论文标题
在宽带X射线光谱中揭示的“非合并”发光红外星系UGC 2608和NGC 5135中的Compton-Thick活性银河核的性质
Nature of Compton-thick Active Galactic Nuclei in "Non-merging'' Luminous Infrared Galaxies UGC 2608 and NGC 5135 Revealed with Broadband X-ray Spectroscopy
论文作者
论文摘要
我们利用Nustar，Suzaku，XMM-Newton和Chandra分析了两个“非合并”发光的红外星系（LIRGS）UGC 2608和NGC 5135中的活性银河核（AGN）的宽带X射线光谱。应用X射线块状模型（XClumpy：Tanimoto等人，2019年），我们发现这两个来源的光谱都具有相似的光谱（CT）吸收（$ n _ {\ rm H} $ <$ 20 $^{\ circ} $）。固有的2-10 KEV发光性为$ 3.9^{+2.2} _ { - 1.7} $ $ \ times $ $ $ $ 10^{43} $ erg s $^{ - 1} $（UGC 2608）和$ 2.0^{+3.3} （NGC 5135）。 [O IV]至核12 $μ$ m M的光度比大于典型的seyferts，这与从X型雷谱通过X型光谱的圆环宽度和圆柱密度估计的圆环覆盖因子（$ c _ {\ rm t} \ Lessim $ 0.7）一致。圆环覆盖因子和爱丁顿的比率（$λ_ {\ rm edd} \ sim $ 0.1）遵循Ricci等人发现的关系。 （2017c）对于局部AGN，这意味着由于AGN的明显辐射压力吹出了摩tori的某些部分，因此它们的摩ri变细。这些结果表明，这些“非合并” LIRG中的CT AGN只是通过较大的视线柱密度看到的正常AGN种群。它们与后期合并中埋藏的CT AGN相反，后期合并，即使在较大的爱丁顿比率下，也具有较大的圆环因素。
We have analyzed the broadband X-ray spectra of active galactic nuclei (AGNs) in two "non-merging" luminous infrared galaxies (LIRGs) UGC 2608 and NGC 5135, utilizing the data of NuSTAR, Suzaku, XMM-Newton, and Chandra. Applying the X-ray clumpy-torus model (XCLUMPY: Tanimoto et al. 2019), we find that both sources have similar spectra characterized by Compton-thick (CT) absorption ($N_{\rm H} \sim$ 5-7 $\times$ $10^{24}$ cm$^{-2}$) and small torus angular width ($σ$ $<$ 20$^{\circ}$). The intrinsic 2-10 keV luminosities are $3.9^{+2.2}_{-1.7}$ $\times$ $10^{43}$ erg s$^{-1}$ (UGC 2608) and $2.0^{+3.3}_{-1.0}$ $\times$ $10^{43}$ erg s$^{-1}$ (NGC 5135). The [O IV]-to-nuclear-12 $μ$m luminosity ratios are larger than those of typical Seyferts, which are consistent with the torus covering factors ($C_{\rm T} \lesssim$ 0.7) estimated from the torus angular widths and column densities by X-ray spectroscopy. The torus covering factors and Eddington ratios ($λ_{\rm Edd} \sim$ 0.1) follow the relation found by Ricci et al. (2017c) for local AGNs, implying that their tori become geometrically thin due to significant radiation pressure of the AGN that blows out some part of the tori. These results indicate that the CT AGNs in these "non-merger" LIRGs are just a normal AGN population seen edge-on through a large line-of-sight column density. They are in contrast to the buried CT AGNs in late-stage mergers that have large torus covering factors even at large Eddington ratios.
