Suppressing Dwarf Galaxy Formation with Gravitational Pancakes

首席研究员和他的合作者将研究一种有希望的替代流行的星系形成冷暗物质模型的方法，在这种模型中，低质量晕周围的介质通过煎饼（片状宇宙结构）的形成而预热。与观测到的星系数量密度相比，冷暗物质模型通常预测了太多的低质量暗物质晕。初步分析表明，大质量煎饼的形成可能先于低质量晕的形成，并加热星系间介质，并证明这一过程可以对矮星系的数量产生重大影响。n体模拟和分析模型将用于详细研究光晕祖细胞和形成光晕的薄煎饼之间的关系。将进行全流体动力学模拟，以量化重力煎饼的直接预热及其对星系晕气体吸积的影响。这些结果将为解释来自地面和空间的主要观测项目的观测结果提供新的途径。拟议的项目还为研究生提供多学科培训机会，并有助于提高公众对国家科学基金会和其他资助机构支持的项目的兴趣。

The Principal Investigator and his collaborators will investigate a promising alternative to popular cold dark matter models of galaxy formation, a model in which the medium around low-mass halos is preheated by the formation of pancakes (sheet-like cosmic structures). Cold dark matter models in general predict too many low-mass dark matter halos compared to the observed number density of galaxies. A preliminary analysis suggests that the formation of massive pancakes may precede that of low-mass halos and heat the intergalactic medium, and demonstrates that such a process can have a significant effect on the number of dwarf galaxies. N-body simulations and analytical models will be used to study in detail the relationship between halo progenitors and the pancakes within which the halos form. Full hydrodynamical simulations will be carried out to quantify directly preheating by gravitational pancaking and its effect on gas accretion into galaxy halos. The results will provide new avenues for interpreting observations from major observational programs, both ground- and space based. The proposed projects also provide multidisciplinary training opportunities for graduate students, and help promote public interest in programs supported by the National Science Foundation and other funding agencies.