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arXiv 2311.13639astro-ph.GAastro-ph.CO
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并非所有子晕都生而平等:在TNG50中模拟子晕密度剖面的多样性

Not All Subhaloes Are Created Equal: Modelling the Diversity of Subhalo Density Profiles in TNG50

Felix M. Heinze, Giulia Despali, Ralf S. Klessen

AI总结:

分析了TNG50模拟中子晕密度剖面,发现常用模型拟合不佳,提出改进的三参数NFW模型显著提升拟合优度,并给出参数随子晕属性变化的标度关系以预测受重子影响的子晕性质。

摘要:

在这项工作中,我们分析了TNG50模拟中质量为 $M_\mathrm{sh} \geq 1.4 \times 10^8$ M$_\odot$ 的子晕的密度剖面,旨在包含重子效应。我们评估了常用模型的性能,例如标准NFW、Einasto以及NFW剖面的平滑截断版本。我们发现这些模型对大多数子晕表现不佳,其中NFW剖面在大多数情况下拟合最差。这主要是由于内部和外部对数斜率不匹配,在存在重子的情况下,大量子晕的这些斜率明显更陡。为了解决这个问题,我们提出了新的三参数模型,并表明它们显著提高了拟合优度,且独立于子晕的特定属性。我们表现最佳的模型是NFW剖面的修改版本,具有内部对数斜率-2和可变截断,比标准NFW剖面中的斜率过渡更尖锐、更陡峭。此外,我们研究了最佳密度剖面模型的参数值和平均密度剖面如何随子晕质量、$V_\mathrm{max}$、距宿主晕中心的距离、重子含量和落入时间变化,并给出了各个剖面平均参数的显式标度关系。新提出的拟合和标度关系可用于预测质量范围 $10^8$ M$_\odot$ $\leq M_\mathrm{sh} \leq$ $10^{13}$ M$_\odot$ 内可能受重子影响的现实子晕的性质。

英文摘要:

In this work, we analyse the density profiles of subhaloes with masses $M_\mathrm{sh} \geq 1.4 \times 10^8$ M$_\odot$ in the TNG50 simulation, with the aim of including baryonic effects. We evaluate the performance of frequently used models, such as the standard NFW, the Einasto, and a smoothly truncated version of the NFW profile. We find that these models do not perform well for the majority of subhaloes, with the NFW profile giving the worst fit in most cases. This is primarily due to mismatches in the inner and outer logarithmic slopes, which are significantly steeper for a large number of subhaloes in the presence of baryons. To address this issue, we propose new three-parameter models and show that they significantly improve the goodness of fit independently of the subhalo's specific properties. Our best-performing model is a modified version of the NFW profile with an inner log-slope of -2 and a variable truncation that is sharper and steeper than the slope transition in the standard NFW profile. Additionally, we investigate how both the parameter values of the best density profile model and the average density profiles vary with subhalo mass, $V_\mathrm{max}$, distance from the host halo centre, baryon content and infall time, and we also present explicit scaling relations for the mean parameters of the individual profiles. The newly proposed fit and the scaling relations are useful to predict the properties of realistic subhaloes in the mass range $10^8$ M$_\odot$ $\leq M_\mathrm{sh} \leq$ $10^{13}$ M$_\odot$ that can be influenced by the presence of baryons.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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