LINER的多面体性质：射电星系LINER的XMM-牛顿观点
The polyhedral nature of LINERs: An XMM-Newton view of LINERs in radio galaxies
摘要：
目的：本文研究了最近用XMM观测到的NGC 1692、PKS 0625 -35、3C 88、3C 444等4个射电星系LINER的X射线起源和吸积流的性质。研究方法：我们结合的时间平均光谱分析与模型无关的信息，从X射线的时间和光谱变异性分析，并与额外的宽带信息（紫外线和无线电）的结果。结果：我们的样本的爱丁顿比的值跨越2个数量级。4活动星系核充分拟合由相同的连续模型，包括至少一个热分量和部分吸收的功率定律，其相对贡献和光子指数变化很大，从源到源。NGC 1692和PKS 0625 -35具有相当陡峭的幂律分量，可能表明来自喷流的同步辐射。相反，针对3C 88导出的平坦光子指数可以指示严重吸收的对象。最后，3C 444的时间平均光谱特性（伽玛~1.9和一个明显的线状过剩约6.7 keV）更符合塞弗特星系。时间分析表明，PKS 0625 -35和3C 88在软能带中具有显著的变化。PKS 0625 -35还显示了月时间尺度上光谱变异性的提示性证据。来自宽带分析的主要发现可以总结如下：1）3C 444、PKS 0625 -35和NGC 1692具有与公知的α_OX -1_UV相关性一致的α_OX值。2)L_X与倾斜角之间无正相关关系，表明X射线发射不是束化的。3)无线电响度的值与爱丁顿比成反比，并且将我们的对象定位在R-l_UV平面中的“无线电静音”和“无线电静音”分支之间。
英文摘要：
Aims: We investigate the origin of X-rays and the nature of accretion flow in 4 LINERs hosted by radio galaxies, namely NGC1692, PKS0625-35, 3C88, 3C444, recently observed with XMM. Methods: We combine the results from the time-averaged spectral analysis with model-independent information from X-ray temporal and spectral variability analyses, and with additional broadband information (UV and radio). Results: The values of the Eddington ratios of our sample span 2 orders of magnitude. The 4 AGN are adequately fitted by the same continuum model that comprises at least one thermal component and a partially absorbed power law, whose relative contribution and photon index vary substantially from source to source. NGC1692 and PKS0625-35 have fairly steep power-law components, perhaps indicative of synchrotron emission from a jet. Conversely, the flat photon index derived for 3C88 may be indicative of a heavily absorbed object. Finally, the time-averaged spectral properties of 3C444 (Gamma~1.9 and an apparent line-like excess around 6.7 keV) are more in line with Seyfert galaxies. The temporal analysis reveals that PKS0625-35 and 3C88 are significantly variable in the soft energy band. PKS0625-35 also shows suggestive evidence of spectral variability on timescales of months. The main findings from the broadband analysis can be summarized as follows: 1) 3C444, PKS0625-35, and NGC1692 have alpha_OX values consistent with the well known alpha_OX -l_UV correlation. 2) No positive correlation is found between L_X and the inclination angle, suggesting that the X-ray emission is not beamed. 3) The values of the radio-loudness are inversely proportional to the Eddington ratio and locate our objects in between the ``radio-loud'' and ``radio-quiet'' branches in the R- l_UV plane.
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