Alexander V. Khoperskov, S. Khrapov, Danila S. Sirotin
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引用次数: 0
摘要
我们详细研究了一个矮盘星系与一个银河系类型的大质量螺旋星系合并的动力学过程。在卫星多次穿过主星系的圆盘之后,这种相互作用的残留物是一个紧凑的恒星核心,其特征接近于小型紧凑椭圆星系(cE)或大型超紧凑矮星(UCD)。这种有效半径为 100-200 pc 的 cE/UCD 过渡天体是矮盘星系毁灭过程中剥离恒星核心外层的结果。相互作用前卫星的数值模型包括重子物质(恒星和气体)和暗物质。我们用 N-body 来描述恒星和暗物质的动力学,用平滑粒子流体力学来模拟两个星系的气体成分。直接计算所有粒子之间引力的方法提供了高达 10 pc 的空间结构定性分辨率。矮星系几乎是沿着一条具有较大偏心率的径向轨迹落到主星系的气体和恒星盘上的。这就确保了矮星系在超过 90 亿年的时间间隔内,在每次接近主星系圆盘时都会穿过主星系的圆盘。我们在很大范围内改变了卫星的气体质量和初始轨道特性,研究了核心质量损失的特征。矮星系中初始气体成分的存在极大地影响了紧凑型恒星核心的形成和演化性质。与合并后不含气体的矮星系相比,富含气体的卫星会产生一个更紧凑的椭圆星系。卫星的初始气体含量也会影响剥离核的内部旋转。模拟的 cE/UCD 星系在演化结束时只含有很少的气体和暗物质。
Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers
The dynamics of the merger of a dwarf disc galaxy with a massive spiral galaxy of the Milky Way type were studied in detail. The remnant of such interaction after numerous crossings of the satellite through the disc of the main galaxy was a compact stellar core, the characteristics of which were close to small compact elliptical galaxies (cEs) or large ultra-compact dwarfs (UCDs). Such transitional cE/UCD objects with an effective radius of 100–200 pc arise as a result of stripping the outer layers of the stellar core during the destruction of a dwarf disc galaxy. Numerical models of the satellite before interaction included baryonic matter (stars and gas) and dark mass. We used N-body to describe the dynamics of stars and dark matter, and we used smoothed-particle hydrodynamics to model the gas components of both galaxies. The direct method of calculating the gravitational force between all particles provided a qualitative resolution of spatial structures up to 10 pc. The dwarf galaxy fell onto the gas and stellar discs of the main galaxy almost along a radial trajectory with a large eccentricity. This ensured that the dwarf crossed the disc of the main galaxy at each pericentric approach over a time interval of more than 9 billion years. We varied the gas mass and the initial orbital characteristics of the satellite over a wide range, studying the features of mass loss in the core. The presence of the initial gas component in a dwarf galaxy significantly affects the nature of the formation and evolution of the compact stellar core. The gas-rich satellite gives birth to a more compact elliptical galaxy compared to the merging gas-free dwarf galaxy. The initial gas content in the satellite also affects the internal rotation in the stripped nucleus. The simulated cE/UCD galaxies contained very little gas and dark matter at the end of their evolution.
GalaxiesPhysics and Astronomy-Astronomy and Astrophysics
CiteScore
4.90
自引率
12.00%
发文量
100
审稿时长
11 weeks
期刊介绍:
Es una revista internacional de acceso abierto revisada por pares que proporciona un foro avanzado para estudios relacionados con astronomía, astrofísica y cosmología. Areas temáticas Astronomía Astrofísica Cosmología Astronomía observacional: radio, infrarrojo, óptico, rayos X, neutrino, etc. Ciencia planetaria Equipos y tecnologías de astronomía. Ingeniería Aeroespacial Análisis de datos astronómicos. Astroquímica y Astrobiología. Arqueoastronomía Historia de la astronomía y cosmología. Problemas filosóficos en cosmología.