Mass Distribution Within Spiral Galaxies

螺旋星系内的质量分布

• 批准号: 1211793
• 负责人: Jerry Sellwood
• 金额: $ 40.22万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1211793&HistoricalAwards=false
• 关键词: Mass; Distribution; Within; Spiral; Galaxies

As astrophysicists expand their knowledge of the formation and evolution of the Universe, tying large-scale cosmological galaxy formation scenarios to the measured and inferred details of individually observed galaxies has become increasingly feasible. This project is an integrated program of observational and theoretical studies designed to determine the distribution of both dark and luminous matter within a large sample of spiral galaxies and to compare these measurements with the predictions of galaxy formation in the concordance cosmological model.Using the wide-field spectroscopic imaging Fabry-Perot instrument on the Southern African Large Telescope, the investigators propose to obtain high-resolution velocity maps of the galaxies, supplemented with more extended but lower resolution 21-cm maps from the Jansky Very Large Array (VLA) and, later, MeerKAT (Karoo Array Telescope). Combined with optical and near-infrared surface photometry, these data will be the basis for measurement of the total mass distribution within each galaxy. Stellar population synthesis estimates and detailed hydrodynamical modeling will determine the separation into baryonic and dark matter components. Extensive N-body simulations will test the stability of the models, sharpening the determination of the separate contributions of luminous and dark matter. After correction for the gravitational compression by the baryonic disk, the density, concentration, and circular speed of these halo models will be compared to the expected values derived from cosmological simulations. Discrepancies may suggest ways to improve and extend the physics in the galaxy formation simulations. A new analysis tool will measure non-axisymmetric patterns of motion in the two-dimensional kinematic maps of the galaxies, leading to a determination of the shapes of the dark halos. The investigators will also use Fabry-Perot observations of stellar absorption lines in early-type barred disk galaxies to determine the bar's rotation speed. As dynamical friction with the halo slows the bar's motion, this measurement will yield another constraint on the halo density in these galaxies. Sharpened by dynamical constraints, estimates for the mass-to-light ratios of galaxies aim to refine the poorly-known relation between mass-to-light and broad-band colors of disk galaxies.Educationally, the proposing team will disseminate their results to the broader community through public lectures and in New Jersey schools. They will involve undergraduate and graduate students in their research and mentor them in their professional development in the sciences.

随着天体物理学家的了解，他们对宇宙的形成和演变的了解，将大规模的宇宙星系形成场景绑定到所测量和推断的单个观察到星系的细节变得越来越可行。 This project is an integrated program of observational and theoretical studies designed to determine the distribution of both dark and luminous matter within a large sample of spiral galaxies and to compare these measurements with the predictions of galaxy formation in the concordance cosmological model.Using the wide-field spectroscopic imaging Fabry-Perot instrument on the Southern African Large Telescope, the investigators propose to obtain high-resolution velocity maps of the galaxies,从Jansky（VLA）和后来的Meerkat（Karoo Array TeleScope）中补充了更扩展但更低的分辨率21厘米地图。 结合光学和近红外表面光度法，这些数据将是测量每个星系内总质量分布的基础。 恒星种群的综合估计值和详细的流体动力模型将确定分解为重型和暗物质成分。 广泛的N体模拟将测试模型的稳定性，从而确定发光和暗物质的单独贡献的确定。 在通过重型磁盘校正重力压缩后，将将这些光环模型的密度，浓度和圆速度与宇宙学模拟得出的预期值进行比较。 差异可能会提出改善和扩展星系形成模拟物理学的方法。 一个新的分析工具将测量星系的二维运动图中的非轴对称运动模式，从而确定了暗光晕的形状。 研究人员还将在早期型磁盘星系中使用Fabry-Perot观察结果，以确定条形的旋转速度。 随着用光环的动力摩擦减慢了条的运动，该测量将对这些星系中的光晕密度产生另一个限制。 通过动态约束，对星系的质量比率的估计值得到了加强，旨在完善磁盘星系的质量到光线和宽带颜色之间鲜为人知的关系。教育方面，提议团队将通过公共讲座和新泽西州的学校和新泽西州的学校将其结果传播给更广泛的社区。 他们将使本科生和研究生参与研究，并指导他们在科学领域的专业发展中。