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The Bolometric Quasar Luminosity Function at z = 0 − 7

Hickox, R.C.; Ross, Nicholas P.; Richards, Gordon T.; Alexander, D.M.; Faucher-Giguère, Claude-André; Hopkins, Philip F.; Shen, Xuejian

The Bolometric Quasar Luminosity Function at z = 0 − 7 Thumbnail


R.C. Hickox

Nicholas P. Ross

Gordon T. Richards

Claude-André Faucher-Giguère

Philip F. Hopkins

Xuejian Shen


In this paper, we provide updated constraints on the bolometric quasar luminosity function (QLF) from 푧 = 0 to 푧 = 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. 2007 with an updated quasar SED model and bolometric and extinction corrections. The new best-fit bolometric quasar luminosity function behaves qualitatively different from the Hopkins et al. 2007 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 푧 & 2. Due to the paucity of measurements at the faint end, the faint end slope at 푧 & 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 푧 & 5. Further multi-band 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 푧 . 3. The predicted CXB spectrum, cosmic SMBH mass density and SMBH mass function are generally consistent with existing observations.


Hickox, R., Ross, N. P., Richards, G. T., Alexander, D., Faucher-Giguère, C., Hopkins, P. F., & Shen, X. (2020). The Bolometric Quasar Luminosity Function at z = 0 − 7. Monthly Notices of the Royal Astronomical Society, 495(3), 3252-3275.

Journal Article Type Article
Acceptance Date May 8, 2020
Online Publication Date May 20, 2020
Publication Date Jul 1, 2020
Deposit Date May 21, 2020
Publicly Available Date May 22, 2020
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 495
Issue 3
Pages 3252-3275
Public URL


Accepted Journal Article (2.3 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s) . Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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