Eddington accreting Black Holes in the Epoch of Reionization

Abstract

The evolution of the luminosity function (LF) of Active Galactic Nuclei (AGNs) at $z\gtrsim 5$ represents a key constraint to understand their contribution to the ionizing photon budget necessary to trigger the last phase transition in the Universe, i.e. the epoch of Reionization. Recent searches for bright high-z AGNs suggest that the space densities of this population at $z>4$ has to be revised upwards, and sparks new questions about their evolutionary paths. Gas accretion is the key physical mechanism to understand both the distribution of luminous sources and the growth of central Super-Massive Black Holes (SMBHs). In this work, we model the high-z AGN-LF assuming that high-z luminous AGN shine at their Eddington limit: we derive the expected evolution as a function of the ``duty-cycle'' ($f_{\mathrm{dc}}$), i.e. the fraction of life-time that a given SMBH spends accreting at the Eddington rate. Our results show that intermediate values ($f_{\mathrm{dc}}\simeq 0.1$) predict the best agreement with the ionizing background and photoionization rate, but do not provide enough ionizing photons to account for the observed evolution of the hydrogen neutral fraction. Smaller values ($f_{\mathrm{dc}}\lesssim 0.05$) are required for AGNs to be the dominant population responsible for Hydrogen reionization in the Early Universe. We then show that this low-$f_{\mathrm{dc}}$ evolution can be reconciled with the current constraints on Helium reionization, although it implies a relatively large number of inactive SMBHs at $z\gtrsim 5$, in tension with SMBH growth models based on heavy seeding.

arXiv comment11 pages, 5 figures, MNRAS accepted

References in corpus (89)

• Planck 2013 results. XVI. Cosmological parameters
• A luminous quasar at a redshift of z = 7.085
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background
• An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
• Observational constraints on growth of massive black holes
• Equation of State of the Photoionized Intergalactic Medium
• Radiative Transfer in a Clumpy Universe: III. The Nature of Cosmological Ionizing Sources
• The Assembly of the First Massive Black Holes
• The Rest-Frame Extreme Ultraviolet Spectral Properties of QSOs
• The Canada-France High-z Quasar Survey: nine new quasars and the luminosity function at redshift 6
• Model-independent evidence in favor of an end to reionization by z~6
• A Luminous Quasar at Redshift 7.642
• Self-Regulated Growth of Supermassive Black Holes in Galaxies as the Origin of the Optical and X-ray Luminosity Functions of Quasars
• Reionization after Planck: The Derived Growth of the Cosmic Ionizing Emissivity now matches the Growth of the Galaxy UV Luminosity Density
• UV Continuum Slope and Dust Obscuration from z~6 to z~2: The Star Formation Rate Density at High Redshift
• The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly$\alpha$ Emission from Galaxies
• Cosmic Reionization after Planck: Could Quasars Do It All?
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• Luminosity functions of Lyman-alpha emitters at z=6.5, and z=5.7: evidence against reionization at z=6
• Implications for the Cosmic Reionization from the Optical Afterglow Spectrum of the Gamma-Ray Burst 050904 at z = 6.3
• The Bolometric Quasar Luminosity Function at z = 0-7
• Faint AGNs at z>4 in the CANDELS GOODS-S field: looking for contributors to the reionization of the Universe
• New Measurements of the Ionizing Ultraviolet Background over 2 < z < 5 and Implications for Hydrogen Reionization
• A synthesis model for AGN evolution: supermassive black holes growth and feedback modes
• Quantitative Constraints on the Reionization History from the IGM Damping Wing Signature in Two Quasars at z > 7
• Formation of the first nuclear clusters and massive black holes at high redshift
• Cold flows and the first quasars
• The Assembly of Supermassive Black Holes at High Redshifts
• Line Emitting Galaxies Beyond a Redshift of 7: An Improved Method for Estimating the Evolving Neutrality of the Intergalactic Medium
• The first ultraviolet quasar stacked spectrum at z=2.4 from WFC3
• Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey
• Hyper-Eddington accretion flows onto massive black holes
• Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). V. Quasar Luminosity Function and Contribution to Cosmic Reionization at z = 6
• Systematic Identification of LAEs for Visible Exploration and Reionization Research Using Subaru HSC (SILVERRUSH). I. Program Strategy and Clustering Properties of ~2,000 Lya Emitters at z=6-7 over the 0.3-0.5 Gpc${}^2$ Survey Area
• Rapid Decline of Lyman-alpha Emission Toward the Reionization Era
• Constraining the neutral fraction of hydrogen in the IGM at redshift 7.5
• Consistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium
• Measurements of the UV background at 4.6 < z < 6.4 using the quasar proximity effect
• Accelerated Evolution of Ly$\alpha$ Luminosity Function at $\text{z}\gtrsim 7$ Revealed by the Subaru Ultra-Deep Survey for Ly$\alpha$ Emitters at $\text{z}=7.3$
• Discovery of the First Low-Luminosity Quasar at z > 7
• Initial mass function of intermediate mass black hole seeds
• The mean free path of ionizing photons at 5 < z < 6: evidence for rapid evolution near reionization
• First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization III. the Ly$\alpha$ Equivalent-width Distribution and Ionized Structures at $z>7$
• Large Fluctuations in the High-Redshift Metagalactic Ionizing Background
• Evidence of Gunn-Peterson damping wings in high-z quasar spectra: strengthening the case for incomplete reionization
• From the first stars to the first black holes
• HST-COS Observations of AGN. II. Extended Survey of Ultraviolet Composite Spectra from 159 Active Galactic Nuclei
• Near-zone sizes and the rest frame extreme ultra-violet spectral index of the highest redshift quasars
• Super-Eddington growth of the first black holes
• Measurements of the z ~ 6 Intergalactic Medium Optical Depth and Transmission Spikes Using a New z > 6.3 Quasar Sample
• Early and Extended Helium Reionization Over More Than 600 Million Years of Cosmic Time
• The Global History of Reionisation
• The Subaru high-z quasar survey: discovery of faint z~6 quasars
• The End of Helium Reionization at z~2.7 Inferred from Cosmic Variance in HST/COS HeII Lyman Alpha Absorption Spectra
• The low-end of the black hole mass function at cosmic dawn
• On the relative Contribution of high-redshift Galaxies and Active Galactic Nuclei to Reionization
• The History and Morphology of Helium Reionization
• IGM damping wing constraints on reionisation from covariance reconstruction of two $z\gtrsim 7$ QSOs
• The Evolution of the Lyman-Alpha Luminosity Function During Reionization
• The contribution of faint AGNs to the ionizing background at z~4
• LAGER Ly$\alpha$ Luminosity Function at $z\sim 7$, Implications for Reionization
• Minor Contribution of Quasars to Ionizing Photon Budget at z~6: Update on Quasar Luminosity Function at the Faint-end with Subaru/Suprime-Cam
• The Spectral Slope and Escape Fraction of Bright Quasars at $z\sim 3.8$: the Contribution to the Cosmic UV Background
• The Rise of Active Galactic Nuclei in the GAlaxy Evolution and Assembly semi-analytic model
• Spectroscopic observation of Ly$\alpha$ emitters at z~7.7 and implications on re-ionization
• A New Method to Measure the Post-Reionization Ionizing Background from the Joint Distribution of Lyman-$\alpha$ and Lyman-$\beta$ Forest Transmission
• Cosmic Reionization After Planck and Before JWST: An Analytic Approach
• The first measurement of the quasar lifetime distribution
• Two more, bright, z > 6 quasars from VST ATLAS and WISE
• Rapid growth of black holes accompanied with hot or warm outflows exposed to anisotropic super-Eddington radiation
• The Magellan M2FS Spectroscopic Survey of High-$z$ Galaxies: Lyα Emitters at $z\approx 6.6$ and the Evolution of Lyα Luminosity Function over $z\approx 5.7-6.6$
• The Evolution of the HeII-Ionizing Background at Redshifts 2.3<z<3.8 Inferred from a Statistical Sample of 24 HST/COS HeII Ly$\alpha$ Absorption Spectra
• The Extremely Luminous Quasar Survey in the Sloan Digital Sky Survey footprint. III. The South Galactic Cap Sample and the Quasar Luminosity Function at Cosmic Noon
• He II Proximity Effect and the Lifetime of Quasars
• Finding the brightest cosmic beacons in the Southern Hemisphere
• Large-Scale Fluctuations in the HeII Lyman-alpha Forest and HeII Reionization
• A high space density of L* Active Galactic Nuclei at z~4 in the COSMOS field
• The space density of ultra-luminous QSOs at the end of reionization epoch by the QUBRICS Survey and the AGN contribution to the hydrogen ionizing background
• The spectroscopic follow-up of the QUBRICS bright quasar survey
• The Luminosity Function of bright QSOs at z~4 and implications for the cosmic ionizing background
• Press-Schechter primordial black hole mass functions and their observational constraints
• The Probabilistic Random Forest applied to the selection of quasar candidates in the QUBRICS Survey
• Pure Density Evolution of the Ultraviolet Quasar Luminosity Function at $2\lesssim z\lesssim 6$
• Constraining the cosmic UV background at z>3 with MUSE Lyman-α emission observations
• CHORUS IV: Mapping the Spatially Inhomogeneous Cosmic Reionization with Subaru HSC
• Constraining the reionization history with CMB and spectroscopic observations
• On the Evolution of the Star Formation Rate Function of Massive Galaxies. Constraints at 0.4<z<1.8 from the GOODS-MUSIC Catalogue

Cited by in corpus (6)

• A CEERS Discovery of an Accreting Supermassive Black Hole 570 Myr after the Big Bang: Identifying a Progenitor of Massive z > 6 Quasars
• UNCOVERing the contribution of black holes to reionization in the JWST era
• Spectroscopy of QUBRICS quasar candidates: 1672 new redshifts and a Golden Sample for the Sandage Test of the Redshift Drift
• Galaxy Formation and Symbiotic Evolution with the Inter-Galactic Medium in the Age of ELT-ANDES
• Estimating the completeness of the QUBRICS Survey with 3501 QSO redshifts from Gaia DR3 spectra
• Detecting the signature of helium reionization through 3HeII 3.46cm line-intensity mapping