Stellar Dynamical Modeling—Counting Conserved Quantities  

作　　者：Richard J.Long Shude Mao Yougang Wang 

机构地区：[1]Department of Astronomy,Tsinghua University,Beijing 100084,China [2]Jodrell Bank Centre for Astrophysics,Department of Physics and Astronomy,The University of Manchester,Oxford Road,Manchester M139PL,UK [3]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [4]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Research in Astronomy and Astrophysics》2023年第5期198-212,共15页天文和天体物理学研究（英文版）

基　　金：partly supported by the National Key Basic Research and Development Program of China(No.2018YFA0404501 to Shude Mao);by the National Natural Science Foundation of China(NSFC,Grant Nos.11821303,11761131004 and 11761141012 to Shude Mao);support by the CAS Interdisciplinary Innovation Team(JCTD-2019-05)。

摘　　要：Knowing the conserved quantities that a galaxy’s stellar orbits conform to is important in helping us understand the stellar distribution and structures within the galaxy.Isolating integrals of motion and resonances are particularly important,non-isolating integrals less so.We compare the behavior and results of two methods for counting the number of conserved quantities,one based on the correlation integral approach and the other a more recent method using machine learning.Both methods use stellar orbit trajectories in phase space as their only input,and we create such trajectories from theoretical spherical,axisymmetric,and triaxial model galaxies.The orbits have known isolating integrals and resonances.We find that neither method is fully effective in recovering the numbers of these quantities,nor in determining the number of non-isolating integrals.From a computer performance perspective,we find the correlation integral approach to be the faster.Determining the algebraic formulae of(multiple)conserved quantities from the trajectories has not been possible due to the lack of an appropriate symbolic regression capability.Notwithstanding the shortcomings we have noted,it may be that the methods are usable as part of a trajectory analysis tool kit.

关 键 词：GALAXIES kinematics and dynamics-methods numerical-galaxies STRUCTURE 

分 类 号：P152[天文地球—天文学]