The incidence of X-ray selected AGN in nearby galaxies
The incidence of X-ray selected AGN in nearby galaxies
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附近星系中 X 射线选择 AGN 的发生率
DOI：
10.1093/mnras/stab3573
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发表时间：
2022
影响因子：
4.8
通讯作者：
Birchall K
中科院分区：
文献类型：
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作者：
Birchall K
我们对位于本地星系群内的活动星系核（AGN）的无偏样本进行了识别和分析。使用 MPA-JHU 目录（基于 SDSS DR8）和 3XMM DR7，我们定义了 25 949 个本地星系（z≤ 0.33）的母样本。在确认严格不存在 AGN 光污染恒星质量和恒星形成率计算后，我们确定了 917 个星系，其中心的过量 X 射线发射可能源自 AGN。我们使用 BPT 诊断分析了它们的光学发射线，并证实此类技术能够更有效地可靠地识别较高质量星系中的 AGN 源：从最低质量箱中的 30% 一致性上升到最高质量箱中的 93%。然后，我们根据特定吸积率 (∝LX/M*) 计算了为活动星系核提供动力的黑洞的增长率。我们的样本表现出广泛的吸积率，其中大多数以爱丁顿光度的速率吸积。最后，我们使用我们的样本来计算 AGN 的发生率作为恒星质量和红移的函数。在校正 3XMM 的不同灵敏度后，我们按恒星质量和红移分割星系样本，并研究 AGN 分数作为 X 射线光度和特定黑洞吸积率的函数。由此我们发现，在 8 < log M*/M⊙< 12 的恒星质量上，活动星系核在固定特定吸积率限制 10−3.5 之上的星系比例是恒定的 (at)，并随着红移而增加（从 10%）。
We present the identification and analysis of an unbiased sample of active galactic nuclei (AGN) that lie within the local galaxy population. Using the MPA-JHU catalogue (based on SDSS DR8) and 3XMM DR7 we define a parent sample of 25 949 local galaxies (z≤ 0.33). After confirming that there was strictly no AGN light contaminating stellar mass and star-formation rate calculations, we identified 917 galaxies with central, excess X-ray emission likely originating from an AGN. We analysed their optical emission lines using the BPT diagnostic and confirmed that such techniques are more effective at reliably identifying sources as AGN in higher mass galaxies: rising from 30 per cent agreement in the lowest mass bin to 93 per cent in the highest. We then calculated the growth rates of the black holes powering these AGN in terms of their specific accretion rates (∝LX/M*). Our sample exhibits a wide range of accretion rates, with the majority accreting at ratesof their Eddington luminosity. Finally, we used our sample to calculate the incidence of AGN as a function of stellar mass and redshift. After correcting for the varying sensitivity of 3XMM, we split the galaxy sample by stellar mass and redshift and investigated the AGN fraction as a function of X-ray luminosity and specific black hole accretion rate. From this we found the fraction of galaxies hosting AGN above a fixed specific accretion rate limit of 10−3.5is constant (at) over stellar masses of 8 < log M*/M⊙< 12 and increases (fromto 10 per cent) with redshift.