A possible formation scenario for dwarf spheroidal galaxies - II. A parameter study
A possible formation scenario for dwarf spheroidal galaxies - II. A parameter study
复制标题
矮椭球星系可能的形成情景 - II。
DOI：
10.1093/mnras/stt1448
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发表时间：
2013
影响因子：
4.8
通讯作者：
Assmann P
中科院分区：
文献类型：
--
作者：
Assmann P
在Lambda冷暗物质分级宇宙学模型中，矮球星系被认为是星系形成过程的基本构件。这些星系被认为是已知的暗物质(DM)最多的星系，恒星含量最低，气体含量也最低。许多理论试图解释dSph星系的形成，借助于这样一个事实，即这些星系主要围绕着大星系运行，或者调用了其他相互作用机制。在这里，我们展示了一套完整的模拟作为我们的基准模型的扩展，在这个模型中，我们通过溶解矮小星系Dm晕中的星团来孤立地研究经典dSph星系的形成。在我们的参数调查中，我们采用了核心型和尖型DM晕廓线，并考虑了不同数量的溶解星团。研究了不同质量、不同尺度长度的DM晕和不同的恒星形成效率对可观测量的依赖关系。我们发现，我们提出的方案解释了银河系经典dSph星系的许多特征，如它们的形态和动力学。我们看到了发光组件的表面亮度和比例长度随模拟参数变化的趋势。我们还确定了形状上的不规则性，即笨拙和椭圆度在我们的模拟中是如何变化的。在速度空间中，我们确定了导致速度弥散曲线平坦的参数。我们识别速度空间中运动学上冷冷的子结构，称为化石残留物，源于我们独特的初始条件，它改变了预期的结果。这些流动运动被认为是未来高分辨率观测的关键特征，以验证我们的假设。
Dwarf spheroidal (dSph) galaxies are considered the basic building blocks of the galaxy formation process in the Lambda cold dark matter hierarchical cosmological model. These galaxies are believed to be the most dark matter (DM) dominated systems known, have the lowest stellar content and are poor in gas. Many theories attempt to explain the formation of dSph galaxies resorting to the fact that these galaxies are mainly found orbiting large galaxies or invoking other mechanisms of interactions. Here, we show the full set of simulation as an extension of our fiducial model, where we study the formation of classical dSph galaxies in isolation by dissolving star clusters within the DM halo of the dwarf galaxy. In our parameter survey, we adopt cored and cusped DM halo profiles and consider different numbers of dissolving star clusters. We investigate the dependence of observable quantities with different masses and scalelengths of the DM halo and different star formation efficiencies. We find that our proposed scenario explains many features of the classical dSph galaxies of the Milky Way, like their morphology and their dynamics. We see trends how the surface brightness and the scalelength of the luminous component vary with the parameters of our simulations. We also identify how irregularities in their shape, i.e. clumpiness and ellipticity vary in our simulations. In velocity space, we identify the parameters leading to flat velocity dispersions curves. We recognize kinematically cold substructures in velocity space, named fossil remnants and stemming from our unique initial conditions, which alter the expected results. These streaming motions are considered as a key feature for future observation with high resolution to validate our scenario.