Spectral-timing evidence for a very high state in the narrow-line Seyfert 1 Ark 564
Spectral-timing evidence for a very high state in the narrow-line Seyfert 1 Ark 564
复制标题
DOI：
10.1111/j.1365-2966.2006.10871.x
复制
发表时间：
2006-07
影响因子：
4.8
通讯作者：
P. Arévalo;I. Papadakis;P. Uttley;I. McHardy;W. Brinkmann
中科院分区：
文献类型：
--
作者：
P. Arévalo;I. Papadakis;P. Uttley;I. McHardy;W. Brinkmann
我们使用xmm -牛顿望远镜对窄线塞弗特1星系Ark 564进行了100公里长的观测，并将其与ASCA对同一源进行的长达一个月的监测相结合，计算了频率从~ 10 -6到10 - 3hz的不同能带之间的相位滞后和相干性。这是对任何活动星系核（AGN）精确计算出这些频谱时序特性的最宽频率范围。0.7-2 keV和2-10 keV的ASCA光曲线与相应能带的XMM-Newton光曲线在研究的大部分频率范围内具有高度相干（~ 0.9）。我们观察到能带之间的时间滞后，随着时间尺度和能带的能量分离而增加。时间滞后谱在10 -5到5 x 10 -4 Hz频率范围内显示一个宽峰，其中时间滞后遵循幂律斜率~ - 0.7。在~ 5 × 10 -4 Hz以上，滞后显著下降到此关系以下。这种斜率的变化类似于黑洞x射线双星（BHXRB）在非常高或中间状态下的滞后光谱的形状。滞后量随能带距离的对数线性增加，这使得该AGN与BHXRBs之间又多了一个相似之处。
We use a 100 ks long XMM-Newton observation of the narrow-line Seyfert 1 galaxy Ark 564 and combine it with the month-long monitoring of the same source produced by ASCA, to calculate the phase lags and coherence between different energy bands, over frequencies from ∼10 -6 to 10 -3 Hz. This is the widest frequency range for which these spectral-timing properties have been calculated accurately for any active galactic nuclei (AGN). The 0.7-2 and 2-10 keV ASCA light curves, and the XMM-Newton light curves in corresponding energy bands, are highly coherent (∼0.9) over most of the frequency range studied. We observe time lags between the energy bands, increasing both with time-scale and with energy separation of the bands. The time lag spectrum shows a broad peak in the 10 -5 to 5 x 10 -4 Hz frequency range, where the time lags follow a power-law slope ∼- 0.7. Above ∼5 x 10 -4 Hz the lags drop below this relation significantly. This change in slope resembles the shape of the lag spectra of black hole X-ray binaries (BHXRB) in the very high or intermediate state. The lags increase linearly with the logarithm of the separation of the energy bands, which poses one more similarity between this AGN and BHXRBs.