Exploring Reionization-Era Quasars III: Discovery of 16 Quasars at $6.4\lesssim z \lesssim 6.9$ with DESI Legacy Imaging Surveys and UKIRT Hemisphere Survey and Quasar Luminosity Function at $z\sim6.7$

Wang, Feige; Yang, Jinyi; Fan, Xiaohui; Wu, Xue-Bing; Yue, Minghao; Li, Jiang-Tao; Bian, Fuyan; Jiang, Linhua; Bañados, Eduardo; Schindler, Jan-Torge; Findlay, Joseph R.; Davies, Frederick B.; Decarli, Roberto; Farina, Emanuele P.; Green, Richard; Hennawi, Joseph F.; Huang, Yun-Hsin; Mazzuccheli, Chiara; McGreer, Ian D.; Venemans, Bram; Walter, Fabian; Dye, Simon; Lyke, Brad W.; Myers, Adam D.; Nunez, Evan Haze

doi:10.48550/arxiv.1810.11926

Cited by 13 publications

(23 citation statements)

References 74 publications

(171 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The current decade has featured the following progress in the area of high-redshift quasar surveys: -the discovery of z > 7 quasars from near-IR surveys (Mortlock et al 2011, Bañados et al 2018; -systematic studies of faint quasars at z ∼ 6 from deep optical surveys (Matsuoka et al 2018); and -the assembly of statistical samples of luminous reionization-era quasars at z > 6.5 from a new generation of wide-field imaging surveys (Wang et al 2019).…”

Section: Epoch Of the First Luminous Quasarsmentioning

confidence: 99%

“…These surveys show that while the overall shape of the quasar luminosity function evolves only modestly up to z ∼ 6 (Matsuoka et al 2018), its normalization, in other words the overall density of luminous quasars, evolves strongly with redshift (Jiang et al 2016, Wang et al 2019. When modeled as an exponential decline with redshift, the density of luminous quasars drops by a factor of ∼ 3 per unit redshift at z = 3 − 5; this decline accelerates to a factor of ∼ 6 per unit redshift at z = 5 − 7.…”

Section: Epoch Of the First Luminous Quasarsmentioning

confidence: 99%

“…This latter timescale is comparable to the Eddington timescale of SMBH growth of about 45 million years (assuming a radiative efficiency of Figure 1: Left: The density of luminous quasars evolves rapidly in the early universe. Extrapolating from measurements at z = 5 − 7, there will be only ∼ 1 luminous quasar powered by a billion M BH in the entire observable universe at z 9 (Wang et al 2019). Right: Forecast of quasar discoveries in wide-field imaging surveys in the next decade.…”

Section: Epoch Of the First Luminous Quasarsmentioning

confidence: 99%

“…Figure 1 (right panel) forecasts the number of quasars that can be detected in these surveys, based on the quasar luminosity function shape at z ∼ 6 (Matsuoka et al 2018) and a normalization extrapolating from the measurements at z ∼ 5 − 7 (Wang et al 2019). For each survey, its limiting magnitude is determined by the depth of the "dropout" band below the redshifted Lyman break wavelength.…”

Section: High-redshift Quasar Surveys In the 2020smentioning

confidence: 99%

“…They will be faint, with AB magnitudes of 22 − 25, requiring observations on large-aperture telescopes. Past experience suggests that the spectroscopic success rate of spectroscopic identificaiton at the new redshift frontier will be low: Wang et al (2019) reported a success rate of quasar identification at z ∼ 6.5 to be > 30%; current yields at z > 7 are much lower (< 10%). We expect this efficiency to improve as more quasars are discovered and the size of training sets expanded, but the identifications at the highest-redshift frontier will continue to be challenging and highly resource-intensive.…”

Section: High-redshift Quasar Surveys In the 2020smentioning

confidence: 99%

See 4 more Smart Citations

The First Luminous Quasars and Their Host Galaxies

Fan¹,

Barth²,

Bañados³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

The discovery of luminous quasars at redshifts up to 7.5 demonstrates the existence of several billion M supermassive black holes (SMBHs) less than a billion years after the Big Bang. They are accompanied by intense star formation in their host galaxies, pinpointing sites of massive galaxy assembly in the early universe, while their absorption spectra reveal an increasing neutral intergalactic medium (IGM) at the epoch of reionization. Extrapolating from the rapid evolution of the quasar density at z = 5 − 7, we expect that there is only one luminous quasar powered by a billion M SMBH in the entire observable universe at z ∼ 9. In the next decade, new wide-field, deep nearinfrared (NIR) sky surveys will push the redshift frontier to the first luminous quasars at z ∼ 9 − 10; the combination with new deep X-ray surveys will probe fainter quasar populations that trace earlier phases of SMBH growth. The identification of these record-breaking quasars, and the measurements of their BH masses and accretion properties require sensitive spectroscopic observations with next generation of ground-based and space telescopes at NIR wavelengths. High-resolution integral-field spectroscopy at NIR, and observations at millimeter and radio wavelengths, will together provide a panchromatic view of the quasar host galaxies and their galactic environment at cosmic dawn, connecting SMBH growth with the rise of the earliest massive galaxies. Systematic surveys and multiwavelength follow-up observations of the earliest luminous quasars will strongly constrain the seeding and growth of the first SMBHs in the universe, and provide the best lines of sight to study the history of reionization.

show abstract

Section: Epoch Of the First Luminous Quasarsmentioning

confidence: 99%

Section: Epoch Of the First Luminous Quasarsmentioning

confidence: 99%

Section: Epoch Of the First Luminous Quasarsmentioning

confidence: 99%

Section: High-redshift Quasar Surveys In the 2020smentioning

confidence: 99%

Section: High-redshift Quasar Surveys In the 2020smentioning

confidence: 99%

See 3 more Smart Citations

The First Luminous Quasars and Their Host Galaxies

Fan¹,

Barth²,

Bañados³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

The X-ray properties of z > 6 quasars: no evident evolution of accretion physics in the first Gyr of the Universe

Vito

Brandt

Bauer

et al. 2019

A&A

110

150

View full text Add to dashboard Cite

Context. X-ray emission from quasars (QSOs) has been used to assess supermassive black hole (SMBH) accretion properties up to z ≈ 6. However, at z > 6 only ≈ 15 QSOs are covered by sensitive X-ray observations, preventing a statistically significant investigation of the X-ray properties of the QSO population in the first Gyr of the Universe. Aims. We present new Chandra observations of a sample of 10 z > 6 QSOs, selected to have virial black-hole mass estimates from Mg II line spectroscopy (log M BH M = 8.5 − 9.6). Adding archival X-ray data for an additional 15 z > 6 QSOs, we investigate the X-ray properties of the QSO population in the first Gyr of the Universe, focusing in particular on the L UV − L X relation, which is traced by the α ox parameter, and the shape of their X-ray spectra. Methods. We performed photometric analyses to derive estimates of the X-ray luminosities of our z > 6 QSOs, and thus their α ox values and bolometric corrections (K bol = L bol /L X ). We compared the resulting α ox and K bol distributions with the results found for QSO samples at lower redshift, and ran several statistical tests to check for a possible evolution of the L UV − L X relation. Finally, we performed a basic X-ray spectral analysis of the brightest z > 6 QSOs to derive their individual photon indices, and joint spectral analysis of the whole sample to estimate the average photon index. Results. We detected seven of the new Chandra targets in at least one standard energy band, while two more are detected discarding energies E > 5 keV, where background dominates. We confirm a lack of significant evolution of α ox with redshift, extending the results from previous works up to z > 6 with a statistically significant QSO sample, and the trend of an increasing bolometric correction with increasing luminosity found for QSOs at lower redshifts. The average power-law photon index of our sample ( Γ = 2.20 +0.39 −0.34 and Γ = 2.13 +0.13 −0.13 for sources with < 30 and > 30 net counts, respectively) is slightly steeper than, but still consistent with, typical QSOs at z = 1 − 6. Conclusions. All these results point toward a lack of substantial evolution of the inner accretion-disk/hot-corona structure in QSOs from low redshift to z > 6. Our data hint at generally high Eddington ratios at z > 6.

show abstract

The near and mid-infrared photometric properties of known redshift z ≥ 5 quasars

Ross

Cross

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We assemble a catalogue of 463 spectroscopically confirmed very high (z ≥ 5.00) redshift quasars and report their near-(ZY JHK s /K) and mid-(WISE W1234) infrared properties. 97% of the VHzQ sample is detected in one or more NIR (ZY JHK/K s ) band, with lack of coverage rather than lack of depth being the reason for the nondetections. 362 (78%) of the very high redshift quasars are detected at 3.4µm in the W1 band from the unWISE catalog and all of the z ≥ 7 quasars are detected in both unWISE W1 and W2. Using archival WFCAM/UKIRT and VIRCAM/VISTA data we check for photometric variability that might be expected from super-Eddington accretion. We find 32 of the quasars have sufficient NIR measurements and signal-tonoise to look for variability. Weak variability was detected in multiple bands of SDSS J0959+0227, and very marginally in the Y -band of MMT J0215-0529. Two other quasars, SDSS J0349+0034 and SDSS J2220-0101 had significant differences between their WFCAM and VISTA magnitudes in one band. With supermassive black hole accretion likely to be redshift invariant up to very high-redshift, further monitoring of these sources is warranted. All the data, analysis codes and plots used and generated here can be found at: github.com/d80b2t/VHzQ.

show abstract

Exploring Reionization-Era Quasars III: Discovery of 16 Quasars at $6.4\lesssim z \lesssim 6.9$ with DESI Legacy Imaging Surveys and UKIRT Hemisphere Survey and Quasar Luminosity Function at $z\sim6.7$

Cited by 13 publications

References 74 publications

The First Luminous Quasars and Their Host Galaxies

The First Luminous Quasars and Their Host Galaxies

The X-ray properties of z > 6 quasars: no evident evolution of accretion physics in the first Gyr of the Universe

The near and mid-infrared photometric properties of known redshift z ≥ 5 quasars

Contact Info

Product

Resources

About