论文标题
活性银河核中多个变化外观现象的可能机制
A possible mechanism for multiple changing look phenomenon in Active Galactic Nuclei
论文作者
论文摘要
现在在越来越多的活跃星系中观察到的更换现象挑战了我们对接近黑洞的积聚过程的理解。我们对观察到多个半周期爆发的来源提出了一个简单的解释，并且来源以爱丁顿限制的几％运行。爆发是由在标准气体主导的外盘和热光学薄内部对流主导的积聚流之间狭窄环中运行的辐射压力不稳定性引起的。相应的极限周期是导致周期性爆发的原因，并且由于不稳定的径向区域的狭窄，时间尺度比标准粘性时间尺度短得多。我们的玩具模型给出了定量预测，并且可以很好地适用于多次爆发，例如NGC 1566，NGC 4151，NGC 5548和GSN 069中观察到的爆发，尽管爆发的形状尚未很好地建模，并且需要进一步开发该模型。
Changing-look phenomenon observed now in a growing number of active galaxies challenges our understanding of the accretion process close to a black hole. We propose a simple explanation for the sources where multiple semi-periodic outbursts are observed, and the sources are operating at a few per cent of the Eddington limit. The outburst are caused by the radiation pressure instability operating in the narrow ring between the standard gas-dominated outer disk and the hot optically thin inner Advection-Dominated Accretion Flow. The corresponding limit cycle is responsible for periodic outbursts, and the timescales are much shorter than the standard viscous timescale due to the narrowness of the unstable radial zone. Our toy model gives quantitative predictions and works well for multiple outbursts like those observed in NGC 1566, NGC 4151, NGC 5548 and GSN 069, although the shapes of the outbursts are not yet well modeled, and further development of the model is necessary.
