The Faint End of the Quasar Luminosity Function at z ∼ 5 from the Subaru Hyper Suprime-Cam Survey

Niida, Mana; Nagao, Tohru; Ikeda, Hiroyuki; Akiyama, Masayuki; He, Wanqiu; Matsuoka, Kenta; Toba, Yoshiki; Onoue, Masafusa; Kobayashi, Masakazu A. R.; Taniguchi, Yoshiaki; Furusawa, Hisanori; Harikane, Yuichi; Imanishi, Masatoshi; Kashikawa, Nobunari; Kawaguchi, Toshihiro; Komiyama, Yutaka; Shirakata, Hikari; Terashima, Yuichi; Ueda, Yoshihiro

doi:10.3847/1538-4357/abbe11

Cited by 48 publications

(83 citation statements)

References 93 publications

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“…At these very bright luminosities (M 1450 ≤ −28.5), our space density is a factor of ∼ 3 higher than previous determinations by Yang et al (2016);McGreer et al (2018); Niida et al (2020) or than the best fit by Kulkarni et al (2019); Giallongo et al (2019); Grazian et al (2020); Kim & Im (2021). Since our luminosity function has been derived simply by dividing the number of confirmed QSOs at z ∼ 5 by the cosmological volume of the Universe corresponding to 4.5 < z < 5.0 and 12,400 sq.…”

Section: Determination Of the Space Densitymentioning

confidence: 49%

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

Grazian,

Giallongo,

Boutsia

et al. 2021

Preprint

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Motivated by evidences favoring a rapid and late hydrogen reionization process completing at z ∼ 5.2 − 5.5 and mainly driven by rare and luminous sources, we have reassessed the estimate of the space density of ultra-luminous QSOs at z ∼ 5 in the framework of the QUBRICS survey. A ∼ 90% complete sample of 14 spectroscopically confirmed QSOs at M 1450 ≤ −28.3 and 4.5 ≤ z ≤ 5.0 has been derived in an area of 12, 400 sq. deg., thanks to multi-wavelength selection and GAIA astrometry. The space density of z ∼ 5 QSOs within −29.3 ≤ M 1450 ≤ −28.3 is three times higher than previous determinations. Our results suggest a steep bright-end slope for the QSO luminosity function at z ∼ 5 and a mild redshift evolution of the space density of ultra-bright QSOs (M 1450 ∼ −28.5) at 3 < z < 5.5, in agreement with the redshift evolution of the much fainter AGN population at M 1450 ∼ −23. These findings are consistent with a pure density evolution for the AGN population at z > 3. Adopting our z ∼ 4 QSO luminosity function and applying a mild density evolution in redshift, a photo-ionization rate of Γ HI = 0.46 +0.17 −0.09 × 10 −12 s −1 has been obtained at z = 4.75, assuming an escape fraction of ∼ 70% and a steep faint-end slope of the AGN luminosity function. The derived photo-ionization rate is ∼ 50 − 100% of the ionizing background measured at the end of the reionization epoch, suggesting that AGNs could play an important role in the cosmological reionization process.

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Section: Determination Of the Space Densitymentioning

confidence: 49%

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

Grazian,

Giallongo,

Boutsia

et al. 2021

Preprint

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“…A linear regression to the cumulative points trivially translates into LF slopes of = −3.19 ± 0.07 at ≈ 4.6 and = −3.84 ± 0.08 at ≈ 5. Previous work found slopes in the same range despite using less complete samples, with data-driven 'best' free fits ranging from = −3.94 by Niida et al (2020) and = −3.80 by Y16 to = −3.50 by Kim et al (2020). Interestingly, all three of these works have also considered fixed-slope fits, using = −2.9, −3 or −3.03, seemingly to accommodate the Jiang et al (2009) slope at = 6, which is, however, not very tightly constrained.…”

Section: Bright-end Slope Of the Luminosity Functionmentioning

confidence: 77%

“…Although various other works in the literature have updated the ∼ 5 QSO LF (e.g. McGreer et al 2018;Kim et al 2020;Niida et al 2020), progress in this area is currently focused on the persistent uncertainties at the faint end. At the bright end, the exploitation of new data sources such as Pan-STARRS led to the discovery of new objects across nearly all redshifts but not at ≈ 5 (e.g.…”

Section: Introductionmentioning

confidence: 99%

Ultraluminous high-redshift quasars from SkyMapper – II. New quasars and the bright end of the luminosity function

Onken

Wolf

Bian

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We search for ultra-luminous Quasi-Stellar Objects (QSOs) at high redshift using photometry from the SkyMapper Southern Survey Data Release 3 (DR3), in combination with 2MASS, VHS DR6, VIKING DR5, AllWISE, and CatWISE2020, as well as parallaxes and proper motions from Gaia DR2 and eDR3. We report 142 newly discovered Southern QSOs at 3.8 < z < 5.5, of which 126 have M145 < −27 ABmag and are found in a search area of 14 486 deg2. This Southern sample, utilising the Gaia astrometry to offset wider photometric colour criteria, achieves unprecedented completeness for an ultra-luminous QSO search at high redshift. In combination with already known QSOs, we construct a sample that is >80 per cent complete for M145 < −27.33 ABmag at z = 4.7 and for M145 < −27.73 ABmag at z = 5.4. We derive the bright end of the QSO luminosity function at restframe 145 nm for z = 4.7 − 5.4 and measure its slope to be β =−3.60 ± 0.37 and β =−3.38 ± 0.32 for two different estimates of the faint-end QSO density adopted from the literature. We also present the first z ∼ 5 QSO luminosity function at restframe 300 nm.

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“…Meanwhile, there are still debates about the QLFs at z 5. A few studies give a faint-end slope of α ∼ −2 (e.g., Jiang et al 2016;Yang et al 2016;McGreer et al 2018), while others suggest α ∼ −1.3 (Niida et al 2020;Kim et al 2020). In this work, we use the HSC-based high-redshift QLFs which have α ∼ −1.3.…”

Section: Statistics Of Deflector Galaxiesmentioning

confidence: 99%

A Mock Catalog of Gravitationally Lensed Quasars for the LSST Survey

Yue,

Fan,

Yang

et al. 2022

Preprint

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We present a mock catalog of gravitationally lensed quasars at z qso < 7.5 with simulated images for the Rubin Observatory Legacy Survey of Space and Time (LSST). We adopt recent measurements of quasar luminosity functions to model the quasar population, and use the CosmoDC2 mock galaxy catalog to model the deflector galaxies, which successfully reproduces the observed galaxy velocity dispersion functions up to z d ∼ 1.5. The mock catalog is highly complete for lensed quasars with Einstein radius θ E > 0. 07 and quasar absolute magnitude M i < −20. We estimate that there are ∼ 10 3 lensed quasars discoverable in current imaging surveys, and LSST will increase this number to ∼ 2.4 × 10 3 . Most of the lensed quasars have image separation ∆θ > 0. 5, which will at least be marginally resolved in LSST images with seeing of ∼ 0. 7. There will be ∼ 200 quadruply-lensed quasars discoverable in the LSST. The fraction of quad lenses among all discoverable lensed quasars is about ∼ 10% − 15%, and this fraction decreases with survey depth. This mock catalog shows a large diversity in the observational features of lensed quasars, in terms of lensing separation and quasar-todeflector flux ratio. We discuss possible strategies for a complete search of lensed quasars in the LSST era.

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The Faint End of the Quasar Luminosity Function at z ∼ 5 from the Subaru Hyper Suprime-Cam Survey

Cited by 48 publications

References 93 publications

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 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

Ultraluminous high-redshift quasars from SkyMapper – II. New quasars and the bright end of the luminosity function

A Mock Catalog of Gravitationally Lensed Quasars for the LSST Survey

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