Constraining the dark matter halos of the Milky Way and Andomeda by µ-arcsecond VLBI Astrometry

利用 µ 角秒 VLBI 天体测量法约束银河系和 Andomeda 的暗物质晕

• 批准号: 5449766
• 负责人: Professor Dr. Karl M. Menten
• 金额: --
• 依托单位: Max-Planck-Institut für Radioastronomie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5449766?language=en
• 关键词: Constraining; dark; matter; halos; Milky

Key and still largely missing parameters for measuring the dark matter content and distribution of the Local Group are the proper motion vectors of its member galaxies. Currently, measurements of extragalactic proper motions by optical telescopes are limited to the most nearby companions of the Milky Way and have only provided marginal results, at best. On the other hand, by VLBI observations of bright maser sources, we have recently been able to detect extragalactic proper motions of two member galaxies of the Andromeda subgroup, M33 and 1C 10. These measurements comprising the first part of the present proposal, together with further research proposed here, will provide a decisive tool to distinguish between different models of the evolution of the Local Group. The long term goal of the project is to construct a full 3-D kinematic model of the Local Group. Also a geometric distance to M33 will be measured, ultimately to better than 5% accuracy by measuring the relative proper motions of three H20 maser sources on opposite sides of M33 and comparing them with the inclination and rotation speed of M33. This will allow also re-calibration of the extra-galactic distance scale based on Cepheids.The structure, dynamics, and the dark matter content of the Milky Way are very uncertain. The location and even the number of spiral arms is controversial, and values of the circular rotation speed (Өo) between 170 and 250 km s-1 are reported in the current literature. Most conclusions about the Galactic structure are based only on measurements of positions and radial velocities. Using VLBI. we can measure parallaxes accurate to 10 μas and proper motions to < 1 km s-1 out to distances of ≈ 10 kpc. As the second part of this proposal we plan to conduct observations that will locate the spiral arms of the Milky Way and constrain models of galactic rotation and the gravitational potential of the Milky Way. The observations will also test predictions made by spiral density wave theory, which is important for the formation and evolution of spiral galaxies in general.

测量本星系群暗物质含量和分布的关键参数是其成员星系的自行矢量，但仍然很大程度上缺失。目前，光学望远镜对河外自行的测量仅限于银河系最邻近的伴星，充其量只能提供边缘结果。另一方面，通过对亮脉泽源的VLBI观测，我们最近已经能够探测到仙女座星系群的两个成员星系M33和1C 10的河外自行。这些测量包括本提案的第一部分，再加上这里提出的进一步研究，将提供一个决定性的工具，以区分不同的模式的演变的本地集团。该项目的长期目标是建立一个完整的三维运动模型的本地组。此外，还将测量到M33的几何距离，通过测量M33相对两侧的三个H20脉泽源的相对自行，并将它们与M33的倾角和转速进行比较，最终达到优于5%的精度。这也将允许重新校准基于造父变星的银河系外距离尺度。银河系的结构，动力学和暗物质含量是非常不确定的。螺旋臂的位置甚至数量都是有争议的，目前文献中报道的圆周转速（170 - 250 km s-1）值。大多数关于银河系结构的结论仅仅基于位置和径向速度的测量。使用VLBI。我们可以测量到10 μ s的弛豫和小于1 km s-1的自行，测量距离为1000 kpc。作为该提案的第二部分，我们计划进行观测，以定位银河系的旋臂，并限制银河系旋转和银河系引力势的模型。这些观测还将检验螺旋密度波理论的预测，这对螺旋星系的形成和演化非常重要。

项目成果

TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. V. G23.01−0.41 AND G23.44−0.18

• DOI: 10.1088/0004-637x/693/1/424
• 发表时间: 2008-11
• 期刊: The Astrophysical Journal
• 作者: A. Brunthaler;M. Reid;K. Menten;X. Zheng;L. Moscadelli;Y. X. M. F. Radioastronomie;H. C. F. Astrophysics;N. University;O. Arcetri;Purple Mountain Observatory

THE DISTANCE TO A STAR-FORMING REGION IN THE OUTER ARM OF THE GALAXY

• DOI: 10.1088/0004-637x/696/2/1981
• 发表时间: 2009-01
• 期刊: The Astrophysical Journal
• 作者: K. Hachisuka;A. Brunthaler;K. Menten;M. Reid;Y. Hagiwara;N. Mochizuki

Limits on the Position Wander of Sgr A*

A* 中士位置漂移的限制

• DOI: 10.1086/588603
• 发表时间: 2008
• 期刊: The Astrophysical Journal
• 作者: Reid M.J;Broderick A.E;Loeb A;Honma M;Brunthaler A.
• 通讯作者: Brunthaler A.

TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. II. CEP A AND NGC 7538

• DOI: 10.1088/0004-637x/693/1/406
• 发表时间: 2008-11
• 期刊: The Astrophysical Journal
• 作者: L. Moscadelli;Mark J. Reid;K. Menten;A. Brunthaler;X. Zheng;Ye Xu;Ye Xu

A gravitationally lensed water maser in the early Universe

• DOI: 10.1038/nature07544
• 发表时间: 2008-12
• 期刊: Nature
• 影响因子: 64.8
• 作者: C. Impellizzeri;J. McKean;P. Castangia;A. Roy;C. Henkel;A. Brunthaler;O. Wucknitz