MILKY WAY MASS AND POTENTIAL RECOVERY USING TIDAL STREAMS IN A REALISTIC HALO
MILKY WAY MASS AND POTENTIAL RECOVERY USING TIDAL STREAMS IN A REALISTIC HALO
复制标题
DOI：
10.1088/0004-637x/795/1/94
复制
发表时间：
2014-06
期刊：
影响因子：
--
通讯作者：
A. Bonaca;M. Geha;A. Kuepper;J. Diemand;K. Johnston;D. Hogg
中科院分区：
文献类型：
--
作者：
A. Bonaca;M. Geha;A. Kuepper;J. Diemand;K. Johnston;D. Hogg
本文提出了一种基于恒星潮汐流正演模拟的银河系引力势计算方法。我们用这种方法来测试的性能，光滑和静态的分析势代表现实的暗物质晕，其中有子结构，并不断发展的吸积。我们的FAST-FORWARD方法使用马尔可夫链蒙特卡罗算法比较，在六维相空间中，一个“观察到的”流的模型中创建的试验分析潜力。我们分析了一个大样本的流，通过Lactea II（VL2）模拟，这代表了一个现实的银河晕潜力。恢复的潜在参数是在协议的最佳拟合全球，当今VL2的潜力。然而，仅仅假设一个分析势限制了暗物质晕质量测量的精度为5%-20%，这取决于分析参数化的选择。总的来说，使用我们样本中的流进行的质量估计达到了这个基本极限，但单独使用时，它们可能会有很大的偏差。个别流可以下-和高估的质量，和偏见是逐步恶化的那些较小的perigalacticons，激励在银河系的距离大于70千秒差距的潮汐流的搜索。我们估计，在GD-1和Pal5类流的建模中，静态和平滑的暗物质潜力的假设在银河系质量估计中引入了高达50%的误差。
We present a new method for determining the Galactic gravitational potential based on forward modeling of tidal stellar streams. We use this method to test the performance of smooth and static analytic potentials in representing realistic dark matter halos, which have substructure and are continually evolving by accretion. Our FAST-FORWARD method uses a Markov Chain Monte Carlo algorithm to compare, in six-dimensional phase space, an “observed” stream to models created in trial analytic potentials. We analyze a large sample of streams that evolved in the Via Lactea II (VL2) simulation, which represents a realistic Galactic halo potential. The recovered potential parameters are in agreement with the best fit to the global, present-day VL2 potential. However, merely assuming an analytic potential limits the dark matter halo mass measurement to an accuracy of 5%–20%, depending on the choice of analytic parameterization. Collectively, the mass estimates using streams from our sample reach this fundamental limit, but individually they can be highly biased. Individual streams can both under- and overestimate the mass, and the bias is progressively worse for those with smaller perigalacticons, motivating the search for tidal streams at galactocentric distances larger than 70 kpc. We estimate that the assumption of a static and smooth dark matter potential in modeling of the GD-1- and Pal5-like streams introduces an error of up to 50% in the Milky Way mass estimates.