论文标题
Astraeus VII：电离时期星系的环境依赖性组装
Astraeus VII: The environmental-dependent assembly of galaxies in the Epoch of Reionization
论文作者
论文摘要
我们使用Astraeus（N体暗物质模拟中星系形成和电离的半数字辐射转移耦合）框架，我们探索了在电离时期期间环境密度和辐射反馈对星系组装及其宿主光晕的影响。 Astraeus框架使我们能够研究带有质量的星系的演变（$ \ rm 10^{8.2} m_ \ odot <m _ {\ rm h} <10^{13} {13} m_ \ odot $） CMPC}）^3 $）。我们发现：（i）存在一个质量和红移 - 依赖性的“特征”环境（$ {\ rm log}（1 +δ_a（m _ {\ rm h}，z），z）= 0.021 \ times（m _ {\ rm h} 10 $）在哪个星系中最有效地吸收暗物质，例如，$ z = 5 $的每一个Myr的质量为$ 0.2 \％$; （ii）次要和主要合并的数量及其对暗物质组装的贡献在所有红移中随着光环质量的增加而增加，并且大多与环境无关； （iii）在$ z = 5 $少数合并时，对暗物质组件的贡献略高（最多$ \ sim 10 \％$），而对于恒星组件，主要合并主导了未成年人的贡献，以$ m _ {\ rm h} \ sieldsim 10^{11.5} {11.5} m_ \ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ odot $ calaxies; （iv）在低质量星系中更多的辐射反馈淬灭星星形成（$ m _ {\ rm h} \ Lessim 10^{9.5} m_ \ odot $）在过度密集的环境中（$ {\ rm log}（\ rm log}（1+δ）> 0.5 $）;这是由他们的主要分支主导的，产生了恒星形成历史，其红移进化较慢。
Using the ASTRAEUS (semi-numerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dark matter simUlationS) framework, we explore the impact of environmental density and radiative feedback on the assembly of galaxies and their host halos during the Epoch of Reionization. The ASTRAEUS framework allows us to study the evolution of galaxies with masses ($\rm 10^{8.2}M_\odot < M_{\rm h} < 10^{13}M_\odot$) in wide variety of environment ($-0.5 < {\rm log}(1+δ) < 1.3$ averaged over $(2~{\rm cMpc})^3$). We find that : (i) there exists a mass- and redshift- dependent "characteristic" environment (${\rm log} (1+δ_a(M_{\rm h}, z)) = 0.021\times (M_{\rm h}/M_\odot)^{0.16} + 0.07 z -1.12$, up to $z\sim 10$) at which galaxies are most efficient at accreting dark matter, e.g at a rate of $0.2\%$ of their mass every Myr at $z=5$; (ii) the number of minor and major mergers and their contributions to the dark matter assembly increases with halo mass at all redshifts and is mostly independent of the environment; (iii) at $z=5$ minor mergers contribute slightly more (by up to $\sim 10\%$) to the dark matter assembly while for the stellar assembly, major mergers dominate the contribution from minor mergers for $M_{\rm h}\lesssim 10^{11.5}M_\odot$ galaxies; (iv) radiative feedback quenches star formation more in low-mass galaxies ($M_{\rm h} \lesssim 10^{9.5}M_\odot$) in over-dense environments (${\rm log}(1+δ) > 0.5$); dominated by their major branch, this yields star formation histories biased towards older ages with a slower redshift evolution.
