发表机构
University of Florida; University of Virginia; Virginia Institute for Theoretical Astronomy（佛罗里达大学; 弗吉尼亚大学; 弗吉尼亚理论天文学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用IllustrisTNG-50和BRAHMA模拟，发现星系并合在低红移显著增强恒星形成和黑洞吸积，但在高红移及不同种子模型下增强减弱，揭示了并合驱动特征的宇宙学演化。
AI 中文摘要
星系合并可以将气体驱动至星系核，从而增强并合后星系中的恒星形成和黑洞吸积。在此，我们使用IllustrisTNG-50模拟以及BRAHMA模拟套件中的两个盒子（它们均采用不同的黑洞形成模型），来刻画候选大质量黑洞（MBH）对宿主中与并合相关的特征。在所有三个模拟中，我们选择其前身星系均拥有MBH的并合后星系，并量化它们相对于匹配的非并合对照星系在恒星形成和黑洞吸积方面的增强。在TNG50中，我们发现$0 \leq z < 3.3$范围内，比恒星形成率（sSFR）和比黑洞吸积率（sBHAR）均存在显著的并合触发增强，分别达到对照星系的约$1.4\times$和约$1.5-1.7\times$。BRAHMA运行采用了更具物理动机的种子形成模型，在比TNG50更低质量的星系和更高红移处播种黑洞。在BRAHMA中，$z \lesssim 3.3$时sSFR和气体分数的并合驱动增强与TNG50相当，并持续到BRAHMA所探测的最高红移（$z \sim 6$）。尽管如此，BRAHMA在其整个红移范围内未显示出sBHAR的显著并合驱动增强。类似地，TNG50对宿主相对于匹配对照星系显示出增强的AGN比例，而BRAHMA仅在吸积最快的大质量黑洞中显示出微弱的超额。
英文摘要
Galaxy mergers can drive gas toward galactic nuclei, enhancing both star formation and black hole accretion in post-merger galaxies. Here we use the IllustrisTNG-50 simulation and two boxes from the BRAHMA simulation suite, all of which adopt different black hole formation models, to characterize merger-associated signatures in candidate massive black hole (MBH)-pair hosts. In all three simulations, we select post-merger galaxies whose progenitors both host MBHs and quantify their enhancements in star formation and black hole accretion relative to matched non-merging controls. In TNG50, we find substantial merger-triggered enhancements in both specific star formation rate (sSFR) and specific black hole accretion rate (sBHAR) at $0 \leq z < 3.3$, reaching $\sim 1.4\times$ and $\sim 1.5-1.7\times$ the controls, respectively. The BRAHMA runs employ more physically motivated seed formation models, seeding BHs in lower-mass galaxies and at higher redshifts than TNG50. In BRAHMA, merger-driven enhancements in sSFR and gas fractions are comparable to those in TNG50 at $z \lesssim 3.3$ and persist to the highest redshifts probed by BRAHMA ($z \sim 6$). Despite this, BRAHMA shows no significant merger-driven enhancement in sBHAR across its entire redshift range. In a similar vein, TNG50 pair hosts show an enhanced AGN fraction relative to matched controls, whereas BRAHMA shows only a weak excess among the most rapidly accreting MBHs.
Comments19 pages, 9 figures, 1 table. Submitted to ApJ. Comments are welcome
