基于盘的IllustrisTNG50中局部暗物质密度与速度分布的估计
Disc-Based Estimation of the Local Dark Matter Density and Velocity Distribution in IllustrisTNG50
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中文总结 AI 辅助
研究利用IllustrisTNG50模拟，通过盘提取法确定类银河系星系太阳邻域的局部暗物质密度与速度分布，其结果与观测及标准模型吻合，且对直接探测实验影响不大。
中文摘要 AI 辅助
我们利用IllustrisTNG模拟套件的TNG50-1运行结果，研究类银河系星系太阳邻域的暗物质（DM）密度与速度分布。根据晕质量和恒星质量的核球占比筛选类银河系星系，通过恒星的位置和数密度确定每个星系的太阳邻域区域，从而提取与星系盘相关的DM粒子，同时抑制晕成分的贡献。对筛选出的星系取平均，得到局部DM密度为ρ≈0.47±0.02 GeV·cm⁻³，与观测推断的范围一致。基于盘的提取得到的峰值密度为0.41±0.02 GeV·cm⁻³，高于简单距离提取的0.34±0.02 GeV·cm⁻³，这可能是因为排除了晕中的低密度DM；而密度分布的宽度几乎未变。速度分布可由各向同性麦克斯韦分布很好地描述，峰值速度约为226 km·s⁻¹，接近标准晕模型中假设的值。基于盘的提取与简单距离提取得到的密度和速度分布差异，未大到足以显著影响直接探测实验的解释。
英文摘要
We study the dark matter (DM) density and velocity distribution in the solar neighborhood of Milky Way-like galaxies using the TNG50-1 run of the IllustrisTNG simulation suite. Milky Way-like galaxies are selected according to both their halo mass and their bulge-to-total stellar mass ratio, and the solar-neighborhood region within each galaxy is identified from the positions and number density of stars, so that DM particles associated with the galactic disc are extracted while contributions from the halo component are suppressed. Averaging over the selected galaxies, we obtain a local DM density of $ρ\simeq 0.47\pm0.02~{\rm GeV\,cm^{-3}}$, consistent with the range inferred from observations. The disc-based extraction gives a higher peak density, $0.41\pm0.02~{\rm GeV\,cm^{-3}}$, than the value $0.34\pm0.02~{\rm GeV\,cm^{-3}}$ from a simple distance-based extraction, probably because it excludes the low-density DM in the halo. The width of the density distribution, on the other hand, is nearly unchanged. The velocity distribution is well described by an isotropic Maxwellian with a peak velocity of about $226~{\rm km~s^{-1}}$, close to the value assumed in the standard halo model. The differences in the density and velocity distributions between our disc-based and simple distance-based extractions are not so large as to significantly affect the interpretation of direct-detection experiments.
发表机构
- Okayama University of Science（冈山科学大学）
- Chukyo University（中京大学）
- Nagoya University（名古屋大学）
- SOKENDAI（日本综合研究大学院大学）
机构由 AI 辅助整理，请以论文原文为准。
