Can the galactic rotation curves be explained in brane world models
Can the galactic rotation curves be explained in brane world models
复制标题
银河系旋转曲线可以用膜世界模型来解释吗
DOI：
10.1103/physrevd.70.024010
复制
发表时间：
2004
影响因子：
5
通讯作者：
T. Harko
中科院分区：
文献类型：
--
作者：
M. Mak;T. Harko
我们考虑膜世界场景中真空中静态球对称引力场方程的共角对称解。假设产生对称性的矢量场是非静态的，以共形因子为参数，可以得到膜上场方程的通解，其为精确的参数形式。作为所获得的解决方案的物理应用，我们考虑在稳定圆形轨道上移动的测试粒子的角速度的行为。在这种情况下，切向速度可以仅表示为共形因子和一些积分常数的函数。对于特定范围的积分常数，在大径向距离的限制下，测试颗粒的切向速度趋于恒定值。这种行为特定于星系旋转曲线，通常通过引用暗物质假设来解释。测试粒子的角速度的极限值可以作为星系重子质量和半径的函数来获得。还详细考虑了暗辐射和暗压力项的行为，并且表明它们可以用测试粒子的旋转速度来表示。因此，当前模型的所有预测都可以通过观察来检验。因此，共形对称膜中主体的自由引力场产生的非局域效应的存在，可以为距银心较远的中性氢云的动力学提供解释。
We consider solutions with conformal symmetry of the static, spherically symmetric gravitational field equations in the vacuum in the brane world scenario. By assuming that the vector field generating the symmetry is nonstatic, the general solution of the field equations on the brane can be obtained in an exact parametric form, with the conformal factor taken as parameter. As a physical application of the obtained solutions we consider the behavior of the angular velocity of a test particle moving in a stable circular orbit. In this case the tangential velocity can be expressed as a function of the conformal factor and some integration constants only. For a specific range of integration constants, the tangential velocity of the test particle tends, in the limit of large radial distances, to a constant value. This behavior is specific to galactic rotation curves and is explained usually by invoking the hypothesis of dark matter. The limiting value of the angular velocity of the test particle can be obtained as a function of the baryonic mass and radius of the galaxy. The behavior of the dark radiation and dark pressure terms is also considered in detail, and it is shown that they can be expressed in terms of the rotational velocity of a test particle. Hence all the predictions of the present model can be tested observationally. Therefore the existence of the nonlocal effects, generated by the free gravitational field of the bulk in a conformally symmetric brane, may provide an explanation for the dynamics of the neutral hydrogen clouds at large distances from the galactic center.
影响因子：
5
作者：
A. Campos;C. Sopuerta
通讯作者：
A. Campos;C. Sopuerta