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arXiv 1607.01065astro-ph.HEastro-ph.GA
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对NGC 4051中的暖吸收器进行计时

Timing the warm absorber in NGC 4051

Catia Silva, Phil Uttley, Elisa Costantini

摘要:

我们调查,使用光谱定时分析,在塞弗特星系,所谓的温暖的吸收器的高度电离外流的特性。在这里,我们提出了我们的结果,广泛的~ 600 ks的XMM-牛顿档案观测的明亮和高度可变的塞弗特1星系NGC 4051,其光谱揭示了一个复杂的多组分风。利用RGS和EPIC-pn数据,我们进行了详细的分析,通过与时间相关的光电离代码结合光谱和傅立叶光谱定时技术。从数据中获得的源光变曲线和暖吸收体参数被用来模拟由于中心源的电离通量的变化的气体的响应。利用得到的时变光谱预测了热吸收体对光变曲线的时滞和相干性的影响。我们发现,在没有任何其他滞后机制的情况下,具有NGC 4051中观察到的特征的暖吸收体能够在~小时的时间尺度上产生高达100 s的软滞后。时间延迟与气体对电离源变化的响应有关,无论是通过光电离还是辐射复合,这取决于其密度。在我们的假设下,产生更长的时间延迟的径向距离范围与NGC 4051中温暖吸收体位置的现有估计相当。出于这个原因,我们认为,它是可能的,所观察到的X射线时间滞后可能携带的温暖的吸收体响应时间的签名,电离连续的变化。这些结果突出了了解暖吸收体对活动星系核X射线时间滞后的贡献的重要性,因为它也是解释与内发射区的传播和混响效应相关的滞后的重要信息。

英文摘要:

We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ~ 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051, whose spectrum has revealed a complex multicomponent wind. Making use of both RGS and EPIC-pn data, we performed a detailed analysis through a time-dependent photoionization code in combination with spectral and Fourier spectral-timing techniques. The source light curves and the warm absorber parameters obtained from the data were used to simulate the response of the gas due to variations in the ionizing flux of the central source. The resulting time variable spectra were employed to predict the effects of the warm absorber on the time lags and coherence of the energy dependent light curves. We have found that, in the absence of any other lag mechanisms, a warm absorber with the characteristics of the one observed in NGC 4051, is able to produce soft lags, up to 100 s, on timescales of ~ hours. The time delay is associated with the response of the gas to changes in the ionizing source, either by photoionization or radiative recombination, which is dependent on its density. The range of radial distances that, under our assumptions, yield longer time delays are comparable to the existing estimates of the location of the warm absorber in NGC 4051. For this reason, we suggest that it is likely that the observed X-ray time lags may carry a signature of the warm absorber response time, to changes in the ionizing continuum. These results highlight the importance of understanding the contribution of the warm absorber to the AGN X-ray time lags, since it is also vital information for interpreting the lags associated with propagation and reverberation effects in the inner emitting regions.

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