AI 中文总结
研究高红移类星体对应的重黑洞种子形成机制，通过65套宇宙学模拟提出估算第三星族星质量的方法，发现中等莱曼-沃纳背景下重黑洞种子形成环境更普遍。
AI 中文摘要
高红移类星体的存在可能表明，大质量黑洞种子由原子冷却晕中超大质量第三星族星形成，这类晕具有极高的气体吸积率；然而，该过程对晕并合率和辐射背景的依赖关系仍未得到很好的约束。我们针对15个原始晕开展了共65套高分辨率宇宙学 zoom-in 模拟，覆盖宽范围的莱曼-沃纳辐射背景和晕并合历史。我们提出一种新方法，可从坍缩失控起始阶段的径向气体下落轮廓估算最终第三星族星质量，并通过与文献中采用 sink 粒子追踪原恒星吸积的模拟进行对比验证，该方法对原恒星质量的估算误差在约2倍以内。我们发现，当晕暴露于J₂₁≤1和J₂₁≥10时，气体下落率存在明显转变；后者常能维持高于超大质量恒星形成阈值的吸积率，估算恒星质量最高达10⁵M☉。相比之下，尽管晕并合率跨度为0.01-7M☉/年，但晕并合时标M_Halo/Ṁ_Halo与预测恒星质量无统计显著相关性。因此，在我们的参数空间内，莱曼-沃纳辐射场是维持高吸积的更强预测因子。最后，将半解析模型应用于宇宙学体积显示，暴露于中等莱曼-沃纳背景（1≤J₂₁<10）的晕数量比高J₂₁尾部的晕多几个数量级。若高吸积能延伸至该中等区域，重黑洞种子形成的环境将比经典直接坍缩场景所需的环境普遍得多。
英文摘要
The existence of high-redshift quasars may indicate that massive black hole seeds formed via supermassive Population III stars in atomic-cooling halos with large gas inflow rates; however, the dependence of this process on halo assembly rate and radiative background remains poorly constrained. We present a large suite of 65 high-resolution cosmological zoom-in simulations of 15 pristine halos spanning a wide range of Lyman-Werner radiation backgrounds and halo assembly histories. We introduce a novel method to estimate the final Population III stellar mass from radial gas infall profiles at the onset of runaway collapse and validate it against simulations from the literature that explicitly follow protostellar accretion with sink particles, reproducing protostellar masses to within a factor of $\sim2$. We find a clear transition in gas inflow rates between halos exposed to $J_{\rm 21} \lesssim 1$ and $J_{\rm 21} \gtrsim 10$, with the latter frequently sustaining inflow rates above the adopted threshold for supermassive star formation and producing estimated stellar masses up to $10^{5} \, M_{\odot}$. In contrast, the halo assembly timescale, $M_{\rm Halo}$/$\dot{M}_{\rm Halo}$, shows no statistically significant correlation with predicted stellar mass, despite halo assembly rates spanning $0.01$-$7 \, M_{\rm \odot} \, {\rm yr}^{-1}$. The Lyman-Werner radiation field therefore is a stronger predictor of sustained high accretion within our parameter space. Finally, a semi-analytic model applied to cosmological volumes shows that halos exposed to intermediate Lyman-Werner backgrounds ($1 \lesssim J_{\rm 21} < 10$) are orders of magnitude more common than those in the high-$J_{\rm 21}$ tail. If sustained high accretion extends into this intermediate regime, heavy black hole seeds may form in substantially more common environments than required by classical direct-collapse scenarios.
Comments31 pages, 10 figures, submitted to JCAP
