论文标题
提取星系合并时间标准II：一种新的拟合公式
Extracting Galaxy Merger Timescales II: A new fitting formula
论文作者
论文摘要
根据其轨道参数和宿主的结构属性，预测合并暗物质光环的合并时间尺度（$τ_ {\ rm Merge} $）是重力动态的基本问题，这对我们对宇宙学结构形成和星系形成的理解具有重要的后果。与宇宙学$ n $ body模拟的结果相比，以前预测$τ_ {\ rm Merge} $的模型已显示出不同程度的成功。我们以先前的工作为基础，并为$τ_ {\ rm Merge} $提出了一个新模型，该模型借鉴了从这些仿真中得出的见解。 We find that published predictions can provide reasonable estimates for $τ_{\rm merge}$ based on orbital properties at infall, but tend to underpredict $τ_{\rm merge}$ inside the host virial radius ($R_{200}$) because tidal stripping is neglected, and overpredict it outside $R_{200}$ because the host mass is被低估了。此外，我们发现，通过圆形半径$ r _ {\ rm Circ} $下调（过度预测）$τ_{\ rm Merge} $用于BOND（UNBOND）系统的模型。通过拟合$τ_ {\ rm Merge} $的依赖性对各种轨道和主机halo属性，我们得出了一个改进的模型，用于$τ_ {\ rm Merge} $，可以将其应用于其Orbit的任何点上的合并光晕。最后，我们简要讨论了新模型对$τ_ {\ rm Merge} $对于半分析星系建模的含义。
Predicting the merger timescale ($τ_{\rm merge}$) of merging dark matter halos, based on their orbital parameters and the structural properties of their hosts, is a fundamental problem in gravitational dynamics that has important consequences for our understanding of cosmological structure formation and galaxy formation. Previous models predicting $τ_{\rm merge}$ have shown varying degrees of success when compared to the results of cosmological $N$-body simulations. We build on this previous work and propose a new model for $τ_{\rm merge}$ that draws on insights derived from these simulations. We find that published predictions can provide reasonable estimates for $τ_{\rm merge}$ based on orbital properties at infall, but tend to underpredict $τ_{\rm merge}$ inside the host virial radius ($R_{200}$) because tidal stripping is neglected, and overpredict it outside $R_{200}$ because the host mass is underestimated. Furthermore, we find that models that account for orbital angular momentum via the circular radius $R_{\rm circ}$ underpredict (overpredict) $τ_{\rm merge}$ for bound (unbound) systems. By fitting for the dependence of $τ_{\rm merge}$ on various orbital and host halo properties,we derive an improved model for $τ_{\rm merge}$ that can be applied to a merging halo at any point in its orbit. Finally, we discuss briefly the implications of our new model for $τ_{\rm merge}$ for semi-analytical galaxy formation modelling.
