Puzzling outer-density profile of the dark matter halo in the Andromeda galaxy
Puzzling outer-density profile of the dark matter halo in the Andromeda galaxy
复制标题
仙女座星系暗物质晕令人费解的外密度剖面
DOI：
10.1093/pasj/psu124
复制
发表时间：
2014
影响因子：
2.3
通讯作者：
Masao Mori
中科院分区：
文献类型：
--
作者：
Takanobu Kirihara;Yohei Miki;Masao Mori
冷暗物质（CDM）宇宙学是宇宙结构形成的标准理论，它预言暗物质晕的外密度分布随离中心距离的立方而减小。然而，到目前为止，没有太多的努力已经花费在检查这一假设。在仙女座星系晕（M31）中，最近观测到的大尺度恒星结构为研究暗物质晕的质量密度分布提供了一个潜在的窗口。利用N体模拟方法研究了M31中暗物质晕的密度结构。为了再现仙女座巨南流和M31东西两侧的恒星壳层，我们找到了暗物质晕外密度分布的幂律指数α的充分条件.最佳拟合参数为α = −3.7，比CDM预测的更陡。
The cold dark matter (CDM) cosmology, which is the standard theory of the structure formation in the universe, predicts that the outer density profile of dark matter halos decreases with the cube of distance from the center. However, so far not much effort has been expended in examining this hypothesis. In the halo of the Andromeda galaxy (M 31), large-scale stellar structures detected by the recent observations provide a potentially suitable window to investigate the mass-density distribution of the dark matter halo. We explore the density structure of the dark matter halo in M 31 using anN-body simulation of the interaction between an accreting satellite galaxy and M 31. To reproduce the Andromeda Giant Southern Stream and the stellar shells at the east and west sides of M 31, we find the sufficient condition for the power-law index α of the outer density distribution of the dark matter halo. The best-fitting parameter is α = −3.7, which is steeper than the CDM prediction.