测试折射引力与堆叠星系团运动学
Testing Refracted Gravity with the kinematics of stacked galaxy clusters
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中文总结 AI 辅助
本研究通过堆叠星系团运动学测试折射引力模型，利用MG-MAMPOSSt代码推断参数，发现真空介电常数约束与先前结果兼容，并揭示其对重子建模和样本选择的敏感性。
中文摘要 AI 辅助
我们测试了折射引力（RG），这是一种现象学修正引力模型，通过引入依赖于重子物质密度 $\rho_{\rm bar}$ 的有效引力介电常数 $\epsilon(\rho_{\rm bar})$ 来修正泊松方程，并模拟宇宙结构中暗物质的行为。我们对从斯隆数字巡天（SDSS）的星系团内落区（CIRS）汇编的74个星系团样本中的成员星系进行了运动学分析。我们将星系团按递增的速度弥散分为三个堆叠区间，以减轻由偏离动力学平衡和球对称假设引起的系统误差的影响。利用 \texttt{MG-MAMPOSSt} 代码，我们在RG中重建引力势，并联合推断模型参数与气体和恒星质量轮廓参数，对重子成分采用宽泛且物理信息丰富的先验。折射引力中主要参数——真空介电常数 $\epsilon_0$ 的估计值，在三个主要堆叠中，根据所采用的热气体成分模型，范围从0.04到0.37。这些约束在所述不确定度内相互兼容，并与先前的星系团尺度估计重叠。当选择扰动较小的星系团构建堆叠时，一致性对气体参数化的敏感度降低。这些结果表征了星系团尺度RG约束对重子建模和样本选择的敏感性。
英文摘要
We test Refracted Gravity (RG), a phenomenological modified gravity model that modifies the Poisson equation by introducing an effective gravitational permittivity $ε(ρ_{\rm bar})$ which depends on the baryonic matter density $ρ_{\rm bar}$ and mimics the behaviour of dark matter in cosmic structures. We perform a kinematical analysis of member galaxies for a sample of 74 galaxy clusters, compiled from the Cluster Infall Regions in the Sloan Digital Sky Survey (CIRS). We stack the clusters in three bins of increasing velocity dispersion to mitigate the effects of systematic errors induced by deviations from dynamical equilibrium and from the assumption of spherical symmetry. By means of the \texttt{MG-MAMPOSSt} code, we reconstruct the gravitational potential in RG and infer the model parameters jointly with the gas and stellar mass-profile parameters, adopting broad, physically informed priors on the baryonic components. The estimates of the main parameter in Refracted Gravity, the vacuum permittivity $ε_0$, range from $0.04$ to $0.37$, across the three main stacks, depending on the model adopted for the hot gas component. The constraints are mutually compatible within the quoted uncertainties and overlap with previous cluster-scale estimates. The agreement becomes less sensitive to gas parametrisation when selecting the less-disturbed clusters for building the stacks. These results characterize the sensitivity of cluster-scale RG constraints to baryonic modelling and sample selection
发表机构
- Università degli Studi di Milano-Bicocca（米兰比可卡大学）
- Università di Torino（都灵大学）
- Istituto Nazionale di Fisica Nucleare, sezione di Torino（意大利国家核物理研究所都灵分部）
- Accademia delle Scienze di Torino（都灵科学院）
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