论文标题

半分析模型的下半钟轨道演化的新校准方法

A new calibration method of sub-halo orbital evolution for semi-analytic models

论文作者

Yang, Shengqi, Du, Xiaolong, Benson, Andrew J., Pullen, Anthony R., Peter, Annika H. G.

论文摘要

了解卫星光环的非线性动力学(又称“ sub-halos”)对于预测暗物质子结构和卫星星系的丰度和分布以及使用观测值之间的微物理暗物质模型之间的区分很重要。通常,对这些动力学进行建模需要高分辨率的大型N体模拟。半分析模型可以提供一种更有效的方法来描述关键物理过程,例如动态摩擦,潮汐质量损失和潮汐加热,只有几个自由参数。在这项工作中,我们提出了一种快速的蒙特卡洛马尔可夫链拟合方法,以探索这种亚halo非线性演化模型的参数空间。我们使用早期工作中描述的动态模型,并将模型校准为两组高分辨率的冷暗物质N体模拟,Elvis和Caterpillar。与以前使用手动参数调整的校准相比,我们的方法提供了一种更强大的方法来确定最佳拟合参数及其后验概率。我们发现,对于下半升质量和最大速度函数的共同拟合可以打破潮汐剥离和潮汐加热参数之间的堕落性,并为动态摩擦强度提供更好的约束。我们表明,我们的半分析模拟可以准确地重现N体仿真统计数据,并且两组N体模拟的校准结果在95%的置信水平上一致。在这项工作中校准的动力模型对于未来的暗物质亚结构研究将很重要。

Understanding the non-linear dynamics of satellite halos (a.k.a. "sub-halos") is important for predicting the abundance and distribution of dark matter substructures and satellite galaxies, and for distinguishing among microphysical dark matter models using observations. Typically, modeling these dynamics requires large N-body simulations with high resolution. Semi-analytic models can provide a more efficient way to describe the key physical processes such as dynamical friction, tidal mass loss, and tidal heating, with only a few free parameters. In this work, we present a fast Monte Carlo Markov Chain fitting approach to explore the parameter space of such a sub-halo non-linear evolution model. We use the dynamical models described in an earlier work and calibrate the models to two sets of high-resolution cold dark matter N-body simulations, ELVIS and Caterpillar. Compared to previous calibrations that used manual parameter tuning, our approach provides a more robust way to determine the best-fit parameters and their posterior probabilities. We find that jointly fitting for the sub-halo mass and maximum velocity functions can break the degeneracy between tidal stripping and tidal heating parameters, as well as providing better constraints on the strength of dynamical friction. We show that our semi-analytic simulation can accurately reproduce N-body simulations statistics, and that the calibration results for the two sets of N-body simulations agree at 95% confidence level. Dynamical models calibrated in this work will be important for future dark matter substructure studies.

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