发表机构
Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University; School of Physics and Astronomy, Beijing Normal University; National Astronomical Observatories, Chinese Academy of Sciences; School of Accountancy, Central University of Finance and Economics; School of Physics and Astronomy, Anqing Normal University（北京师范大学前沿天体物理研究所; 北京师范大学物理与天文学院; 中国科学院国家天文台; 中央财经大学会计学院; 安庆师范大学物理与天文学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究探讨利用纤维状21厘米辐射区分冷暗物质与温暗物质模型的可能性，发现现有及规划中的SKA-Low设备无法实现这一目标。
AI 中文摘要
宇宙网包含了宇宙中的大部分物质，其纤维状结构与暗物质的性质密切相关。与冷暗物质（CDM）模型相比，温暗物质（WDM）会抑制低质量暗晕的形成，产生更平滑的宇宙纤维。本研究探讨在红移z=4和z=2.5时，能否利用纤维状21厘米辐射区分这两种暗物质模型。研究人员通过宇宙流体动力学模拟生成本征21厘米亮温度图，再将其与不同角分辨率的高斯波束卷积生成模拟观测数据，随后将预测的纤维信号与SKA1-Low和规划中的SKA2-Low的预期灵敏度进行比较。研究发现，本征21厘米辐射清晰反映了CDM和WDM模型中不同的纤维形态，尤其是在z=4时；但随着波束尺寸增大，这些差异会迅速消失，尤其是波束尺寸大于6角秒时。尽管更大的波束能提升观测灵敏度，但也会抹去编码暗物质信息的小尺度结构。因此，SKA1-Low和规划中的SKA2-Low都无法以足够的灵敏度直接分辨单个纤维来区分两种暗物质模型，研究得出结论：利用现有及规划中的SKA-Low设备对宇宙纤维进行直接成像并通过其形态约束暗物质，不太可能可行。
英文摘要
The cosmic web contains most of the matter in the Universe, and its filamentary structure is closely related to the properties of dark matter. Compared with the cold dark matter (CDM) model, warm dark matter (WDM) suppresses the formation of low-mass halos and produces smoother cosmic filaments. In this work, we explore whether filamentary 21cm emission can be used to distinguish between these two dark matter models at $z=4$ and $2.5$. We generate intrinsic 21cm brightness temperature maps from cosmological hydrodynamical simulations and produce mock observations by convolving them with Gaussian beams of different angular resolutions. We then compare the predicted filament signals with the expected sensitivities of SKA1-Low and SKA2-Low. We find that the intrinsic 21cm emission clearly reflects the different filament morphologies in the CDM and WDM models, particularly at $z=4$. However, these differences rapidly disappear as the beam size increases, especially for beam sizes larger than 6 arcsec. Although larger beams improve the observational sensitivity, they also erase the small-scale structures that encode the dark matter information. As a result, neither SKA1-Low nor the planned SKA2-Low can directly resolve individual filaments with sufficient sensitivity to distinguish between the two models. We therefore conclude that direct imaging of cosmic filaments and constraining dark matter through their morphology are unlikely to be feasible with current and planned SKA-Low facilities.
Comments12 pages, 4 figures, accepted for publication in Research in Astronomy and Astrophysics
