标题： M31暗物质分布的数值分析 显示英文标题

标题： Numerical analyses of M31 dark matter profiles

摘要： 我们通过考虑仙女座星系（M31）的核球、盘和晕的各组成部分来重现其旋转曲线，并认为晕包含了大部分暗物质质量。 因此，我们的处理方法是将星系核球分为两个部分，即内核球和主核球。 这两个核球都通过指数密度分布来建模，因为我们强调广泛接受的de Vaucouleurs定律无法再现整个星系核球的旋转曲线。 此外，我们采用多种广为人知的暗物质经验分布来估算晕区域内的暗物质质量。 而且，我们应用最小二乘拟合方法，利用旋转曲线的速度和半径数据点来确定模型的自由参数，即特征（中心）密度、尺度半径以及总质量。 为此，我们基于Metropolis算法进行了基于马尔可夫链蒙特卡洛统计分析，最大化我们的似然函数。 我们不是单独拟合核球、盘和晕的各组成部分，而是对所有组成部分进行整体拟合并使用所有数据点。 因此，我们批判性地分析了相应的结果，特别是采用了贝叶斯信息准则来评估描述M31暗物质动力学最可信的模型。 显示英文摘要

摘要： We reproduce the rotation curve of the Andromeda galaxy (M31) by taking into account its bulge, disk, and halo components, considering the last one to contain the major part of dark matter mass. Hence, our prescription is to split the galactic bulge into two components, namely, the inner and main bulges, respectively. Both bulges are thus modeled by exponential density profiles since we underline that the widely accepted de Vaucouleurs law fails to reproduce the whole galactic bulge rotation curve. In addition, we adopt various well-known phenomenological dark matter profiles to estimate the dark matter mass in the halo region. Moreover, we apply the least-squares fitting method to determine from the rotation curve the model free parameters, namely, the characteristic (central) density, scale radius, and consequently the total mass. To do so, we perform Markov chain Monte Carlo statistical analyses based on the Metropolis algorithm, maximizing our likelihoods adopting velocity and radii data points of the rotation curves. We do not fit separately the components for bulges, disk and halo, but we perform an overall fit including all the components and employing all the data points. Thus, we critically analyze our corresponding findings and, in particular, we employ the Bayesian Information Criterion to assess the most accredited model to describe M31 dark matter dynamics.