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arXiv 1209.0274astro-ph.GAastro-ph.COastro-ph.HE
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真2型塞弗特星系的同时X射线和光学观测

Simultaneous X-ray and optical observations of true Type 2 Seyfert galaxies

Stefano Bianchi, Francesca Panessa, Xavier Barcons, Francisco J. Carrera, Fabio La Franca, Giorgio Matt, Francesca Onori, Anna Wolter, Amalia Corral, Lorenzo Mo… 展开作者

Stefano Bianchi, Francesca Panessa, Xavier Barcons, Francisco J. Carrera, Fabio La Franca, Giorgio Matt, Francesca Onori, Anna Wolter, Amalia Corral, Lorenzo Monaco, Angel Ruiz, Murray Brightman

摘要:

我们提出了一个运动的结果,同时X射线和光学观测的“真正的”2型塞弗特星系候选人,即活动星系核没有一个宽线区(BLR)。在由8个源组成的初始样本中,一个对象IC 1631被发现是一个错误分类的星暴星系,另一个对象Q2130-431确实显示出宽的光学线,而另外两个对象IRAS 01428 -0404和NGC 4698很可能被沿着视线的康普顿厚度气体吸收。因此,这四个来源不是未吸收的塞弗特2如以前在文献中建议。另一方面,我们确认NGC 3147,NGC 3660和Q2131-427属于真正的2型塞弗特星系,因为它们没有表现出任何证据的广泛组成部分的光学线,也没有在其X射线光谱的遮蔽。这三个来源有低吸积率($\dot{m}= L_{bol}/L_{Edd} \la0.01$),与理论模型预测的BLR消失低于$L_{bol}/L_{Edd}$的临界值。最后一个源,Mrk 273 x,即使在这个依赖于吸积的统一模型版本中也是一个例外,因为它的X射线亮度和吸积率都很高,而且没有遮蔽的证据。然而,将其光学分类为塞弗特2只是基于缺乏Hβ的宽成分,因为缺乏包含Hα带的光谱。

英文摘要:

We present the results of a campaign of simultaneous X-ray and optical observations of `true' Type 2 Seyfert galaxies candidates, i.e. AGN without a Broad Line Region (BLR). Out of the initial sample composed by 8 sources, one object, IC1631, was found to be a misclassified starburst galaxy, another, Q2130-431, does show broad optical lines, while other two, IRAS01428-0404 and NGC4698, are very likely absorbed by Compton-thick gas along the line of sight. Therefore, these four sources are not unabsorbed Seyfert 2s as previously suggested in the literature. On the other hand, we confirm that NGC3147, NGC3660, and Q2131-427 belong to the class of true Type 2 Seyfert galaxies, since they do not show any evidence for a broad component of the optical lines nor for obscuration in their X-ray spectra. These three sources have low accretion rates ($\dot{m}= L_{bol}/L_{Edd} \la0.01$), in agreement with theoretical models which predict that the BLR disappears below a critical value of $L_{bol}/L_{Edd}$. The last source, Mrk273x, would represent an exception even of this accretion-dependent versions of the Unification Models, due to its high X-ray luminosity and accretion rate, and no evidence for obscuration. However, its optical classification as a Seyfert 2 is only based on the absence of a broad component of the Hβ, due to the lack of optical spectra encompassing the Hα band.

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。

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