Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, New Jersey 08544, USA.
Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH, United Kingdom.
Phys Rev Lett. 2019 Oct 4;123(14):141301. doi: 10.1103/PhysRevLett.123.141301.
In hierarchical models of structure formation, the first galaxies form in low-mass dark matter potential wells, probing the behavior of dark matter on kiloparsec scales. Even though these objects are below the detection threshold of current telescopes, future missions will open an observational window into this emergent world. In this Letter, we investigate how the first galaxies are assembled in a "fuzzy" dark matter (FDM) cosmology where dark matter is an ultralight ∼10^{-22} eV boson and the primordial stars are expected to form along dense dark matter filaments. Using a first-of-its-kind cosmological hydrodynamical simulation, we explore the interplay between baryonic physics and unique wavelike features inherent to FDM. In our simulation, the dark matter filaments show coherent interference patterns on the boson de Broglie scale and develop cylindrical solitonlike cores, which are unstable under gravity and collapse into kiloparsec-scale spherical solitons. Features of the dark matter distribution are largely unaffected by the baryonic feedback. On the contrary, the distributions of gas and stars, which do form along the entire filament, exhibit central cores imprinted by dark matter-a smoking gun signature of FDM.
在结构形成的层次模型中，第一代星系在低质量暗物质势阱中形成，探测暗物质在千帕秒尺度上的行为。尽管这些物体低于当前望远镜的探测阈值，但未来的任务将为这个新兴的世界开辟一个观测窗口。在这封信中，我们研究了第一代星系是如何在“模糊”暗物质（FDM）宇宙学中组装的，在这种宇宙学中，暗物质是一种超轻的 ∼10^{-22} eV 玻色子，预计原始恒星将沿着密集的暗物质纤维形成。我们使用一种首创的宇宙流体动力学模拟，探索了重子物理和 FDM 固有的独特波动特征之间的相互作用。在我们的模拟中，暗物质纤维在玻色子德布罗意尺度上显示出相干干涉模式，并形成圆柱状类孤子核，这些核在重力作用下不稳定并塌缩成千帕秒尺度的球形孤子。暗物质分布的特征在很大程度上不受重子反馈的影响。相反，气体和恒星的分布，它们确实沿着整个纤维形成，表现出暗物质印记的中心核心——这是 FDM 的一个明显特征。
