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arXiv 1004.0576gr-qcastro-ph.GAhep-th
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物质与几何非最小耦合修正引力下的银河系自转曲线

Galactic rotation curves in modified gravity with non-minimal coupling between matter and geometry

T. Harko

摘要:

我们调查的可能性,可以解释的框架下修改的重力模型与非最小的物质几何耦合的测试粒子的旋转速度的行为星系周围的引力。一般来说,星系周围的测试粒子的动力学,以及相应的质量赤字,是通过假设暗物质的存在来解释的。几何-物质耦合的引力场方程中的附加项修正了试验粒子的运动方程,并引入了附加引力相互作用。本文从描述粒子运动的非最小耦合变分原理出发,导出了在真空中球对称几何中沿稳定圆轨道运动的试验粒子的切向速度表达式。切向速度取决于度规张量分量,以及物质和几何之间的耦合函数。根据耦合函数,还得到了多普勒速度位移。如果切向速度分布是已知的,物质和几何之间的耦合项可以得到明确的解析形式。该函数的函数形式在两种情况下得到,对于恒定的切向速度,和从天文观测获得的经验速度分布,分别。因此,这些结果打开了直接测试修改后的重力模型与非最小的物质和几何之间的耦合,通过使用直接的天文和天体物理观测在银河系或河外尺度的可能性。

英文摘要:

We investigate the possibility that the behavior of the rotational velocities of test particles gravitating around galaxies can be explained in the framework of modified gravity models with non-minimal matter-geometry coupling. Generally, the dynamics of test particles around galaxies, as well as the corresponding mass deficit, is explained by postulating the existence of dark matter. The extra-terms in the gravitational field equations with geometry-matter coupling modify the equations of motion of test particles, and induce a supplementary gravitational interaction. Starting from the variational principle describing the particle motion in the presence of the non-minimal coupling, the expression of the tangential velocity of a test particle, moving in the vacuum on a stable circular orbit in a spherically symmetric geometry, is derived. The tangential velocity depends on the metric tensor components, as well as of the coupling function between matter and geometry. The Doppler velocity shifts are also obtained in terms of the coupling function. If the tangential velocity profile is known, the coupling term between matter and geometry can be obtained explicitly in an analytical form. The functional form of this function is obtained in two cases, for a constant tangential velocity, and for an empirical velocity profile obtained from astronomical observations, respectively. Therefore, these results open the possibility of directly testing the modified gravity models with non-minimal coupling between matter and geometry by using direct astronomical and astrophysical observations at the galactic or extra-galactic scale.

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。

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