arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0705.2496gr-qcastro-ph
收藏

银河系暗物质对膜的体效应

Galactic dark matter as a bulk effect on the brane

C. G. Boehmer, T. Harko

摘要:

考虑了真空中沿膜上稳定圆轨道运动的试验粒子的角速度的行为。在膜世界的情况下,四维有效爱因斯坦方程获得额外的条款,分别称为暗辐射和暗压力,这是由于嵌入的3-膜在体。大量的独立观测表明,在星系周围受引力作用的测试粒子的旋转速度,作为到星系中心距离的函数,趋向于恒定值。在假设切向速度为常数的条件下,可以得到膜上真空引力场方程的精确解析形式的通解。这使我们能够获得显式形式的整体外尔张量在膜上的投影,以及作为暗辐射的函数的暗压力的状态方程。物理量和几何量用可观测/可测量的参数表示,如切向速度、重子质量和星系半径。我们还使用动力学系统定性分析的方法,通过假设一个简单的线性状态方程的暗压力的测试粒子的动力学分析。所得结果为膜世界模型预测的河外尺度观测检验提供了理论框架。

英文摘要:

The behavior of the angular velocity of a test particle moving in a stable circular orbit in the vacuum on the brane is considered. In the brane world scenario, the four dimensional effective Einstein equation acquire extra terms, called dark radiation and dark pressure, respectively, which arise from the embedding of the 3-brane in the bulk. A large number of independent observations have shown that the rotational velocities of test particles gravitating around galaxies tend, as a function of the distance from the galactic center, toward constant values. By assuming a constant tangential velocity, the general solution of the vacuum gravitational field equations on the brane can be obtained in an exact analytic form. This allows us to obtain the explicit form of the projections of the bulk Weyl tensor on the brane, and the equation of state of the dark pressure as a function of the dark radiation. The physical and geometrical quantities are expressed in terms of observable/measurable parameters, like the tangential velocity, the baryonic mass and the radius of the galaxy. We also analyze the dynamics of test particles by using methods from the qualitative analysis of dynamical systems, by assuming a simple linear equation of state for the dark pressure. The obtained results provide a theoretical framework for the observational testing at the extra-galactic scale of the predictions of the brane world models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑