arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1012.3345astro-ph.HE
收藏

12微米选定星系的XMM-牛顿光谱巡天。I. X射线数据

An XMM-Newton spectral survey of 12 micron selected galaxies. I. X-ray data

Murray Brightman, Kirpal Nandra

摘要:

我们对12微米星系样品中的126个星系进行了X射线光谱分析。我们特别注意康普顿厚AGN的帮助下,我们已经产生了新的光谱拟合模型,这是基于蒙特卡罗模拟的X射线辐射转移,使用球形和环面几何形状,并考虑到康普顿散射和Fe荧光。我们使用这些数据表明,在环面几何结构下,未被遮挡的视线可以达到约150 eV的Fe Kα线的最大EW,最初由Ghisellini,Haardt和Matt(1994)提出。为了超过这个值,必须用N_H>10^23 cm^-2来遮挡视线,正如我们在NGC 3690中所展示的那样。我们还从模拟数据中计算了通量抑制因子,由此得出的主要结论是,对于N_H> 10 ^25 cm^-2,在所有X射线波段和所有红移处,X射线通量都被抑制了10倍以上,这揭示了所有X射线巡天中固有的对这些极其严重遮蔽的系统的偏见。此外,我们确认了Murphy & Yaqoob(2009)的先前结果,该结果表明,相对于环形几何形状,由平板几何形状确定的反射分数被低估了。对于12微米选定的星系,我们研究了X射线幂律指数的分布,发现平均$<Γ>=1.90_{-0.07}^{+0.05}$和$σ_Γ= 0.31_{-0.05}^{+0.05}$的分布与以前的工作是一致的,并且对于遮蔽源和未遮蔽源的Γ分布与源的总体是一致的,在总体上支持统一方案。我们测定了样品中X射线活动星系核的康普顿厚度分数为18 ± 5%,这比硬X射线(>10 keV)样品的康普顿厚度分数高。最后我们发现,我们的样品的遮蔽率是X射线光度的强函数,在L_X~ 10 ^42 -43尔格·秒^-1处达到峰值。

英文摘要:

We present an X-ray spectral analysis of 126 galaxies of the 12 micron galaxy sample. We pay particular attention to Compton thick AGN with the help of new spectral fitting models that we have produced, which are based on Monte-Carlo simulations of X-ray radiative transfer, using both a spherical and torus geometry, and taking into account Compton scattering and Fe fluorescence. We use this data to show that with a torus geometry, unobscured sight lines can achieve a maximum EW of the Fe Kαline of ~150 eV, originally shown by Ghisellini, Haardt & Matt (1994). In order for this to be exceeded, the line of sight must be obscured with N_H>10^23 cm^-2, as we show for one case, NGC 3690. We also calculate flux suppression factors from the simulated data, the main conclusion from which is that for N_H>10^25 cm^-2, the X-ray flux is suppressed by a factor of >10 in all X-ray bands and at all redshifts, revealing the biases present against these extremely heavily obscured systems inherent in all X-ray surveys. Furthermore, we confirm previous results from Murphy & Yaqoob (2009) that show that the reflection fraction determined from slab geometries is underestimated with respect to toroidal geometries. For the 12 micron selected galaxies, we investigate the distribution of X-ray power-law indices, finding that the mean $<Γ>=1.90_{-0.07}^{+0.05}$ and $σ_Γ= 0.31_{-0.05}^{+0.05}$) is consistent with previous works, and that the distribution of Γfor obscured and unobscured sources is consistent with the source populations being the same, in general support of unification schemes. We determine a Compton thick fraction for the X-ray AGN in our sample to be 18+/-5% which is higher than the hard X-ray (>10 keV) selected samples. Finally we find that the obscured fraction for our sample is a strong function of X-ray luminosity, peaking at L_X~10^42-43 ergs s^-1.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑