论文标题
从Lyman- $α$森林功率谱系中对温暖暗物质的新约束
New Constraints on Warm Dark Matter from the Lyman-$α$ Forest Power Spectrum
论文作者
论文摘要
在遥远的类星体的光谱中检测到的Lyman-$α$吸收线的森林编码有关暗物质的性质和特性的信息以及弥漫性重质材料的热力学。与标准的$λ$ CDM相比，它的主要可观察到的可观察到的1D通量功率谱（FPS）应在小尺度上表现出抑制作用，并在温暖的暗物质（WDM）宇宙中表现出大尺度的增强功能。在这里，我们提供了一个前所未有的套件，其中包括图形处理单元加速的代码CHOLLA进行的1080个高分辨率宇宙流体动力学模拟，以研究Lyman- $α$森林的演变，这些林中的演变在广泛的物理动力的气体热历史中，以及不同的自由流式的WDM Thermal Thermal Proferal Isse norkics of the Errical oferics of the word formoral of the Errical oferics。 A statistical comparison of synthetic data with the forest FPS measured down to the smallest velocity scales ever probed at redshifts $4.0\lesssim z\lesssim 5.2$ (Boera et al. 2019) yields a lower limit $m_{\rm WDM}>3.1$ keV (95 percent CL) for the WDM particle mass and constrains the amplitude and spectrum of the photoheating以及在这些红移处由星形星系和活性银河核产生的光电离心背景。有趣的是，我们的贝叶斯推理分析似乎微弱地偏爱WDM模型，其热液体质量为$ M _ {\ rm WDM} = 4.5 $ keV。 We find that the suppression of the FPS from free-streaming saturates at $k\gtrsim 0.1\,\mathrm{s}\,\mathrm{km}^{-1}$ because of peculiar velocity smearing, and this saturated suppression combined with a slightly lower gas temperature provides a moderately better fit to the observed small-scale FPS for WDM cosmologies.
The forest of Lyman-$α$ absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic material. Its main observable -- the 1D flux power spectrum (FPS) -- should exhibit a suppression on small scales and an enhancement on large scales in warm dark matter (WDM) cosmologies compared to standard $Λ$CDM. Here, we present an unprecedented suite of 1080 high-resolution cosmological hydrodynamical simulations run with the Graphics Processing Unit-accelerated code Cholla to study the evolution of the Lyman-$α$ forest under a wide range of physically-motivated gas thermal histories along with different free-streaming lengths of WDM thermal relics in the early Universe. A statistical comparison of synthetic data with the forest FPS measured down to the smallest velocity scales ever probed at redshifts $4.0\lesssim z\lesssim 5.2$ (Boera et al. 2019) yields a lower limit $m_{\rm WDM}>3.1$ keV (95 percent CL) for the WDM particle mass and constrains the amplitude and spectrum of the photoheating and photoionizing background produced by star-forming galaxies and active galactic nuclei at these redshifts. Interestingly, our Bayesian inference analysis appears to weakly favor WDM models with a peak likelihood value at the thermal relic mass of $m_{\rm WDM}=4.5$ keV. We find that the suppression of the FPS from free-streaming saturates at $k\gtrsim 0.1\,\mathrm{s}\,\mathrm{km}^{-1}$ because of peculiar velocity smearing, and this saturated suppression combined with a slightly lower gas temperature provides a moderately better fit to the observed small-scale FPS for WDM cosmologies.
