Properties of X-ray-selected broad absorption-line quasars ?
Properties of X-ray-selected broad absorption-line quasars ?
复制标题
X 射线选择的宽吸收线类星体的特性？
DOI：
10.1111/j.1365-2966.2008.13825.x
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发表时间：
2008
影响因子：
4.8
通讯作者：
Blustin A
中科院分区：
文献类型：
--
作者：
Blustin A
宽吸收线类星体(通常称为BALQSO)包含最引人注目的活动星系核(AGN)驱动风的例子。在这些风中的高吸收柱，∼1024厘米−2，确保了BALQSO通常是X射线微弱的。这种高X射线吸收意味着几乎所有的BALQSO都是通过光学测量发现的，所以我们对它们的X射线性质所知甚少来自于非常明亮的光学选择来源。然而，最近在深部X射线测量领域中发现了少量X射线选择的BALQSO(XBALQSO)。本文研究了五个XBALQSOs的X射线和静止标架紫外线(UV)性质，获得了XMM-NewtonEPIC X射线谱和深部光学成像和光谱。我们发现，尽管XBALQSO的αOXIS比正常类星体高∼0.5%，但它们的中值αOXIS却比可比的光学选择类星体(OBALQSO)平坦了0.30。我们排除了较高的X射线与光通量比是由于本征光学消光的可能性。我们发现，XBALQSOs中风对X射线和紫外线的吸收与OBALQSOs中相应的风吸收量相似，甚至可能大于OBALQSOs中相应的风吸收量，因此较平的α氧不可能是较弱的风吸收的结果。我们得出的结论是，这些XBALQSO比我们与之比较的OBALQSO样本具有更高的X射线与光通量比。
Broad absorption-line quasars (commonly termed BALQSOs) contain the most dramatic examples of active galactic nucleus (AGN) driven winds. The high absorbing columns in these winds, ∼1024cm−2, ensure that BALQSOs are generally X-ray faint. This high X-ray absorption means that almost all BALQSOs have been discovered through optical surveys, and so what little we know about their X-ray properties is derived from very bright optically selected sources. A small number of X-ray-selected BALQSOs (XBALQSOs) have, however, recently been found in deep X-ray survey fields. In this paper we investigate the X-ray and rest-frame ultraviolet (UV) properties of five XBALQSOs for which we have obtainedXMM–NewtonEPIC X-ray spectra and deep optical imaging and spectroscopy. We find that, although the XBALQSOs have an αoxsteeper by ∼0.5 than normal QSOs, their median αoxis nevertheless flatter by 0.30 than that of a comparable sample of optically selected BALQSOs (OBALQSOs). We rule out the possibility that the higher X-ray to optical flux ratio is due to intrinsic optical extinction. We find that the amount of X-ray and UV absorption due to the wind in XBALQSOs is similar, or perhaps greater than, the corresponding wind absorption in OBALQSOs, so the flatter αoxcannot be a result of weaker wind absorption. We conclude that these XBALQSOs have intrinsically higher X-ray to optical flux ratios than the OBALQSO sample with which we compare them.