论文标题
超扩散星系中的DHOST重力 - 第一部分:NGC1052-DF2案例
DHOST gravity in Ultra-diffuse galaxies -- Part I: the case of NGC1052-DF2
论文作者
论文摘要
Ultra-diffuse Galaxy NGC1052-DF2最近受到了严格的审查,因为从其运动学开始,它在暗物质中揭示了“极度缺陷”,即使根本没有缺少。这一主张提出了有关超湿星系中重子与暗物质之间关系的许多问题和解决方案。但是,似乎有一个相当一致的信念,即如果确认如此低的暗物质含量并将其扩展到其他类似的银河对象,那么它可能是修改和扩展一般相对性的理论的死亡。因此,缺乏暗物质星系代表了测试标准暗物质和修饰的重力理论的肥沃地面。在这项工作中,我们考虑了一个特定的退化标量张量模型来研究与NGC1052-DF2相关的十个紧凑型球状簇样物体的速度分散,以推断银河系的动力学质量。由于相应的筛选机制的部分破裂,该模型可能具有较大的宇宙学量表影响,从而影响了星系等较小结构的动力学。我们考虑两种情况:一个模型仅描述暗能量的情况;它另外一个完全替代了暗物质。我们发现,解释数据的最佳模型是我们具有一般相对论和仅出色贡献的模型。但是,尽管在以前的情况下,一般相对论仍然是统计学上的(贝叶斯),但在后者中,替代模型在匹配观测值中的替代模型与一般相对性一样多。因此,我们可以得出结论,即使像NGC1052-DF2这样的物体也不是对比的,也不是障碍,并且对研究的定义也不是对一般相对性的可靠替代方案的定义。
The Ultra-Diffuse galaxy NGC1052-DF2 has recently been under intense scrutiny because from its kinematics it has revealed to be "extremely deficient" in dark matter, if not lacking it at all. This claim has raised many questions and solutions regarding the relationship between baryons and dark matter in Ultra-Diffuse galaxies. But there seems to be a quite unanimous belief that, if such very low dark matter content is confirmed and extended to other similar galactic objects, it might be a deathblow to theories which modify and extend General Relativity. Deficient dark matter galaxies thus represent a fertile ground to test both standard dark matter and modified gravity theories. In this work, we consider a specific Degenerate Higher-Order Scalar Tensor model to study the velocity dispersion of ten compact globular clusters-like objects associated with NGC1052-DF2 to infer the dynamical mass of the galaxy. Due to the partial breaking of the corresponding screening mechanism, this model can possibly have large cosmological scale effects influencing the dynamics of smaller structures like galaxies. We consider two scenarios: one in which the model only describes dark energy; and one in which it additionally entirely substitutes dark matter. We find that the best model to explain data is the one in which we have General Relativity and only stellar contribution. But while in former scenario General Relativity is still statistically (Bayesian) favoured, in the latter one the alternative model is as much successful and effective as General Relativity in matching observations. Thus, we can conclude that even objects like NGC1052-DF2 are not in contrast, and are not obstacles, to the study and the definition of a reliable alternative to General Relativity.