The distribution of mass in dwarf galaxies and the structure of their ISM

矮星系的质量分布及其ISM结构

• 批准号: 41632553
• 负责人: Professor Dr. Ulrich Klein
• 金额: --
• 依托单位: Abteilung Radioastronomie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/41632553?language=en
• 关键词: distribution; mass; dwarf; galaxies; structure

Central to this project is the efficient use of the Very Large Array (VLA) to carry out HI measurements of the disks of a carefully selected sample of low-mass (or dwarf) and gas-rich galaxies down to very low column densities and with high spectral resolution. Their stellar disks will be investigated with deep near-infrared (NIR) photometry, mainly using the INT at La Palma. The science goals, which naturally arise from our (and others ) previous studies, are as follows:- The overall gravitational potential will be explored by deriving high-quality rotation curves. This facilitates a mass decomposition into the (stellar and gaseous) baryonic and Dark Matter (DM). - The sizes of the gaseous disks, not very well known for dwarf galaxies, will be explored down to the lowest gas column densities achievable. This is the only means to estimate the total size and mass of this kind of galaxies. The sizes of the stellar disks will be determined using NIR photometry. These will be compared to the sizes of the gas disks.- The radio and optical observations will also be conveniently used to carry out mass decompositions, thereby studying the distribution of the baryonic and dark matter constituents.- The structure of the interstellar medium (ISM) will be investigated using the HI data cubes. In particular, the statistics of HI holes will be established, and their size distribution be studied with respect to the disk thicknesses and depth of gravitational potentials.- Using the surface mass densities of the stellar and gaseous constituents, the conditions for (past and future) star formation will be assessed via the Toomre criterion. This will shed light on the lack of star formation in the outer gaseous disks.These measurements and analyses will be efficiently combined such as to achieve an overall understanding of the nature of gas-rich dwarf galaxies. The derived mass distributions and gravitational potentials deliver boundary conditions for the structure of the gaseous disks, i.e. their thickness and size distribution of bubbles. Achieving this goal is facilitated by our newly developed software tools, which allows to derive the three-dimensional structure of the gaseous disks. Furthermore, the relation between the size of the stellar and gaseous disk will be extended to the low-mass end of galaxies. It is the for the first time that such a systematic study will be conducted.

该项目的核心是对非常大的阵列（VLA）的有效利用来对精心选择的低质量（或矮人）和富含气体的星系的磁盘进行HI测量，并以高光谱分辨率进行高柱密度。他们的恒星磁盘将通过深近红外（NIR）光度法进行研究，主要是使用La Palma的INT。自然是由我们（和其他）以前的研究产生的科学目标如下： - 通过得出高质量旋转曲线，将探索总体引力电位。这促进了质量分解（恒星和气态）的重生和暗物质（DM）。 - 气体磁盘的尺寸，并不是矮星系闻名，将被探索到可实现的最低气柱密度。这是估计这种星系的总规模和质量的唯一手段。恒星磁盘的尺寸将使用NIR光度法确定。这些将与气盘的尺寸进行比较。-无线电和光学观察结果也将方便地用于执行质量分解，从而研究了Baryonic和暗物质成分的分布。-使用HI Data Ciotes研究了星际介质（ISM）的结构。特别是，将建立HI孔的统计数据，并研究其尺寸分布相对于磁盘厚度和重力电位深度。-使用恒星和气态成分的表面质量密度，（过去和未来）星形形成的条件将通过Toomre Criterion进行评估。这将阐明外部气体盘缺乏恒星形成。这些测量和分析将有效地组合，例如对富含气体富含气体的矮星系的性质的整体理解。派生的质量分布和重力电势为气态磁盘结构（即它们的气泡的厚度和尺寸分布）提供边界条件。我们新开发的软件工具促进了实现这一目标，该工具允许得出气体磁盘的三维结构。此外，恒星和气体磁盘的大小之间的关系将扩展到星系的低质量端。这是第一次将进行这样的系统研究。