TNG-Cluster 中最亮团星系的恒星形成历史与熄灭
The star-forming past and quenching of brightest cluster galaxies in TNG-Cluster
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中文总结 AI 辅助
利用TNG-Cluster模拟，研究发现最亮团星系具有复杂恒星形成历史，经历多次重新活跃，最终因超大质量黑洞反馈导致的动能注入和气体排出而熄灭。
中文摘要 AI 辅助
在我们宇宙中最庞大星系团中的最亮团星系（BCGs）目前大多处于静止状态，呈椭圆形且颜色偏红。然而，它们的形成历史尚不明确，且很可能与低质量暗晕中的大质量椭圆星系不同。模拟面临同时需要大体积以采样大质量星系团和足够分辨率以模拟其恒星群体的挑战。因此，我们利用 TNG-Cluster——分辨率最高的星系团宇宙学模拟之一，该模拟在 $z=0$ 时提供了 352 个 BCG，其恒星质量 $M_{*, <30 \mathrm{pkpc}} = 10^{11.6-12.9} ~\mathrm{M}_\odot$，总暗晕质量 $M_{\mathrm{200c}} = 10^{14.3-15.4}~\mathrm{M}_\odot$。93% 的 BCG 在 $z=0$ 时已熄灭，而在红移 $z>3$ 时，它们的所有主要前体仍在形成恒星。单个 BCG 的恒星形成历史复杂，包括多次（重新）熄灭事件。自 $z=3$ 以来，它们平均重新活跃 $2.1 \pm 1.8$ 次。BCG 首次熄灭发生在 $9.9^{+0.9}_{-1.4} ~\mathrm{Gyr}$ 前（第 10 至第 90 百分位；$z=1.7^{+0.5}_{-0.5}$），而最后一次最终熄灭事件发生在 $7.0^{+2.8}_{-5.0} ~\mathrm{Gyr}$ 前（$z=0.8^{+0.8}_{-0.6}$）。我们发现首次和最后一次熄灭时的暗晕、恒星和超大质量黑洞（SMBH）质量存在很大离散，表明不存在发生熄灭的特征质量。相反，BCG 首次熄灭发生在它们的 SMBH 注入的累积动能等于 BCG 的结合能时，对应于首次 SMBH 动能注入后延迟 $2.3^{+1.2}_{-1.2} ~ \mathrm{Gyr}$。即，TNG-Cluster 的 BCG 在经历显著气体排出时熄灭。我们的工作表明，BCG 具有复杂多样的恒星形成历史，包含多次重新活跃事件，但最终因 SMBH 反馈而熄灭。
英文摘要
The Brightest Cluster Galaxies (BCGs) in the most massive galaxy clusters of our Universe are, at present, mostly quiescent, elliptical, and red. However, their formation histories are unclear and likely different from those of massive ellipticals in lower-mass haloes. Simulations face the challenge of simultaneously requiring large volumes to sample massive clusters and sufficient resolution to model their stellar populations. Therefore, we make use of TNG-Cluster, one of the highest-resolution cosmological simulations of galaxy clusters, which returns 352 BCGs at $z=0$ with stellar masses $M_{*, <30 \mathrm{pkpc}} = 10^{11.6-12.9} ~\mathrm{M}_\odot$ and total halo masses $M_{\mathrm{200c}} = 10^{14.3-15.4}~\mathrm{M}_\odot$. 93 per cent of the BCGs are quenched at $z=0$, whereas at redshift $z>3$ all their main progenitors were still star forming. The star-formation histories of individual BCGs are complex, including multiple (re)quenching episodes. They rejuvenate on average $2.1 \pm 1.8$ times since $z=3$. BCGs quench for the first time $9.9^{+0.9}_{-1.4} ~\mathrm{Gyr}$ ago (10th-90th percentiles; $z=1.7^{+0.5}_{-0.5}$), while the last and final quenching event occurred $7.0^{+2.8}_{-5.0} ~\mathrm{Gyr}$ ago ($z=0.8^{+0.8}_{-0.6}$). We find a large scatter in the halo, stellar, and SMBH masses at both first and last quenching, suggesting no characteristic mass at which quenching occurs. Instead, BCGs quench for the first time when the cumulative kinetic energy injected by their SMBH equals the BCG binding energy, corresponding to a delay of $2.3^{+1.2}_{-1.2} ~ \mathrm{Gyr}$ after the first SMBH kinetic energy injection. Namely, TNG-Cluster BCGs quench when they experience significant gas expulsion. Our work shows that BCGs have complex and varied star-formation histories, with multiple rejuvenation episodes, but they ultimately quench due to SMBH feedback.
发表机构
- Universität Heidelberg（海德堡大学）
- Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）
机构由 AI 辅助整理，请以论文原文为准。
