arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1802.02606astro-ph.GA
收藏

基于Action的矮球状星系动力学模型：对天炉座的应用

Action-based dynamical models of dwarf spheroidal galaxies: application to Fornax

Raffaele Pascale, Lorenzo Posti, Carlo Nipoti, James Binney

备注：
Accepted 2018 July 6; Received 2018 June 1; Submitted in original to MNRAS form 2018 February 5
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们提出了新的动力学模型的矮球状星系（dSphs）中的恒星成分和暗晕的解析分布函数，依赖于行动积分描述。这些分布函数的最一般形式可以表示轴对称和可能旋转的恒星系统。在这里，作为第一个应用程序，我们模拟天炉座dSph，限制自己，为简单起见，非旋转，球形的情况下。该模型进行了比较与国家的最先进的光谱和光度观测的天炉座，利用知识的视线速度分布的模型和占前景污染的银河系。最适合天炉座结构和运动学特性的模型有一个核心暗晕，核心大小为$r_{\rm c}\simeq1.03$ kpc。在有效半径$R_{\rm eff} \simeq 0.62\,$ kpc内，暗亮质量比为$(M_{\rm dm}/M_{\star})|_{R_{\rm eff}}\simeq9.6$，在3 kpc内为$(M_{\rm dm}/M_{\star})|_{3 {\rm kpc}} \simeq 144$。恒星的速度分布是各向同性的光谱数据所涵盖的整个径向范围内，略径向各向异性的恒星分布的郊区。对于积分角$θ= 0.5^{\circ}$，暗物质湮灭$J$因子和衰变$D$因子分别为$\log_{10}(J$ $[$ GeV $^2$ cm $^{-5}])\simeq18.34$和$\log_{10}(D$ $[$ GeV cm $^{-2}])\simeq18.55$。这个天炉座的核心晕模型是首选的，具有较高的统计学意义，这两个模型与纳瓦罗，弗伦克和白色的黑暗晕和简单的质量跟随光模型。

英文摘要：

We present new dynamical models of dwarf spheroidal galaxies (dSphs) in which both the stellar component and the dark halo are described by analytic distribution functions that depend on the action integrals. In their most general form these distribution functions can represent axisymmetric and possibly rotating stellar systems. Here, as a first application, we model the Fornax dSph, limiting ourselves, for simplicity, to the non rotating, spherical case. The models are compared with state-of-the-art spectroscopic and photometric observations of Fornax, exploiting the knowledge of the line-of-sight velocity distribution of the models and accounting for the foreground contamination from the Milky Way. The model that best fits the structural and kinematic properties of Fornax has a cored dark halo, with core size $r_{\rm c}\simeq1.03$ kpc. The dark-to-luminous mass ratio is $(M_{\rm dm}/M_{\star})|_{R_{\rm eff}}\simeq9.6$ within the effective radius $R_{\rm eff} \simeq 0.62\,$kpc and $(M_{\rm dm}/M_{\star})|_{3 {\rm kpc}} \simeq 144$ within 3 kpc. The stellar velocity distribution is isotropic almost over the full radial range covered by the spectroscopic data and slightly radially anisotropic in the outskirts of the stellar distribution. The dark-matter annihilation $J$-factor and decay $D$-factor are, respectively, $\log_{10}(J$ $[$GeV$^2$ cm$^{-5}])\simeq18.34$ and $\log_{10}(D$ $[$GeV cm$^{-2}])\simeq18.55$, for integration angle $θ= 0.5^{\circ}$. This cored halo model of Fornax is preferred, with high statistical significance, to both models with a Navarro, Frenk and White dark halo and simple mass-follows-light models.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑