Long-term optical and X-ray variability of the Seyfert galaxy Markarian 79
Long-term optical and X-ray variability of the Seyfert galaxy Markarian 79
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DOI：
10.1111/j.1365-2966.2008.14302.x
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发表时间：
2008-12
影响因子：
4.8
通讯作者：
E. Breedt;P. Ar'evalo;I. McHardy;P. Uttley;S. Sergeev;T. Minezaki;Y. Yoshii;C. Gaskell;E. Cackett
中科院分区：
文献类型：
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作者：
E. Breedt;P. Ar'evalo;I. McHardy;P. Uttley;S. Sergeev;T. Minezaki;Y. Yoshii;C. Gaskell;E. Cackett
我们提出的结果，同时X射线和光学监测的塞弗特1星系Mrk 79超过5年的时间。我们发现，在短到中等的时间尺度（几天到几十天）的2-10千电子伏的X射线和光学u-和V-波段通量显着相关，与0 d一致的带之间的延迟。我们表明，这些变化中的大多数可以很好地再现的模型，其中的短期光学变化源于再处理的X射线的光学厚吸积盘。然而，光学光变曲线也显示了数千天的长时间尺度变化，这在X射线光变曲线中不存在。这些光学变化必须起源于一个独立的可变性机制，我们表明，它们可以产生的（几何）薄盘吸积率的变化，以及通过改变再处理分数通过改变X射线日冕的位置。
We present the results of concurrent X-ray and optical monitoring of the Seyfert 1 galaxy Mrk 79 over a period of more than 5 yr. We find that on short to medium time-scales (days to a few tens of days) the 2–10 keV X-ray and optical u- and V-band fluxes are significantly correlated, with a delay between the bands consistent with 0 d. We show that most of these variations may be well reproduced by a model where the short-term optical variations originate from reprocessing of X-rays by an optically thick accretion disc. The optical light curves, however, also display long time-scale variations over thousands of days, which are not present in the X-ray light curve. These optical variations must originate from an independent variability mechanism and we show that they can be produced by variations in the (geometrically) thin disc accretion rate as well as by varying reprocessed fractions through changes in the location of the X-ray corona.