论文标题
Chandra X射线对光学选择的AGN对调查
A Chandra X-ray Survey of Optically Selected AGN Pairs
论文作者
论文摘要
我们提出了Chandra档案研究，该研究是针对光学选择的AGN对，上间是红移$ \ bar {z} \ sim $ 0.1。 Out of 1286 AGN pairs (with projected separations $r_p < 100$ kpc and velocity offsets $Δv < 600$ km s$^{-1}$) optically identified from the Sloan Digital Sky Survey Seventh Data Release, we find 67 systems with archival Chandra observations, which represent the largest sample of optically selected AGN pairs studied in the X-ray.在67对AGN对中，在X射线中检测到21个核，36个在X射线中检测到一个核，而10个没有X射线检测。 X射线检测率为78/134 = 58％（$ \ pm 7 $％1 $σ$ poisson错误），明显高于（23/134 = $ 17 \％\％\％\％\％$ $）的恒星形成星系对的比较样本，对光学AGN分类的贷款支持。在去除X射线污染的保守情况下，X射线检测率变为$ 27 \％\ pm 4 \％$，与最新的Galaxy合并模拟的预测一致。 2-10 KEV X射线光度$ L_ {2-10〜 {\ rm KeV}} $增加，随着$ R_P \ GTRSIM 15 $ kpc的AGN对减少预计的分离，这表明即使在早期合并中也可以增强黑洞积聚。另一方面，$ l_ {2-10〜 {\ rm kev}} $似乎会随着$ r_p \ lyssim 15 $ kpc的减少而减小，这与合并模拟的预测相矛盾。 $ l_ {2-10〜 {\ rm kev}} $在$ r_p \ Lessim 15 $ kpc中的明显下降可能是：需要使用较大样本的未来X射线研究将我们的结果置于更牢固的统计基础上。
We present a Chandra archival study of optically selected AGN pairs at a median redshift $\bar{z} \sim$ 0.1. Out of 1286 AGN pairs (with projected separations $r_p < 100$ kpc and velocity offsets $Δv < 600$ km s$^{-1}$) optically identified from the Sloan Digital Sky Survey Seventh Data Release, we find 67 systems with archival Chandra observations, which represent the largest sample of optically selected AGN pairs studied in the X-ray. Among the 67 AGN pairs, 21 systems have both nuclei detected in the X-rays, 36 have one nucleus detected in the X-rays, whereas 10 have no X-ray detection. The X-ray detection rate, 78/134 = 58% ($\pm 7$% 1$σ$ Poisson errors), is significantly higher than that (23/134 = $17\% \pm 4\%$) of a comparison sample of star-forming galaxy pairs, lending support to the optical AGN classification. In the conservative case where X-ray contamination from star formation is removed, the X-ray detection rate becomes $27\% \pm 4\%$, consistent with predictions from latest galaxy merger simulations. The 2-10 keV X-ray luminosity $L_{2-10~{\rm keV}}$ increases with decreasing projected separation in AGN pairs for $r_p \gtrsim 15$ kpc, suggesting an enhancement of black hole accretion even in early-stage mergers. On the other hand, $L_{2-10~{\rm keV}}$ appears to decrease with decreasing projected separation at $r_p \lesssim 15$ kpc, which is contradictory to predictions from merger simulations. The apparent decrease in $L_{2-10~{\rm keV}}$ of AGN pairs at $r_p \lesssim 15$ kpc may be caused by: (i) enhanced absorbing columns from merger-induced gas inflows, (ii) feedback effects from early-stage mergers, and/or (iii) small number statistics. Future X-ray studies with larger samples are needed to put our results on firmer statistical ground.
