An Optically Faint Quasar Survey at z~5 in the CFHTLS Wide Field: Estimates of the Black Hole Masses and Eddington Ratios

Abstract

We present the result of our spectroscopic follow-up observation for faint quasar candidates at z~5 in a part of the Canada-France-Hawaii Telescope Legacy Survey wide field. We select nine photometric candidates and identify three z~5 faint quasars, one z~4 faint quasar, and a late-type star. Since two faint quasar spectra show Civ emission line without suffering from a heavy atmospheric absorption, we estimate the black hole mass (M${}_{BH}$) and Eddington ratio (L/L${}_{Edd}$) of them. The inferred log M${}_{BH}$ are 9.04+/-0.14 and 8.53+/-0.20, respectively. In addition, the inferred log (L/L${}_{Edd}$) are -1.00+/-0.15 and -0.42+/-0.22, respectively. If we adopt that L/L${}_{Edd}$= constant or $\propto$ (1+z)^2, the seed black hole masses (M${}_{seed}$) of our z~5 faint quasars are expected to be >10^5 M${}_{\odot }$ in most cases. We also compare the observational results with a mass accretion model where angular momentum is lost due to supernova explosions (Kawakatu & Wada 2008). Accordingly, M${}_{BH}$ of the z~5 faint quasars in our sample can be explained even if M${}_{seed}$ is ~10^3M${}_{\odot }$. Since z~6 luminous qusars and our z~5 faint quasars are not on the same evolutionary track, z~6 luminous quasars and our z~5 quasars are not the same populations but different populations, due to the difference of a period of the mass supply from host galaxies. Furthermore, we confirm that one can explain M${}_{BH}$ of z~6 luminous quasars and our z~5 faint quasars even if their seed black holes of them are formed at z~7.

16 pages, 8 figures, Accepted for publication in The Astrophysical Journal

References in corpus (33)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• A Catalog of Quasar Properties from SDSS DR7
• 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
• Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-Thick Populations
• The WFCAM Science Archive
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• The Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars within the first Gyr of the universe
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• Four quasars above redshift 6 discovered by the Canada-France High-z Quasar Survey
• Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical Abundances, Black Hole Masses, and MgII Absorption
• Black hole masses and enrichment of z ~ 6 SDSS quasars
• MegaPipe: the MegaCam image stacking pipeline at the Canadian Astronomical Data Centre
• Correcting CIV-Based Virial Black Hole Masses
• A Survey of z~6 Quasars in the SDSS Deep Stripe: I. a Flux-Limited Sample at z_{AB}<21
• The identification of z-dropouts in Pan-STARRS1: three quasars at 6.5<z<6.7
• Black-Hole Mass and Growth Rate at High Redshift
• Discovery of eight z ~ 6 quasars from Pan-STARRS1
• Six more quasars at redshift 6 discovered by the Canada-France High-z Quasar Survey
• Detailed Shape and Evolutionary Behavior of the X-ray Luminosity Function of Active Galactic Nuclei
• The Subaru high-z quasar survey: discovery of faint z~6 quasars
• Coevolution of Supermassive Black Holes and Circumnuclear Disks
• High-resolution VLA Imaging of SDSS Stripe 82 at 1.4 GHz
• Two bright z > 6 quasars from VST ATLAS and a new method of optical plus mid-infra-red colour selection
• A survey of luminous high-redshift quasars with SDSS and WISE II. the bright end of the quasar luminosity function at z ~ 5
• Rest-frame Optical Spectra and Black Hole Masses of 3<z<6 Quasars
• Discovery of Eight z ~ 6 Quasars in the Sloan Digital Sky Survey Overlap Regions
• Anti-hierarchical evolution of the Active Galactic Nucleus space density in a hierarchical universe
• SDSS J013127.34$-$032100.1: A newly discovered radio-loud quasar at $z=5.18$ with extremely high luminosity
• The Subaru/XMM-Newton Deep Survey (SXDS) -VII. Clustering Segregation with Ultraviolet and Optical Luminosities of Lyman-Break Galaxies at z~3
• The Infrared Medium-deep Survey. III. Survey of Luminous Quasars at 4.7 $\le$ z $\le$ 5.4
• Revisiting the Completeness and the Luminosity Function in High-Redshift Low-Luminosity Quasar Surveys
• An Exploratory Search for z~6 Quasars in the UKIDSS Early Data Release

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• SILVERRUSH X: Machine Learning-Aided Selection of $9318$ LAEs at $z=2.2$, $3.3$, $4.9$, $5.7$, $6.6$, and $7.0$ from the HSC SSP and CHORUS Survey Data