Leinweber Center for Theoretical Physics, Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
PRISMA Cluster of Excellence and Mainz Institute for Theoretical Physics, Johannes Gutenberg University, 55099 Mainz, Germany.
Phys Rev Lett. 2018 May 25;120(21):211101. doi: 10.1103/PhysRevLett.120.211101.
We propose a novel method utilizing stellar kinematic data to detect low-mass substructure in the Milky Way's dark matter halo. By probing characteristic wakes that a passing dark matter subhalo leaves in the phase-space distribution of ambient halo stars, we estimate sensitivities down to subhalo masses of ∼10^{7} M_{⊙} or below. The detection of such subhalos would have implications for dark matter and cosmological models that predict modifications to the halo-mass function at low halo masses. We develop an analytic formalism for describing the perturbed stellar phase-space distributions, and we demonstrate through idealized simulations the ability to detect subhalos using the phase-space model and a likelihood framework. Our method complements existing methods for low-mass subhalo searches, such as searches for gaps in stellar streams, in that we can localize the positions and velocities of the subhalos today.
我们提出了一种利用恒星运动学数据来探测银河系暗物质晕中低质量亚结构的新方法。通过探测过境暗物质亚结构在周围晕星的相空间分布中留下的特征尾流，我们可以估计出灵敏度低至约 10^{7} M_{⊙}或以下的亚结构质量。这种亚结构的探测将对暗物质和宇宙学模型产生影响，这些模型预测在低晕质量下对晕质量函数进行修正。我们开发了一种分析公式来描述受扰动的恒星相空间分布，并通过理想模拟演示了使用相空间模型和似然框架检测亚结构的能力。我们的方法补充了现有的低质量亚结构搜索方法，例如对恒星流中间隙的搜索，因为我们可以定位亚结构今天的位置和速度。
