The Distribution of Mass in Spiral Galaxies

AST-0307417 Bershady PI将通过直接的运动学测量独立地确定附近正面螺旋星系的盘和晕成分的质量分布。 这样的决定是测试星系形成模型的核心。实际的观测是哈和恒星速度场和速度分散到几个磁盘尺度的长度。 正面系统有利地投影速度椭球的垂直分量，这与给定标度高度的圆盘的质量直接相关。 恒星尺度高度很好地估计，通过连接详细的运动学和光度学性质的边缘和面对的样品。 最近的发展，在大口径，积分场仪器的P.I.现在使所需的中等分辨率光谱学成为可能，并提供迄今为止独立测量磁盘质量和总质量的最佳机会。 这些对邻近星系的详细研究为以后使用10米和未来30米级望远镜观测和解释高红移系统提供了一个跳板。研究计划包括天文学研究、观测、数据分析特别是仪器仪表方面的研究生和本科生培训、公开讲座、WIYN 3.5米望远镜的基础设施改进、以及与南非和德国研究人员的国际合作。

AST-0307417BershadyThe PI will determine independently the mass distributions of the disk and halo components of nearby, face-on spiral galaxies through direct, kinematic measurements. Such determinations are central to testing galaxy formation models. The actual observations are Ha and stellar velocity fields and velocity dispersions out to several disk scale lengths. Face-on systems favorably project the vertical component of the velocity ellipsoid, which is directly related to the mass of a disk of a given scale-height. Stellar scale-heights are well estimated by linking detailed kinematic and photometric properties of edge-on and face-on samples. Recent developments in large-aperture, integral-field instrumentation by the P.I. now make possible the required medium resolution spectroscopy, and give the best opportunity to date to measure disk mass and total mass independently. These detailed studies of nearby galaxies provide a springboard for the later observation and interpretation of high redshift systems using 10m and future 30m-class telescopes.The research program includes graduate and undergraduate training in astronomical research, observation, data analysis and especially instrumentation, public lectures, infrastructure improvements for the WIYN 3.5m telescope, and international collaboration with South African and German researchers.