Quasar Luminosity Function at z = 7

Matsuoka, Yoshiki; Onoue, Masafusa; Iwasawa, K.; Strauss, Michael A.; Kashikawa, Nobunari; Izumi, Teruo; Nagao, Tohru; Imanishi, Masatoshi; Akiyama, Masayuki; Silverman, John D.; Asami, Naoko; Bosch, James; Furusawa, Hisanori; Goto, Tomotsugu; Gunn, James E.; Harikane, Yuichi; Ikeda, Hiroyuki; Inayoshi, Kohei; Ishimoto, Rikako; Kawaguchi, Toshihiro; Kikuta, Satoshi; Kohno, Kotaro; Komiyama, Yutaka; Lee, Chien‐Hsiu; Lupton, Robert H.; Minezaki, Takeo; Miyazaki, Satoshi; Murayama, Hitoshi; Nishizawa, Atsushi J.; Oguri, Masamune; Ono, Yoshiyasu; Oogi, Taira; Ouchi, Masami; Price, P. A.; Sameshima, Hiroaki; Sugiyama, Naoshi; Tait, Philip J.; Takada, Masahiro; Takahashi, Ayumi; Takata, Tadafumi; Tanaka, Masayuki; Toba, Yoshiki; Wang, Shiang‐Yu; Yamashita, Takuji

doi:10.3847/2041-8213/acd69f

Cited by 25 publications

(20 citation statements)

References 54 publications

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“…The same calculation is carried out in the HSC-Wide survey, giving comparable results in terms of QSO space density. These z ∼ 5 QSO luminosity functions are ∼2-3 times larger than the ones derived by Yang et al (2016) Matsuoka et al (2023), and model 4 of Pan et al (2022). The maximum likelihood approach summarized in Table 3 confirms the results obtained with nonparametric luminosity function analysis.…”

Section: Discussionsupporting

confidence: 83%

“…This incompleteness is even more exacerbated in the case of shallow surveys, where the photometric scatter, especially in the bands used for dropout, could undermine the completeness of the selection criteria adopted. It is thus not surprising at all that in the past there were a number of claims of a low space density of high-z QSOs (e.g., Yang et al 2016;McGreer et al 2018;Kulkarni et al 2019;Kim et al 2020;Niida et al 2020;Kim & Im 2021;Jiang et al 2022;Onken et al 2022;Pan et al 2022;Shin et al 2022;Matsuoka et al 2023;Schindler et al 2023), which are not supported by the data of this paper. A possible way out to have a high level of completeness, while keeping the efficiency of spectroscopic surveys acceptable, is to adopt selection methods based on machine learning and iterative removal of low-probability candidates (G. Calderone et al, in preparation).…”

Section: Comparison With Recent Surveys Of Z ∼ 5 Qsoscontrasting

confidence: 80%

“…Given a mean free path of 17.4 proper Mpc at z = 4.75, it turns out that AGN are able to produce ∼50%-100% of the ionizing background at the end of the reionization epoch. In particular, recent claims of a negligible role of AGN in H I reionization, based on earlier luminosity function estimates (e.g., Yang et al 2016;McGreer et al 2018;Kulkarni et al 2019;Kim et al 2020;Niida et al 2020;Kim & Im 2021;Jiang et al 2022;Onken et al 2022;Pan et al 2022;Shin et al 2022;Harikane et al 2023;Matsuoka et al 2023;Schindler et al 2023), are formally excluded at more than the 2σ level, given our results here on the luminosity function of z ∼ 5 QSOs.…”

Section: Discussionmentioning

confidence: 52%

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Crossing the Rubicon of Reionization with z ∼ 5 QSOs

Grazian,

Boutsia,

Giallongo

et al. 2023

ApJ

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One of the key open questions in cosmology is the nature of sources that completed cosmological hydrogen reionization at z ∼ 5.2. High-z primeval galaxies have been long considered the main drivers of reionization, with a minor role played by high-z active galactic nuclei (AGN). However, in order to confirm this scenario, it is fundamental to measure the photoionization rate produced by active SMBHs close to the Epoch of Reionization. Given the pivotal role played by spectroscopically complete observations of high-z QSOs, in this paper we present the first results of the RUBICON (Reionizing the Universe with Bright Cosmological Nuclei) survey. It consists of a color-selected sample of bona fide z ∼ 5 QSO candidates from the Hyper Suprime-Cam Subaru Strategic Survey. Our QSO candidates have been validated both by photometric redshifts based on spectral energy distribution fitting and by spectroscopic redshifts, confirming that they lie at 4.5 < z spec < 5.2. A relatively high space density of QSOs (Φ ∼ 1.4 × 10−8 c Mpc−3) is thus confirmed at z ∼ 5 and M 1450 ∼ −27, consistent with a pure density evolution of the AGN luminosity function from z = 4 to z = 5, with a mild density evolution rate of 0.25 dex. This indicates that AGN could play a nonnegligible role in cosmic reionization. The Rubicon of reionization has been crossed.

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Section: Discussionsupporting

confidence: 83%

Section: Comparison With Recent Surveys Of Z ∼ 5 Qsoscontrasting

confidence: 80%

Section: Discussionmentioning

confidence: 52%

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Crossing the Rubicon of Reionization with z ∼ 5 QSOs

Grazian,

Boutsia,

Giallongo

et al. 2023

ApJ

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“…Until the launch of the James Webb Space Telescope (JWST), the earliest black holes known were a handful of extremely UV-luminous z ≈ 7 quasars (e.g., Mortlock et al 2011;Bañados et al 2018;Matsuoka et al 2018Matsuoka et al , 2023. While Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.…”

Section: Introductionmentioning

confidence: 99%

UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec—Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1

Goulding,

Greene,

Setton

et al. 2023

ApJL

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The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from “seeds” to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z > 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at z = 10.073 ± 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered z ≈ 10 galaxies, characterized primarily by star formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar-mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates ( M ⋆ ∼ 1.4 − 0.4 + 0.3 × 10 8 M ⊙). Given the predicted BH mass (M BH ∼ 107–108 M ⊙), the resulting ratio of M BH/M ⋆ remains 2 to 3 orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution.

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“…The recent James Webb Space Telescope (JWST) photometric and spectroscopic surveys have discovered a large number of active galactic nuclei (AGN) candidates over the redshifts z ∼ 4.5-7, especially helping to bridge the gap of missing faint AGN with M UV < − 25 (Matsuoka et al 2023). The AGN candidates are identified based on X-ray, broad Hβ, and high-ionization lines.…”

Section: Introductionmentioning

confidence: 99%

Constraining the AGN Luminosity Function from JWST with the X-Ray Background

Padmanabhan,

Loeb

2023

ApJL

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We predict the X-ray background (XRB) expected from the population of quasars detected by the James Webb Space Telescope spectroscopic surveys over the redshift range z ∼ 4–7. We find that the measured UV emissivities imply a ∼10 times higher unresolved XRB than constrained by current experiments. We illustrate the difficulty of simultaneously matching the faint end of the quasar luminosity function and the XRB constraints. We discuss possible origins and consequences of this discrepancy.

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Quasar Luminosity Function at z = 7

Cited by 25 publications

References 54 publications

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

Crossing the Rubicon of Reionization with z ∼ 5 QSOs

UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec—Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1

Constraining the AGN Luminosity Function from JWST with the X-Ray Background

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