by a radiatively inefficient magnetized disk. An advection event, bringing flux of the opposite polarity, propagates inward leading, first, to a rise in the UV/optical luminosity and, then, to a dip in the X-ray luminosity when it reaches the black hole. We estimate the timescale for magnetic flux advection and find that the observed timescale between the beginning of the changing-look event and the minimum in the X-ray luminosity, $\approx200$ days, is in agreement with the time needed to cancel the magnetic flux in a MAD extending to $\approx180\:r_g$. Although flux inversion events might be rare due to the large ratio of flux-to-mass that is needed, we argue that AGN showing an unusually high ratio of X-ray to UV luminosity are prime candidates for such events. We also suggest that similar events may lead to jet interruptions in radio-loud objects.
