On why the iron K-shell absorption in AGN is not a signature of the local warm/hot intergalactic medium
On why the iron K-shell absorption in AGN is not a signature of the local warm/hot intergalactic medium
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DOI：
10.1111/j.1745-3933.2008.00443.x
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发表时间：
2008-01
影响因子：
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通讯作者：
J. Reeves;C. Done;K. Pounds;Y. Terashima;K. Hayashida;N. Anabuki
中科院分区：
文献类型：
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作者：
J. Reeves;C. Done;K. Pounds;Y. Terashima;K. Hayashida;N. Anabuki
我们比较了2001年XMM-牛顿和2005年朱雀观测的类星体PG 1211+143，z= 0.0809。在7千电子伏的铁K壳层吸收线（在类星体框架中为7.6千电子伏）中观察到可变性，这在2005年比2001年XMM-牛顿观测期间明显减弱。从4 × 103 cm−3的复合时标，而吸收柱是5 × 1022 < NH < 1 × 1024 cm−2。因此，吸收体的尺寸尺度太紧凑（pc尺度），稠密气体的表面亮度太高（9-10个数量级），不可能是由局部热气体引起的，例如局部气泡，群或温暖/热的星系际介质（WHIM），正如McKernan，Yaqoob和Reynolds所建议的那样。相反，铁K壳层吸收必须与活动星系核（AGN）流出温和的相对论速度。最后，我们表明，在PG 1211+143的吸收与当地的热气体的关联只是一个巧合，和其他活动星系核的衰退和铁K吸收外流速度之间的比较没有揭示一对一的运动学相关性。
We present a comparison between the 2001 XMM–Newton and 2005 Suzaku observations of the quasar, PG 1211+143, at z= 0.0809. Variability is observed in the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which is significantly weaker in 2005 than during the 2001 XMM–Newton observation. From a recombination time-scale of 4 × 103 cm−3, while the absorber column is 5 × 1022 < NH < 1 × 1024 cm−2. Thus, the size scale of the absorber is too compact (pc scale) and the surface brightness of the dense gas too high (by 9–10 orders of magnitude) to arise from local hot gas, such as the local bubble, group or warm/hot intergalactic medium (WHIM), as suggested by McKernan, Yaqoob & Reynolds. Instead, the iron K-shell absorption must be associated with an active galactic nucleus (AGN) outflow with mildly relativistic velocities. Finally, we show that the association of the absorption in PG 1211+143 with local hot gas is simply a coincidence, and the comparison between the recession and iron K absorber outflow velocities in other AGN does not reveal a one-to-one kinematic correlation.