增强的密度涨落：对恒星动力学和暗物质子结构的影响
Enhanced density fluctuations: consequences for stellar dynamics and dark matter substructure
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中文总结 AI 辅助
该研究探讨增强密度涨落对早期天体形成及暗物质子结构的影响，发现其可显著增加银河系捕获星团数量及大质量暗物质子晕丰度，并提高可探测性。
中文摘要 AI 辅助
增强的密度涨落会形成早期暗物质晕，这些暗物质晕充当重子物质的早期引力势阱。重子物质随后可以在高红移（$1+z \gtrsim 100$）下凝聚形成恒星和黑洞。更大的密度涨落导致更致密、具有更高维里温度的暗物质晕；因此，一个质量低于标准天体物理预期下恒星形成阈值的光晕，如果其初始密度高于预期，则可能形成天体物理天体，尽管致密天体形成的确切阈值受到很大的天体物理不确定性的影响。我们概述了增强的密度涨落形成暗（无恒星）光晕、早期星系甚至星团的条件。利用已被证明可以解释“小红点”丰度的原初功率谱的玩具模型增强，以及我们的一组基准天体物理参数，我们表明银河系最初捕获的星团数量对增强的形状高度敏感，窄峰增强导致50个星团，而阶跃函数增强导致约$4.1 \times 10^5$个星团。星团的初始恒星质量也在$O(100)\\,M_\odot$量级，尽管这一范围也取决于增强的形状。此外，质量大于$10^7\\,M_\odot$的暗物质子晕的丰度可以被增强多达约6.5倍，并且比$\Lambda$CDM模型中的更致密，这将提高它们在未来的恒星流巡天（如Via项目）中的可探测性。
英文摘要
Enhanced density fluctuations form early dark matter halos, which serve as early gravitational potential wells for baryons. These baryons can then condense to form stars and black holes at high redshifts, $1+z \gtrsim 100$. Larger density fluctuations result in denser halos with higher virial temperatures; hence, a halo at a mass that is below the threshold for forming stars under standard astrophysical expectations may form astrophysical objects if its initial density is higher than expected, although the exact threshold for compact object formation is subject to large astrophysical uncertainties. We outline the conditions under which enhanced density fluctuations form dark (star-less) halos, early galaxies, or even star clusters. Using toy model enhancements to the primordial power spectrum that have been shown to explain the abundances of ``little red dots", along with our fiducial set of astrophysical parameters, we show that the number of clusters initially captured by the Milky Way is highly sensitive to the shape of the enhancement, with the narrowly peaked enhancement resulting in $50$ clusters and the step-function enhancement resulting in $\sim 4.1 \times 10^5$. The initial stellar masses of the clusters is also $O (100) \,M_\odot$, although this range is also dependent on the shape of the enhancement. In addition, the abundance of dark matter subhalos with masses greater than $10^7 \, M_\odot$ can be enhanced by as much as a factor of $\sim 6.5$ and is denser than in $Λ$CDM, which will increase their detectability in future stellar stream surveys such as the Via Project.
发表机构
- New York University（纽约大学）
- Johns Hopkins University（约翰斯·霍普金斯大学）
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