标题： 广义相对论在MOND极限下的扩展预测了星系内外的新轨道结构 显示英文标题

标题： Extension of General Relativity with MOND limit predicts novel orbital structure in and around galaxies

摘要： 深入了解可以在特定星系势能中容纳的不同类型的恒星轨道，是使用例如施瓦西定理技术构建自洽模型的前提条件。 此外，星系的观测特性取决于这些轨道类别的性质以及系统中混沌的存在与否。 在现实情况下，建模的起点并不是引力势，而是观测到的密度分布时，我们需要一个引力理论来建立我们所看到的恒星与这些恒星可能的运动之间的联系。 这个论点可以反过来：理解每种引力理论允许什么样的轨道，可能会让我们更深入地了解这些理论，并找到测试它们的方法。 我们的目标是理解由最新扩展的MOND现象学进入相对论世界所预测的轨道的新特性。 我们在固定的密度分布中数值积分了轨道。 用于这种积分所需的势能也是通过假设不同的引力模型，以数值方式获得的。 我们发现，由于场方程中存在质量项，该理论可以分配新的轨道类别，这些类别在牛顿引力和标准MOND中都不存在。 我们讨论了这些新轨道家族在非线性宇宙结构形成中的潜在影响，同时也探索了基于它们的星系结构替代模型的可能性。 显示英文摘要

摘要： Detailed knowledge of the different classes of stellar orbits that can be accommodated in a given galactic potential is a prerequisite when building self-consistent models using for instance the Schwazschild technique. Furthermore, observational properties of galaxies depend on what these classes of orbits are and on the presence of chaos in the systems. In the realistic case in which the starting point for modeling is not a gravitational potential, but an observed density distribution, we will require a gravitational theory to make the connection between the stars that we see and the movement these stars may be having. The argument can be turned upside down: understanding what orbits may be allowed by each gravitational theory may give us a greater insight on what these theories are and on how we can test them. Our aim is thus to understand novel properties of orbits that are predicted by the latest extension of the MOND phenomenology into the relativistic world. We integrated orbits numerically in a fixed density distribution. The potential required for such integration was obtained also numerically by assuming different gravitational models. We find that thanks to the presence of a mass term in the field equations, the theory can allocate new classes of orbits that do not exist in Newtonian gravity nor standard MOND. We discuss consequences that these new families of orbits can have in non-linear cosmological structure formation as well as explore a possible alternative model for galactic structure based on them.