A novel approach to optimize the regularization and evaluation of dynamical models using a model selection framework
A novel approach to optimize the regularization and evaluation of dynamical models using a model selection framework
复制标题
使用模型选择框架优化动态模型正则化和评估的新方法
DOI：
--
复制
发表时间：
2021
影响因子：
4.8
通讯作者：
Jens Thomas
中科院分区：
文献类型：
--
作者：
Mathias Lipka;Jens Thomas
轨道叠加模型是一种非参数动力学建模技术，用于确定星系中心超大质量黑洞 (SMBH)、恒星或其暗物质晕的质量。主要问题之一是如何从基于不同假设质量分布的大量试验模型中决定哪个模型最能代表观测到的星系的真实结构。我们表明，仅根据模型的拟合优度来判断模型的传统方法可能会因模型灵活性的不同而导致估计的星系特性出现重大偏差。我们演示了如何使用引导迭代来估计模型的灵活性，并提出了一个模型选择框架，该框架通过在模型评估中考虑变量灵活性来消除这些偏差。我们扩展了模型选择方法，以直接从数据中优化正则化程度。总而言之，这导致建模技术的约束能力显着提高。我们通过模拟表明，人们可以根据完全解析的视线速度分布 (LOSVD) 的真实观测数据以百分之几的精度重建轴对称星系的质量、各向异性和视角。在第一个应用中，我们根据运动学数据重现了盘状星系 NGC 3368 倾角的光度估计，精度在 5° 以内，这些数据仅覆盖星系SMBH 周围的几个影响球半径。这证明了基于完全解析的 LOSVD 和模型选择框架的轨道模型可以实现的约束能力。
Orbit superposition models are a non-parametric dynamical modelling technique to determine the mass of a galaxy’s central supermassive black hole (SMBH), its stars, or its dark matter halo. One of the main problems is how to decide which model out of a large pool of trial models based on different assumed mass distributions represents the true structure of an observed galaxy best. We show that the traditional approach to judge models solely by their goodness-of-fit can lead to substantial biases in estimated galaxy properties caused by varying model flexibilities. We demonstrate how the flexibility of the models can be estimated using bootstrap iterations and present a model selection framework that removes these biases by taking the variable flexibility into account in the model evaluation. We extend the model selection approach to optimize the degree of regularization directly from the data. Altogether, this leads to a significant improvement of the constraining power of the modelling technique. We show with simulations that one can reconstruct the mass, anisotropy, and viewing angle of an axisymmetric galaxy with a few per cent accuracy from realistic observational data with fully resolved line-of-sight velocity distributions (LOSVDs). In a first application, we reproduce a photometric estimate of the inclination of the disc galaxy NGC 3368 to within 5° accuracy from kinematic data that cover only a few sphere-of-influence radii around the galaxy’s SMBH. This demonstrates the constraining power that can be achieved with orbit models based on fully resolved LOSVDs and a model selection framework.
DOI：
10.1111/j.1365-2966.2008.13754.x
发表时间：
2008-05
影响因子：
4.8
作者：
M. Cappellari
通讯作者：
M. Cappellari
DOI：
10.1111/j.1365-2966.2009.16167.x
发表时间：
2009-12
影响因子：
4.8
作者：
N. Nowak;Jens Thomas;P. Erwin;R. Saglia;R. Bender;R. Davies
通讯作者：
N. Nowak;Jens Thomas;P. Erwin;R. Saglia;R. Bender;R. Davies
DOI：
10.3847/1538-4357/ab6f71
发表时间：
2020-01
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Christopher M. Liepold;Matthew E. Quenneville;Chung-Pei Ma;J. Walsh;N. McConnell;J. Greene;J. Blakeslee
通讯作者：
Christopher M. Liepold;Matthew E. Quenneville;Chung-Pei Ma;J. Walsh;N. McConnell;J. Greene;J. Blakeslee