标题： 冷暗物质和热暗物质向宇宙弦纤维的吸积 显示英文标题

标题： Accretion of Cold and Hot Dark Matter onto Cosmic String Filaments

摘要： 泽尔多维奇近似被应用于研究热暗物质和冷暗物质在移动长弦上的吸积现象。假设这些缺陷携带大量的小尺度结构，从而在引力作用下表现为牛顿线源，其效应主导了速度扰动。推导出了回转表面的解析表达式，并计算了这些表面上内部的质量。给出了参数 $\Omega_{nl}$（即非线性物体中质量占比）随红移变化的估计值。根据参数的不同，目前有可能获得 $\Omega_{nl} = 1$。即使有热暗物质的存在，在接近红移100时，第一个非线性丝状结构也会形成，并且有足够的非线性质量来解释高红移类星体和强阻尼氢吸收线系统的观测丰度。这些结果表明，带有小尺度结构的移动弦是最有效的种子，可以在宇宙弦模型中产生大质量的非线性天体。 显示英文摘要

摘要： The Zeldovich approximation is applied to study the accretion of hot and cold dark matter onto moving long strings. It is assumed that such defects carry a substantial amount of small-scale structure, thereby acting gravitationally as a Newtonian line source whose effects dominate the velocity perturbations. Analytical expressions for the turn-around surfaces are derived and the mass inside of these surfaces is calculated. Estimates are given for the redshift dependence of $\Omega_{nl}$, the fraction of mass in nonlinear objects. Depending on parameters, it is possible to obtain $\Omega_{nl} = 1$ at the present time. Even with hot dark matter, the first nonlinear filamentary structures form at a redshift close to 100, and there is sufficient nonlinear mass to explain the observed abundance of high redshift quasars and damped Lyman alpha systems. These results imply that moving strings with small-scale structure are the most efficient seeds to produce massive nonlinear objects in the cosmic string model.