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arXiv 1607.02635astro-ph.HE
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窄线Seyfert 1星系1H 0707 -495和IRAS 13224-3809中宽铁L线的存在性

On the reality of broad iron L lines from the narrow line Seyfert 1 galaxies 1H0707-495 and IRAS 13224-3809

Pramod Pawar, Gulab Dewangan, Madhav Patil, Ranjeev Misra, Sharada Jogadand

摘要:

我们使用长时间XMM-牛顿观测对1H 0707 -495和IRAS 13224-3809进行了时间分辨光谱分析。这些都是强变窄线塞弗特1星系,并显示广泛的功能约1千电子伏,已被解释为相对论广泛的铁L $α$线。这些特征在其他活动星系核中没有被清楚地观察到,尽管有时具有最佳拟合的模糊反射模型所要求的高铁丰度。鉴于这些线的重要性,我们探讨的可能性,如果快速变化的光谱参数可能会引入广泛的颠簸/骤降人工的时间平均光谱,这可能会被误认为是加宽线。我们通过使用长(> 100 ks)XMM-牛顿观测进行时间分辨光谱并将其划分为具有几ks典型曝光的段来测试该假设。我们从每个这样的片段提取光谱,并使用由幂律表示硬组分和黑体表示软发射组成的双组分唯象模型进行建模。正如预期的那样,这两个源显示出光谱参数的变化。利用这些变化趋势,我们模拟了每个片段的模型光谱,然后共同添加以获得组合的模拟光谱。在模拟的光谱中,我们发现没有广泛的功能低于1千电子伏,特别是没有偏差0.9千电子伏附近看到的真正的平均光谱。这意味着广泛的铁L?在这些源的光谱中看到的线不是光谱分量变化的伪像,因此提供了该线确实是真实的证据。

英文摘要:

We performed time resolved spectroscopy of 1H0707-495 and IRAS 13224-3809 using long XMM-Newton observations. These are strongly variable narrow line Seyfert 1 galaxies and show broad features around 1 keV that has been interpreted as relativistically broad Fe L$α$ lines. Such features are not clearly observed in other AGN despite sometimes having high iron abundance required by the best fitted blurred reflection models. Given the importance of these lines, we explore the possibility if rapid variability of spectral parameters may introduce broad bumps/dips artificially in the time averaged spectrum, which may then be mistaken as broadened lines. We tested this hypothesis by performing time resolved spectroscopy using long (> 100 ks) XMM-Newton observations and by dividing it into segments with typical exposure of few ks. We extracted spectra from each such segment and modelled using a two component phenomenological model consisting of a power law to represent hard component and a black body to represent the soft emission. As expected both the sources showed variations in the spectral parameters. Using these variation trends, we simulated model spectra for each segment and then co-added to get a combined simulated spectrum. In the simulated spectra, we found no broad features below 1 keV and in particular no deviation near 0.9 keV as seen in the real average spectra. This implies that the broad Fe L? line that is seen in the spectra of these sources is not an artifact of the variation of spectral components and hence providing evidence that the line is indeed genuine.

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