On the detectability of distant Compton-thick obscured quasars
On the detectability of distant Compton-thick obscured quasars
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关于遥远康普顿厚模糊类星体的可探测性
DOI：
10.1046/j.1365-8711.2002.05138.x
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发表时间：
2001
影响因子：
4.8
通讯作者：
C. Crawford
中科院分区：
文献类型：
--
作者：
A. Fabian;R. Wilman;C. Crawford
钱德拉和XMM-牛顿已经将2-8keV X射线背景(XRB)分解为点源。许多较暗的源是暗淡的活动星系核(AGN)，其柱密度在1022-1023厘米-2范围内，其中一些具有类星体的发光。根据遮蔽模型，8keV以上的XRB主要是来自康普顿厚的AGN的发射，柱密度超过1.5×10~(24)cm~(-2)。在这里，我们考虑了厚康普顿类星体是否可以被钱德拉和XMM-牛顿通过它们的直接(即非散射)X射线发射探测到。如果对象各自具有高光度和高红移，则探测能力被优化，从而使直接发射在观察到的波段中具有显著的通量。使用一个包含吸积黑洞的简单星系形成模型，在该模型中，类星体以康普顿厚度的方式建立其大部分质量，然后驱逐出遮蔽物质。我们预测，中等深度的100k钱德拉和XMM-牛顿曝光可能包含少数可检测到的康普顿厚度的类星体。深毫秒或更多的钱德拉图像应该包含50-100个遥远的、光学上微弱的、康普顿厚的震源。此外，我们还发现，辐射压力可以像类星体风一样有效地驱逐遮蔽气体，并产生与主体凸起的速度弥散成正比的黑洞质量的四次方。
Chandra and XMM-Newton have resolved the 2-8 keV X-ray background (XRB) into point sources. Many of the fainter sources are obscured active galactic nuclei (AGN) with column densities in the range of 10 2 2 - 10 2 3 cm - 2 , some of which have quasar-like luminosities. According to obscuration models, the XRB above 8 keV is dominated by emission from Compton-thick AGN, with column densities exceeding 1.5 X 10 2 4 cm - 2 . Here, we consider whether Compton-thick quasars are detectable by Chandra and XMM-Newton by their direct (i.e. not scattered) X-ray emission. Detectability is optimized if the objects individually have a high luminosity and high redshift, so that the direct emission has a significant flux in the observed band. Using a simple galaxy formation model incorporating accreting black holes, in which quasars build most of their mass in a Compton-thick manner before expelling the obscuring matter, we predict that moderately deep 100-ks Chandra and XMM-Newton exposures may contain a handful of detectable Compton-thick quasars. Deep Ms or more Chandra images should contain 50-100 distant, optically faint, Compton-thick sources. In passing we show that radiation pressure can be as effective in expelling the obscuring gas as quasars winds, and yields a black hole mass proportional to the velocity dispersion of the host bulge to the fourth power.