Testing the Radio-selection Method of Dual Active Galactic Nuclei in the Stripe 82 Field
Testing the Radio-selection Method of Dual Active Galactic Nuclei in the Stripe 82 Field
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DOI：
10.3847/1538-4357/acb646
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发表时间：
2022-12
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影响因子：
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通讯作者：
Arran C. Gross;Hai-jiang Fu;A. Myers;S. Djorgovski;Joshua L. Steffen;J. Wrobel
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作者：
Arran C. Gross;Hai-jiang Fu;A. Myers;S. Djorgovski;Joshua L. Steffen;J. Wrobel
我们测试合并引起的双活动星系核（dAGN）的范例使用的样本35个射电星系对从斯隆数字巡天条纹82字段。使用凯克光谱，我们确认21对具有一致的红移，构成运动学对，其余14对是视线投影。我们通过发射线比，等效宽度，以及超过星星形成预测输出的无线电功率的光学光谱特征进行分类。我们发现六个星系被归类为LINER和七个AGN/星暴复合。大部分LINER是退休星系，而复合星系可能有活动星系核的贡献。所有的运动学对都表现出比预期的星星形成水平高出10倍以上的射电功率，暗示了射电活动星系核的贡献。我们还分析了高分辨率（0.″3）成像在6 GHz的NSF的卡尔G。Jansky甚大阵列的17个运动学对。我们发现六对（两个新的，四个以前已知的）主机两个独立的无线电核心，确认其作为dAGN的地位。剩下的11对包含单个活动星系核，其中大多数显示出突出的喷流/叶重叠其同伴。我们的最终普查表明，dAGN的占空比略高于纯粹随机加油的预测，尽管需要更大的样本（可能从VLASS中挑选）来完全解决dAGN部分。我们的结论是，虽然dAGN在条纹82领域是罕见的，合并过程中发挥了一定的作用，在他们的触发，它有利于低到中等水平的吸积。
We test the merger-induced dual active galactic nuclei (dAGNs) paradigm using a sample of 35 radio galaxy pairs from the Sloan Digital Sky Survey Stripe 82 field. Using Keck optical spectroscopy, we confirm 21 pairs have consistent redshifts, constituting kinematic pairs; the remaining 14 pairs are line-of-sight projections. We classify the optical spectral signatures via emission line ratios, equivalent widths, and excess of radio power above star formation predicted outputs. We find six galaxies are classified as LINERs and seven are AGN/starburst composites. Most of the LINERs are retired galaxies, while the composites likely have AGN contribution. All of the kinematic pairs exhibit radio power more than 10× above the level expected from just star formation, suggestive of a radio AGN contribution. We also analyze high-resolution (0.″3) imaging at 6 GHz from the NSF’s Karl G. Jansky Very Large Array for 17 of the kinematic pairs. We find six pairs (two new, four previously known) host two separate radio cores, confirming their status as dAGNs. The remaining 11 pairs contain single AGNs, with most exhibiting prominent jets/lobes overlapping their companion. Our final census indicates a dAGN duty cycle slightly higher than predictions of purely stochastic fueling, although a larger sample (potentially culled from VLASS) is needed to fully address the dAGN fraction. We conclude that while dAGNs in the Stripe 82 field are rare, the merger process plays some role in their triggering and it facilitates low to moderate levels of accretion.