论文标题
银河系间培养基对电离的流体动力反应
Hydrodynamic Response of the Intergalactic Medium to Reionization
论文作者
论文摘要
预计层间培养基将在降低到$ 10^4-10^8 $ m $ _ {\ odot} $之前，将其降低到$ 10^4-10^8 $ M $ _ {\ odot} $。尽管现代的理解，气体块限制了H II区域的生长，但这些小规模结构对电源的影响尚不清楚。我们使用一套放射线式动力学模拟，以捕获$ \ sim 10^4 $ $ $ $ $ $ $ $ $ $ $ odot $牛仔裤质量未加热的气体，以研究在恢复过程中的密度波动。我们的仿真跟踪电离界面后气体的复杂电离和流体动力响应。电离气体的结块因子（与重组速率成正比）上升到$ 5-20 $Δt= 10 $ MYR $ 5-20 $ΔT= 10 $ MYR，这取决于入射强度，红移和该气体已通过第一个X射线源预先加热的气体的程度。结块因子的放松价值约为$ \ 3 $ x $ΔT= 300 $ MYR。 Lyman-limit光子的平均自由路径一致演变，与更早的离子进行了相比，在未省力的，最近恢复的区域中的平均自由路径短几倍。在评估这种反应对全球reionizaton过程的影响时，我们发现未放松的气态结构将重组总数增加了$ \ \ \ \ \ \ \ 50 $％，并导致平均自由路径的空间波动，这些路径是在平均自由路径中持续持续数亿年后的数百万年后，重新组装了数亿年。
The intergalactic medium is expected to clump on scales down to $10^4-10^8$ M$_{\odot}$ before the onset of reionization. The impact of these small-scale structures on reionization is poorly understood despite the modern understanding that gas clumpiness limits the growth of H II regions. We use a suite of radiation-hydrodynamics simulations that capture the $\sim 10^4$ $M_\odot$ Jeans mass of unheated gas to study density fluctuations during reionization. Our simulations track the complex ionization and hydrodynamical response of gas in the wake of ionization fronts. The clumping factor of ionized gas (proportional to the recombination rate) rises to a peak value of $5-20$ approximately $Δt = 10$ Myr after ionization front passage, depending on the incident intensity, redshift, and degree to which the gas had been pre-heated by the first X-ray sources. The clumping factor reaches its relaxed value of $\approx 3$ by $Δt = 300$ Myr. The mean free path of Lyman-limit photons evolves in unison, being up to several times shorter in un-relaxed, recently reionized regions compared to those that were reionized much earlier. Assessing the impact of this response on the global reionizaton process, we find that un-relaxed gaseous structures boost the total number of recombinations by $\approx 50$ % and lead to spatial fluctuations in the mean free path that persist appreciably for several hundred million years after the completion of reionization.
