活动星系核在Sunyaev-Zel'dovich选团簇中最亮星系中的中等红移活动
Active galactic nucleus activity in brightest cluster galaxies at intermediate redshifts in Sunyaev-Zel'dovich--selected clusters
- South African Astronomical Observatory（南非天文台）
- Department of Astronomy, University of Cape Town（开普敦大学天文学系）
- Wits Centre for Astrophysics, School of Physics, University of the Witwatersrand（威特沃特斯兰德大学物理学院天体物理中心）
- School of Mathematics, Statistics & Computer Science, University of KwaZulu-Natal（夸祖鲁-纳塔尔大学数学、统计与计算机科学学院）
- Centre for Space Research, North-West University（西北大学空间研究中心）
- National Institute for Theoretical and Computational Sciences (NITheCS)（国家理论与计算科学研究所）
- Inter-University Centre for Astronomy and Astrophysics（大学间天文学与天体物理学中心）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过分析171个SZ选团簇中的BCG，发现其中22%的射电噪AGN主要为低激发、辐射低效系统，吸积效率随红移增加，表明维持模式吸积在中等红移大质量团中普遍存在。
AI中文摘要：
背景。最亮团星系（BCGs）承载着强大的活动星系核（AGNs），并有助于调节团内介质的加热-冷却平衡。虽然射电模式反馈在本地已得到充分证实，但其在中等红移处的普遍性仍缺乏约束。目的。我们研究了在$0.3 < z < 0.8$的Sunyaev-Zel'dovich（SZ）选团簇中BCG内AGN的发生率、吸积状态和宿主星系性质，检验其与宇宙纪元、团质量和动力学状态的依赖性。方法。我们分析了来自阿塔卡马宇宙学望远镜SZ星表的171个BCG，结合南非大型望远镜光谱、WISE中红外测光和快速ASKAP连续巡天的射电数据，并使用X-CIGALE建模来推导恒星质量、恒星形成率和爱丁顿标度吸积率。结果。三十八个BCG（22%）拥有射电噪AGN。其中只有两个（约5%）是高激发射电星系；其余为低激发系统。大多数AGN具有低的爱丁顿比率（$-3 \lesssim \log_{10}\lambda_{\mathrm{Edd}} \lesssim -1$），与辐射低效吸积一致。吸积效率随红移增加，而与团质量和动力学状态的相关性较弱。射电光度与团质量无关。与场射电AGN相比，BCG射电噪AGN具有相似的射电功率，但宿主星系质量大约高0.8个数量级。结论。在$0.3 < z < 0.8$处，BCG射电噪AGN主要是低激发、辐射低效的系统，表明在大质量团（$M_{500c} \simeq 3.2 \times 10^{14},M_\odot$）中，维持模式吸积在$z \sim 1$时已广泛存在。吸积似乎主要由燃料可用性和宇宙演化而非整体团性质调节，而团环境主要设定宿主星系的质量尺度。
英文摘要：
Context. Brightest cluster galaxies (BCGs) host powerful active galactic nuclei (AGNs) and help regulate the heating--cooling balance of the intracluster medium. While radio-mode feedback is well established locally, its prevalence at intermediate redshifts remains poorly constrained. Aims. We investigate the incidence, accretion state, and host-galaxy properties of AGNs in BCGs in Sunyaev--Zel'dovich (SZ)-selected clusters at $0.3 < z < 0.8$, testing dependences on cosmic epoch, cluster mass, and dynamical state. Methods. We analyse 171 BCGs from the Atacama Cosmology Telescope SZ catalogue, combining Southern African Large Telescope spectroscopy, WISE mid-infrared photometry, and Rapid ASKAP Continuum Survey radio data with X-CIGALE modelling to derive stellar masses, star formation rates, and Eddington-scaled accretion rates. Results. Thirty-eight BCGs (22%) host radio-loud AGNs. Only two ($\sim$5%) are high-excitation radio galaxies; the remainder are low-excitation systems. Most AGNs have low Eddington ratios ($-3 \lesssim \log_{10}λ_{\mathrm{Edd}} \lesssim -1$), consistent with radiatively inefficient accretion. Accretion efficiency increases with redshift, while correlations with cluster mass and dynamical state are weak. Radio luminosity is independent of cluster mass. Compared to field radio AGNs, BCG radio-loud AGNs have similar radio powers but are hosted by galaxies $\sim0.8$ dex more massive. Conclusions. BCG radio-loud AGNs at $0.3 < z < 0.8$ are predominantly low-excitation, radiatively inefficient systems, indicating that maintenance-mode accretion was widespread in massive clusters ($M_{500c} \simeq 3.2 \times 10^{14},M_\odot$) by $z \sim 1$. Accretion appears regulated primarily by fuel availability and cosmic evolution rather than global cluster properties, while the cluster environment mainly sets the host-galaxy mass scale.
