THE FINAL SDSS HIGH-REDSHIFT QUASAR SAMPLE OF 52 QUASARS AT z > 5.7

By Linhua Jiang, I. McGreer, Xiaohui Fan, M. Strauss, E. Bañados, Robert H. Becker, F. Bian, Kara Farnsworth, Yue Shen, Feige Wang and 7 more. 2016

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We present the discovery of nine quasars at identified in the Sloan Digital Sky Survey (SDSS) imaging data. This completes our survey of quasars in the SDSS footprint. Our final sample consists of 52 quasars at , including 29 quasars with mag selected from 11,240 deg2 of the SDSS single-epoch imaging survey (the main survey), 10 quasars with selected from 4223 deg2 of the SDSS overlap regions (regions with two or more imaging scans), and 13 quasars down to mag from the 277 deg2 in Stripe 82. They span a wide luminosity range of . This well-defined sample is used to derive the quasar luminosity function (QLF) at . After combining our SDSS sample with two faint ( mag) quasars from the literature, we obtain the parameters for a double power-law fit to the QLF. The bright-end slope β of the QLF is well constrained to be . Due to the small number of low-luminosity quasars, the faint-end slope α and the characteristic magnitude are less well constrained, with and mag. The spatial density of luminous quasars, parametrized as , drops rapidly from to 6, with . Based on our fitted QLF and assuming an intergalactic medium (IGM) clumping factor of C = 3, we find that the observed quasar population cannot provide enough photons to ionize the IGM at ∼90% confidence. Quasars may still provide a significant fraction of the required photons, although much larger samples of faint quasars are needed for more stringent constraints on the quasar contribution to reionization.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/54feee14178f8a4528dc1206850a92116ed7cedc

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Citations in the corpus

Project Overview of the Beijing–Arizona Sky Survey (2017, background): “The SDSS has provided the most comprehensive optical census of AGN evolution so far (Ross et al. 2013), and opened a window for studying high-redshift quasar close to the end of cosmic reionization (Fan et al. 2006; Jiang et al. 2016).”
The Rise of Faint, Red Active Galactic Nuclei at z > 4: A Sample of Little Red Dots in the JWST Extragalactic Legacy Fields (2025, unknown): “…that are 2 – 3 dex below that of bright quasars identi ﬁ ed by ground-based surveys at similar redshifts ( e.g., C. J. Willott et al. 2010; L. Jiang et al. 2016; C. Mazzucchelli et al. 2017; Y. Matsuoka et al. 2022; J. Yang et al. 2023 ) and are powered by black holes ( BHs ) with masses…”
The bolometric quasar luminosity function at z = 0–7 (2020, methodology): “…Richards et al. 2006a; Croom et al. 2009; Willott et al. 2010; Glikman et al. 2011; Ross et al. 2013; McGreer et al. 2013; Kashikawa et al. 2015; Jiang et al. 2016), soft X-ray (e.g., Maccacaro et al. 1991; Boyle et al. 1993; Jones et al. 1997; Page et al. 1997; Miyaji et al. 2000; Hasinger et…”
Physical Properties of 15 Quasars at z ≳ 6.5 (2017, background): “…discovered at 5.4 < z < 6.4, mainly thanks to the advent of largearea surveys: e.g., the Sloan Digital Sky Survey (SDSS; Fan et al. 2000, 2003, 2006, Jiang et al. 2016, Wang et al. 2016, 2017); the Canada-France High-redshift Quasar Survey (CFHQS; Willott et al. 2007, 2009, 2010a,b); the UK…”
SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14–21 deg2 sky (2017, background): “…studies suggest the existence of (faint) AGNs at z ∼ 6− 7 (e.g., Willott et al. 2010; Mortlock et al. 2011; Kashikawa et al. 2015; Giallongo et al. 2015; Jiang et al. 2016; Bowler et al. 2017b; Parsa et al. 2017 ), which may systematically enhance the bright end of our z=5.7 and 6.6 Lyα LFs.”
Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). V. Quasar Luminosity Function and Contribution to Cosmic Reionization at z = 6 (2018, methodology): “The derived LF agrees well with the previous results from the SDSS (Jiang et al. 2016) and the CFHQS (Willott et al. 2010) at M1450 < −25 mag, and significantly improves the accuracy at fainter magnitudes.”
Evolution of the AGN UV luminosity function from redshift 7.5 (2018, methodology): “MNRAS 000, 1–30 (2018) end of the luminosity function (e.g., Jiang et al. 2016), a comparison with the luminosity function at lower redshifts (z < 5.5) suggests that these AGN should instead be understood to describe the faint-end of a double power law.”
Great Optically Luminous Dropout Research Using Subaru HSC (GOLDRUSH). I. UV Luminosity Functions at $z \sim 4-7$ Derived with the Half-Million Dropouts on the 100 deg$^2$ Sky (2017, result): “In addition, Figure 8 shows that our bright-end LF results for dropouts are broadly consistent with those of AGNs at z ∼ 6 taken from Willott et al. (2010b), Kashikawa et al. (2015), and Jiang et al. (2016).”
New constraints on lyman-α opacity with a sample of 62 quasars at z > 5.7 (2018, methodology): “Jiang et al. (2016) presented the 52 final quasars discovered by the SDSS, most of which are included in this work.”
An ALMA [C ii] Survey of 27 Quasars at z > 5.94 (2018, unknown): “…in the literature at >z 5.5, 119 at >z 6.0, 15 at >z 6.5, and only two at >z 7.0 (see, e.g., Fan et al. 2006; Mortlock et al. 2011; Venemans et al. 2013; Bañados et al. 2016, 2018; Jiang et al. 2016; Matsuoka et al. 2016, 2017; Mazzucchelli et al. 2017; Wang et al. 2017, and references therein).”