Compton thick absorber in type 1 quasar 3C 345 revealed by Suzaku and Swift/BAT
Compton thick absorber in type 1 quasar 3C 345 revealed by Suzaku and Swift/BAT
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DOI：
10.1093/mnras/stx754
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发表时间：
2017-03
影响因子：
4.8
通讯作者：
S. Eguchi
中科院分区：
文献类型：
--
作者：
S. Eguchi
分析了使用 Suzaku 和 Swift/BAT 获得的 $z = 0.5928$ 处的 1 型类星体 3C 345 的档案数据。尽管之前对该来源的研究仅应用了简单的破坏幂律模型，但考虑到 Akaike 信息标准，发现需要严重模糊的材料。 Murphy＆Yaqoob（2009）对数值环面模型的应用令人惊讶地揭示了康普顿厚2型核的存在，环面的视距氢柱密度为$N_{\rm H} = 10^{24.5}$ cm$^{-2}$，倾角为$\theta_{\rm inc} = 90^{\circ}$。然而，该模型未能考虑 Gu 等人通过光学观察获得的爱丁顿比。 （2001）和沉等人。 (2011)，或者要求存在超大质量黑洞双星，这是 Lobanov & Roland (2005) 提出的，因此该模型可能不适合 3C 345。还应用了部分覆盖电离吸收体模型，该模型解释了“硬过剩”1 型 AGN 中的吸收，并发现柱密度为 $N_{\rm H} \simeq 10^{25}$ 的康普顿厚吸收体cm$^{-2}$，电离参数$\log \xi \gtrsim 2$，覆盖率$75\% \lesssim f_{c} \lesssim 85\%$。由于该模型得到的黑洞质量为$\log ( M_{\rm BH} / M_{\odot} ) = 9.8$，这与Gu等人的光学观测结果一致。 (2001)，该模型可能是该源的最佳拟合模型。结果表明，3C 345 是此时距离最远、最隐蔽的硬多余活动星系核。
The archival data of 3C 345, a type 1 quasar at $z = 0.5928$, obtained with Suzaku and Swift/BAT are analysed. Though previous studies of this source applied only a simple broken power law model, a heavily obscuring material is found to be required by considering Akaike information criteria. The application of the numerical torus model by Murphy & Yaqoob (2009) surprisingly reveals the existence of Compton thick type 2 nucleus with the line-of-sight hydrogen column density of the torus of $N_{\rm H} = 10^{24.5}$ cm$^{-2}$ and the inclination angle of $\theta_{\rm inc} = 90^{\circ}$. However, this model fails to account for the Eddington ratio obtained with the optical observations by Gu et al. (2001) and Shen et al. (2011), or requires the existence of a supermassive black hole binary, which was suggested by Lobanov & Roland (2005), thus this model is likely to be inappropriate for 3C 345. A partial covering ionized absorber model which accounts for absorption in "hard excess" type 1 AGNs is also applied, and finds a Compton thick absorber with the column density of $N_{\rm H} \simeq 10^{25}$ cm$^{-2}$, the ionization parameter of $\log \xi \gtrsim 2$, and the covering fraction of $75\% \lesssim f_{c} \lesssim 85\%$. Since this model obtains a black hole mass of $\log ( M_{\rm BH} / M_{\odot} ) = 9.8$, which is consistent with the optical observation by Gu et al. (2001), this model is likely to be the best-fitting model of this source. The results suggest that 3C 345 is the most distant and most obscured hard excess AGN at this time.