The relationship between the incidence of X-ray selected AGN in nearby galaxies & star-formation rate
The relationship between the incidence of X-ray selected AGN in nearby galaxies & star-formation rate
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DOI：
10.1093/mnras/stad1723
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发表时间：
2023-06
影响因子：
4.8
通讯作者：
K. Birchall;M. Watson;J. Aird;R. Starling
中科院分区：
文献类型：
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作者：
K. Birchall;M. Watson;J. Aird;R. Starling
我们提出的识别和分析的X射线选择AGN样本，位于本地（z < 0.35）星系人口。从22079个MPA-JHU（基于SDSS DR 8）星系的母样本中，我们确定了917个星系的中心，多余的X射线发射（来自3XMM-DR 7）可能来自AGN。我们测量了宿主星系的星星形成率，并根据它们相对于星星形成主序列的位置将它们分为恒星形成和静止。只有72%的X射线选定的样品被确定为活动星系核使用BPT选择;这种技术是在静止主机有效得多，只有确定50%的X射线活动星系核。我们还计算了这些活动星系核的黑洞的增长率，根据它们的比吸积率（MLX/M*），发现静止星系的平均吸积率低于恒星形成星系。最后，我们测量了3XMM的灵敏度函数，这样我们就可以校正观测偏差，并构建概率分布作为吸积率的函数。活动星系核在恒星形成和静止星系的星星形成速率（$log _{10} \，\mathrm{SFR/M_\odot \ yr^{-1}} = -3\mathrm{to}\ 2$）范围内都有发现。与具有相同恒星质量和红移的静止星系相比，在恒星形成星系中活动星系核的发生率增加了2倍（3.5σ显著性），但我们也发现静止星系中有大量活动星系核。
We present the identification and analysis of an X-ray selected AGN sample that lie within the local (z < 0.35) galaxy population. From a parent sample of 22 079 MPA-JHU (based on SDSS DR8) galaxies, we identified 917 galaxies with central, excess X-ray emission (from 3XMM-DR7) likely originating from an AGN. We measured the host galaxies’ star formation rates and classified them as either star-forming or quiescent based on their position relative to main sequence of star formation. Only 72 per cent of the X-ray selected sample were identified as AGN using BPT selection; this technique is much less effective in quiescent hosts, only identifying 50 per cent of the X-ray AGN. We also calculated the growth rates of the black holes powering these AGN in terms of their specific accretion rate (∝ LX/M*) and found quiescent galaxies, on average, accrete at a lower rate than star-forming galaxies. Finally, we measured the sensitivity function of 3XMM so we could correct for observational bias and construct probability distributions as a function of accretion rate. AGN were found in galaxies across the full range of star formation rates ($\log _{10} \, \mathrm{SFR/M_\odot \ yr^{-1}} = -3\ \mathrm{to}\ 2$) in both star-forming and quiescent galaxies. The incidence of AGN was enhanced by a factor 2 (at a 3.5σ significance) in star-forming galaxies compared to quiescent galaxies of equivalent stellar mass and redshift, but we also found a significant population of AGN hosted by quiescent galaxies.