Primordial Dark Matter Halos and the Present Mass Distributions of Galaxies

原始暗物质晕和当前星系的质量分布

• 批准号: 0908370
• 负责人: Eric McKenzie
• 金额: $ 16.4万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908370&HistoricalAwards=false
• 关键词: Primordial; Dark; Matter; Halos; Present

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Dr. McGaugh will continue his work to determine the masses of the different components of disk galaxies, in particular the stellar disk, the gaseous disk and the dark halo. He will assemble velocity-resolved maps in the H-alpha line of ionized gas and in neutral hydrogen, to measure the density of gas in the galaxy disk, and its velocity field, for about 100 disk galaxies with a wide range in properties. He will use near-infrared K-band images to determine the distribution of stellar mass, fitting the rotation curves to obtain the mass contributions of the different components. In the low-surface-brightness disks where the dark halo dominates the gravitational forces, he will use the measured velocity field to search for evidence of the steep inner cusp predicted by simulations with standard Cold Dark Matter. The larger sample of galaxies will be used to derive the initial halo mass profiles by proper treatment of adiabatic compression. Finally, he will calibrate an empirical mass-discrepancy--acceleration relation. The mass discrepancy is defined locally as the difference between the observed circular speed of rotation and that predicted from the gas and stars alone. This discrepancy is related to the orbital speed of disk material; the present study aims to characterize that relation better as a step towards understanding its origin.Dr McGaugh will continue his program of outreach to elementary-school children. He will distribute the data products and models from this study to the astronomical community on a web page.

该奖项由 2009 年美国复苏和再投资法案（公法 111-5）资助。麦高将继续他的工作，以确定盘状星系不同组成部分的质量，特别是恒星盘、气态盘和暗晕。 他将在电离气体的 H-α 线和中性氢中组装速度分辨图，以测量大约 100 个具有广泛特性的盘状星系的星系盘中气体的密度及其速度场。 他将使用近红外K波段图像来确定恒星质量的分布，拟合旋转曲线以获得不同成分的质量贡献。 在暗晕主导重力的低表面亮度圆盘中，他将使用测量的速度场来寻找通过标准冷暗物质模拟预测的陡峭内尖点的证据。 较大的星系样本将用于通过适当的绝热压缩处理来导出初始晕质量剖面。 最后，他将校准经验质量差异-加速度关系。 质量差异局部定义为观测到的圆周旋转速度与仅根据气体和恒星预测的圆周旋转速度之间的差异。这种差异与盘材料的轨道速度有关；目前的研究旨在更好地描述这种关系，作为理解其起源的一步。麦高博士将继续他对小学生的推广计划。 他将通过网页向天文学界分发本研究的数据产品和模型。