大质量黑洞宽窄光学-紫外发射线的统一建模：解读高红移JWST观测
Unified modelling of broad and narrow optical-UV emission lines from massive black holes: interpreting high-redshift JWST observations
- Ecole Polytechnique Federale de Lausanne（洛桑联邦理工学院）
- University of Hertfordshire（赫特福德大学）
- INAF-Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）
- Sorbonne Université, CNRS, UMR7095, Institut d’Astrophysique de Paris（索邦大学，法国国家科学研究中心，巴黎天体物理研究所）
- The University of Texas at Austin（德克萨斯大学奥斯汀分校）
- INAF – Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）
- ESA/AURA Space Telescope Science Institute（欧洲空间局/美国大学研究协会太空望远镜科学研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出统一宽窄线光致电离模型，覆盖亚至超爱丁顿吸积，用于解读JWST高红移AGN观测，发现低质量黑洞可探测下限及稳健示踪线，并指出NLR线比率主要受金属丰度影响。
AI中文摘要：
JWST正在发现大量高红移活动星系核（AGN），这促使我们将基于本地源校准的模型扩展到更广泛的物理条件范围。我们提出了一套一致的宽线和窄线光致电离模型，基于随黑洞质量和爱丁顿比率变化的电离光谱，覆盖从亚爱丁顿到超爱丁顿吸积。对于宽线区（BLR），我们研究了低质量吸积黑洞的可探测性。在z=6时，在有利假设下，对于以爱丁顿极限吸积的黑洞，宽Hα可能可探测到$M_{BH}\approx10^{5.7} M\odot$。我们推导了线光度与吸积光度之间的修正关系，发现氢和氦复合线比金属线提供更稳健的示踪。我们还探讨了黑洞性质和BLR条件的哪些变化可能导致在一些高红移源中观测到的大Hα等值宽度、升高的巴耳末递减和弱高电离线，发现BLR结构的变化可以显著改变发射光谱。对于窄线区（NLR），Hα和[O III] λ5007是低质量吸积黑洞最有前景的示踪之一，在爱丁顿极限下可探测到$M_{BH}\approx10^{5.5} M\odot$。许多经典诊断图遗漏了低金属丰度AGN；我们确定了替代的紫外和光学诊断，在所探索的条件下能更稳健地将AGN与Pop. II和Pop. III恒星光致电离区分开来。然而，NLR线比率主要由金属丰度和电离参数驱动，对黑洞质量和爱丁顿比率的依赖性较弱。展望未来，这些模型旨在用于JWST光谱的贝叶斯解释，并通过物理动机的先验与宇宙学模拟相连接。
英文摘要：
JWST is uncovering a large population of active galactic nuclei (AGN) at high redshift, motivating the extension of models calibrated on local sources to a broader range of physical conditions. We present a consistent suite of broad- and narrow-line photoionisation models based on ionising spectra that vary with black-hole mass and Eddington ratio, spanning sub- to super-Eddington accretion. For the broad-line region (BLR), we investigate the detectability of low-mass accreting black holes. At z=6, broad Hα may be detectable down to $M_{BH}\approx10^{5.7} M\odot$ for a BH accreting at the Eddington limit under favourable assumptions. We derive line-to-accretion-luminosity corrections, with hydrogen and helium recombination lines providing more robust tracers than metal lines. We also explore which changes in black-hole properties and BLR conditions can contribute to the large Hα equivalent widths, elevated Balmer decrements, and weak high-ionisation lines observed in some high-redshift sources, finding that variations in BLR structure can substantially modify the emergent spectrum. For the narrow-line region (NLR), Hα and [O III] λ5007 are among the most promising tracers of low-mass accreting black holes, probing $M_{BH}\approx10^{5.5} M\odot$ at the Eddington limit. Many classical diagnostic diagrams miss low-metallicity AGN; we identify alternative UV and optical diagnostics that more robustly separate AGN from Pop. II and Pop. III stellar photoionisation over the conditions explored. Nevertheless, NLR line ratios are driven primarily by metallicity and ionisation parameter, with only a weak dependence on black-hole mass and Eddington ratio. Looking ahead, these models are intended for Bayesian interpretation of JWST spectra and connection to cosmological simulations through physically motivated priors.
