The Apparent Host Galaxy of PKS 1413+135: HST, ASCA and VLBA Observations
The Apparent Host Galaxy of PKS 1413+135: HST, ASCA and VLBA Observations
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PKS 1413 135 的视主星系：HST、ASCA 和 VLBA 观测
DOI：
10.1086/344109
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
J. Conway
中科院分区：
文献类型：
--
作者：
E. Perlman;J. Stocke;C. Carilli;M. Sugiho;M. Tashiro;G. Madejski;Q. Wang;J. Conway
PKS 1413+135（z=0.24671）是少数几个有明显的旋涡星系的射电强活动星系核之一。以前的作者将其近指数红外截止归因于严重的吸收，但无法对吸收体或其在光学星系中的位置进行严格限制。此外，由于观测到的再发射辐射的缺乏，活动星系核与光学星系的关系仍然存在疑问。我们提出了新的HST，ASCA和VLBA的意见，抛出这些问题的重要新的光。HST观测揭示了PKS 1413+135的活性核的一种非常红色（V-H = 6.9等），这需要同步加速器老化和GMC大小的吸收体在几微米处的光谱转换。我们导出了一个内禀柱N_H = 4.6^{+2.1}_{-1.6} × 10^{22}cm^{-2}，覆盖分数f = 0.12^{+0.07}_{-0.05}。由于GMC很可能位于光学星系的盘中，因此我们的视线是相当不可能的（P ~ 2乘以10^{-4}）。GMC的特性是我们银河系中GMC的典型特征。HI吸收体的中心似乎距离原子核25毫角秒，而X射线和几乎所有的分子吸收体必须覆盖原子核，这意味着一个复杂的几何形状和云结构，分子核心沿着我们的视线到原子核。有趣的是，HST/NICMOS的数据要求活动星系核相对于光学星系偏心13 +/- 4毫角秒。这可以被解释为活动星系核的位置与光学星系相比在背景中很远，但它也可以用遮蔽和/或核结构来解释，这与观察到的缺乏多个图像更一致。
PKS 1413+135 (z=0.24671) is one of very few radio-loud AGN with an apparent spiral host galaxy. Previous authors have attributed its nearly exponential infrared cutoff to heavy absorption but have been unable to place tight limits on the absorber or its location in the optical galaxy. In addition, doubts remain about the relationship of the AGN to the optical galaxy given the observed lack of re-emitted radiation. We present new HST, ASCA and VLBA observations which throw significant new light on these issues. The HST observations reveal an extrremely red color (V-H = 6.9 mag) for the active nucleus of PKS 1413+135, requiring both a spectral turnover at a few microns due to synchrotron aging and a GMC-sized absorber. We derive an intrinsic column N_H = 4.6^{+2.1}_{-1.6} times 10^{22}cm^{-2} and covering fraction f = 0.12^{+0.07}_{-0.05}. As the GMC is likely in the disk of the optical galaxy, our sightline is rather unlikely (P ~ 2 times 10^{-4}). The properties of the GMC typical of GMCs in our own galaxy. The HI absorber appears centered 25 milliarcseconds away from the nucleus, while the X-ray and nearly all of the molecular absorbers must cover the nucleus, implying a complicated geometry and cloud structure, with a molecular core along our line of sight to the nucleus. Interestingly, the HST/NICMOS data require the AGN to be decentered relative to the optical galaxy by 13 +/- 4 milliarcseconds. This could be interpreted as suggestive of an AGN location far in the background compared to the optical galaxy, but it can also be explained by obscuration and/or nuclear structure, which is more consistent with the observed lack of multiple images.