http://arxiv.org/abs/1707.03586
In the narrow-line Seyfert 1 galaxy Mrk 766, a Quasi-Periodic Oscillation (QPO) signal with a period of $\sim6450$ s is detected in the {\it XMM-Newton} data collected on 2005 May 31. This QPO signal is highly statistical significant at the confidence level of $>5.1\sigma$ with the quality factor of $Q=f/\triangle f>13.6$. The X-ray intensity changed by a factor of 3 with root mean square fractional variability of $14.3\%$. Furthermore, this QPO signal presents in the data of all three EPIC detectors and two RGS cameras and its frequency follows the $f_{\rm QPO}$-$M_{\rm BH}$ relation spanning from stellar-mass to supermassive black holes. Interestingly, a possible QPO signal with a period of $\sim4200$ s had been reported in the literature. The frequency ratio of these two QPO signals is $\sim$ 3:2. Our result is also in support of the hypothesis that the QPO signals can be just transient. The spectral analysis reveals that the contribution of the soft excess component below $\sim$ 1 keV is different between epochs with and without QPO, this property as well as the former frequency-ratio are well detected in X-ray BH binaries, which may have shed some lights on the physical origin of our event.
P. Zhang, P. Zhang, J. Yan, et. al.
Thu, 13 Jul 17
29/60
Comments: 7 pages, 4 figures
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