AI 中文总结
该研究针对低质量星系活动探测的灵敏度问题，构建六参数累积吸收截面模型，结合星系恒星质量函数预测z≥5的Si IV柱密度分布，揭示不同质量星系与Si IV吸收体的关联，为相关观测提供理论框架。
AI 中文摘要
即便在JWST时代，直接限制低质量星系活动的努力仍面临灵敏度极限。金属吸收体提供了一种互补探针，且更易被探测，但要利用它们需明确吸收体强度与宿主质量的关系。为此，许多研究假设吸收体强度与宿主质量间存在简单单调关系，这一设想忽略了固定光度星系所拥有的吸收体强度存在多种变化的证据。我们通过从宇宙学模拟中推导六参数累积吸收截面模型来解决此问题，该模型与星系恒星质量函数结合，可预测吸收体柱密度分布（CDD）。最大似然分析证实，此方法能协调观测到的星系恒星质量函数与z=5-6处观测到的Si IV CDD。外推的CDD在观测范围外变得不确定，且所得约束包含简并性，凸显了改进测量的必要性。所有质量的星系都拥有各种强度的吸收体，但研究表明大质量星系与强吸收体间存在微弱的经验关联。暗弱星系（M*<10^8 M☉）拥有大部分弱Si IV吸收体（log N<13），这凸显了发射/吸收体互补性。吸收体几何截面与宿主星系质量间为幂律关系的假设在经验上不受支持。若星系恒星质量函数得到良好约束，该模型可应用于任意离子与红移的组合。未来结合改进的宿主统计数据的观测测试将扩展该模型的适用范围。
英文摘要
Efforts to constrain directly the activity in low-mass galaxies confront sensitivity limits even in the JWST era. Metal absorbers offer a complementary probe and are easier to detect, but leveraging them requires a known relationship between absorber strength and host mass. To this end, many studies assume a simple monotonic relationship between absorber strength and host mass. This ansatz ignores evidence that galaxies at fixed luminosity host absorbers spanning a variety of strengths. We address this issue by deriving a six-parameter model for the cumulative absorption cross section from cosmological simulations that combines with the galaxy stellar mass function to predict the absorber column density distribution (CDD). A maximum-likelihood analysis confirms that this approach reconciles the observed galaxy stellar mass function with the observed SiIV CDD at z=5-6. The extrapolated CDD grows uncertain outside the observed range and the resulting constraints contain degeneracies, highlighting the need for improved measurements. Galaxies of all masses host absorbers of all strengths, but a weak empirical association between massive galaxies and strong absorbers is indicated. Faint galaxies (M* < 10^8 Msun) host the majority of weak SiIV absorbers (log N < 13), emphasizing emission/absorber complementarity. The assumption of a power-law relationship between absorbers' geometric cross sections and host galaxy masses is empirically disfavored. The model may be applied to any combination of ion and redshift if the galaxy stellar mass function is well-constrained. Future observational tests incorporating improved host statistics will extend the model's range.
Comments22 Pages, 14 figures, accepted to ApJ, where the definitive version is available
