The Distribution of Mass in Spiral Galaxies

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圆盘和光晕组成部分的质量分布。这些决定对于测试星系形成模型至关重要。实际观测到的是Ha和恒星的速度场，以及数个盘级长度的速度弥散。正面系统有利于投影速度椭球体的垂直分量，这与给定尺度高度的圆盘质量直接相关。恒星比例尺的高度可以很好地通过连接边缘和正面样品的详细运动学和光度特性来估计。P.I.在大孔径、积分场仪器方面的最新发展，使所需的中分辨率光谱学成为可能，并为迄今为止独立测量圆盘质量和总质量提供了最好的机会。这些对附近星系的详细研究为随后使用10米和未来30米级望远镜观察和解释高红移系统提供了一个跳板。该研究项目包括天文研究、观测、数据分析（尤其是仪器）、公共讲座、WIYN 3.5m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方面的研究生和本科生培训。

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.