The bolometric quasar luminosity function at z = 0–7
The bolometric quasar luminosity function at z = 0–7
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DOI：
10.1093/mnras/staa1381
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发表时间：
2020-01
影响因子：
4.8
通讯作者：
Xuejian Shen;P. Hopkins;C. Faucher-Giguère;D. Alexander;G. Richards;N. Ross;R. Hickox
中科院分区：
文献类型：
--
作者：
Xuejian Shen;P. Hopkins;C. Faucher-Giguère;D. Alexander;G. Richards;N. Ross;R. Hickox
在本文中，我们提供了从 z = 0 到 z = 7 的辐射热类星体光度函数 (QLF) 的更新约束。这些约束基于观测汇编，其中包括过去几十年在静止帧红外、B 波段、紫外、软和硬 X 射线中的观测。我们的方法遵循霍普金斯等人的方法。具有更新的类星体 SED 模型以及辐射热和消光校正。新的最佳拟合辐射热类星体光度函数在高红移情况下的表现与旧的霍普金斯模型有本质上的不同。与旧模型相比，数密度归一化向更高的红移方向减小，并且在 z ≳ 2 处亮端斜率更陡。由于暗端测量的缺乏，z ≳ 5 处的暗端斜率相当不确定。我们提出了两种模型，一种在较高红移处具有逐渐陡峭的微端斜率，另一种在 z ≳ 5 处具有浅微端斜率。需要对微端 QLF 进行进一步的多波段观测来区分这些模型。辐射热 QLF 的演化模式可以解释为早期阶段可能以结构的分层组装为主，晚期阶段可能以星系的猝灭为主。我们探讨了该模型对类星体电离光子产生、CXB 光谱、SMBH 质量密度和质量函数的影响。预测的类星体贡献的氢光电离率在再电离时期处于次主导地位，并且仅在 z ≲ 3 时变得重要。预测的 CXB 谱、宇宙 SMBH 质量密度和 SMBH 质量函数与现有观测结果基本一致。
In this paper, we provide updated constraints on the bolometric quasar luminosity function (QLF) from z = 0 to z = 7. The constraints are based on an observational compilation that includes observations in the rest-frame IR, B band, UV, soft, and hard X-ray in past decades. Our method follows Hopkins et al. with an updated quasar SED model and bolometric and extinction corrections. The new best-fitting bolometric quasar luminosity function behaves qualitatively different from the old Hopkins model at high redshift. Compared with the old model, the number density normalization decreases towards higher redshift and the bright-end slope is steeper at z ≳ 2. Due to the paucity of measurements at the faint end, the faint end slope at z ≳ 5 is quite uncertain. We present two models, one featuring a progressively steeper faint-end slope at higher redshift and the other featuring a shallow faint-end slope at z ≳ 5. Further multiband observations of the faint-end QLF are needed to distinguish between these models. The evolutionary pattern of the bolometric QLF can be interpreted as an early phase likely dominated by the hierarchical assembly of structures and a late phase likely dominated by the quenching of galaxies. We explore the implications of this model on the ionizing photon production by quasars, the CXB spectrum, the SMBH mass density, and mass functions. The predicted hydrogen photoionization rate contributed by quasars is subdominant during the epoch of reionization and only becomes important at z ≲ 3. The predicted CXB spectrum, cosmic SMBH mass density, and SMBH mass function are generally consistent with existing observations.