A hyperluminous obscured quasar at a redshift of z ~ 4.3

Abstract

In this work we report the discovery of the hyperluminous galaxy HELP_J100156.75+022344.7 at the photometric redshift of z ~ 4.3. The galaxy was discovered in the Cosmological Evolution Survey (COSMOS) field, one of the fields studied by the Herschel Extragalactic Legacy Project (HELP). We present the spectral energy distribution (SED) of the galaxy and fit it with the CYprus models for Galaxies and their NUclear Spectra (CYGNUS) multi-component radiative transfer models. We find that its emission is dominated by an obscured quasar with a predicted total 1-1000um luminosity of $3.91_{-0.55}^{+1.69}\times 10^{13}{L}_{\odot }$ and an active galactic nucleus (AGN) fraction of ~89%. We also fit HELP_J100156.75+022344.7 with the Code Investigating GALaxy Emission (CIGALE) code and find a similar result. This is only the second z > 4 hyperluminous obscured quasar discovered to date. The discovery of HELP_J100156.75+022344.7 in the ~ 2deg^2 COSMOS field implies that a large number of obscured hyperluminous quasars may lie in the HELP fields which cover ~ 1300deg^2. If this is confirmed, tension between supermassive black hole evolution models and observations will be alleviated. We estimate the space density of objects like HELP_J100156.75+022344.7 at z ~ 4.5 to be $\sim 1.8\times 10^{-8}$Mpc${}^{-3}$. This is slightly higher than the space density of coeval hyperluminous optically selected quasars suggesting that the obscuring torus in z > 4 quasars may have a covering factor $\gtrsim 50\%$.

Accepted for publication in Monthly Notices of the Royal Astronomical Society Letters. The CYGNUS models used in this work are available at https://arc.euc.ac.cy/cygnus-project-arc/

References in corpus (17)

• The Cosmic Evolution Survey (COSMOS) -- Overview
• A luminous quasar at a redshift of z = 7.085
• An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30
• Pōniuā'ena: A Luminous $z=7.5$ Quasar Hosting a 1.5 Billion Solar Mass Black Hole
• Metallicity Evolution of Damped Lyman-alpha Systems out to z~5
• The XMM-Newton wide-field survey in the COSMOS field. The point-like X-ray source catalogue
• The First Hyper-Luminous Infrared Galaxy Discovered by WISE
• High-redshift AGN in the Chandra Deep Fields: the obscured fraction and space density of the sub-$L_{\ast }$ population
• The Most Luminous Galaxies Discovered by WISE
• Core-collapse supernovae missed by optical surveys
• HELP: A catalogue of 170 million objects, selected at 0.36-4.5 $\mu$m, from 1270 deg.${}^2$ of prime extragalactic fields
• Infrared Selection of Obscured Active Galactic Nuclei in the COSMOS Field
• Submillimetre observations of WISE/radio-selected AGN and their environments
• Galaxy evolution studies with the SPace IR telescope for Cosmology and Astrophysics (SPICA): the power of IR spectroscopy
• A model for the infrared emission of FSC 10214+4724
• The role of the most luminous, obscured AGN in galaxy assembly at z~2
• The mid-infrared and CO gas properties of an extreme star-forming FeLoBAL quasar

Cited by in corpus (12)

• HELP: The Herschel Extragalactic Legacy Project
• A new look at local ultraluminous infrared galaxies: the atlas and radiative transfer models of their complex physics
• Energetic nuclear transients in luminous and ultraluminous infrared galaxies
• Core-collapse supernova subtypes in luminous infrared galaxies
• SMART: spectral energy distributions Markov chain analysis with radiative transfer models
• Classification of local ultraluminous infrared galaxies and quasars with kernel principal component analysis
• Graph Theoretical Analysis of local ultraluminous infrared galaxies and quasars
• Exploring the properties of the obscured hyperluminous quasar COS-87259 at z=6.853
• A comparative study of galaxy evolution with four different active galactic nucleus torus models and two different host geometries
• Reconstructing the mid-infrared spectra of galaxies using ultraviolet to submillimeter photometry and Deep Generative Networks
• A comparative study of ultraluminous infrared galaxies in the IRAS and SDSS Surveys
• The Nature of Hyperluminous Infrared Galaxies