Physical Properties of 15 Quasars at z ≳ 6.5

Mazzucchelli, Chiara; Bañados, Eduardo; Venemans, Bram; Decarli, Roberto; Farina, Emanuele Paolo; Walter, Fabian; Eilers, Anna-Christina; Rix, Hans─Walter; Simcoe, Robert A.; Stern, Daniel; Fan, Xiaohui; Schlafly, Edward F.; Rosa, Gisella De; Hennawi, Joseph F.; Chambers, K.; Greiner, J.; Burgett, W. S.; Draper, P. W.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A.; Metcalfe, N.; Waters, C.; Wainscoat, R. J.

doi:10.3847/1538-4357/aa9185

Cited by 323 publications

(494 citation statements)

References 151 publications

(253 reference statements)

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“…The scarcely remaining flux at such wavelengths could lead to the larger uncertainty on the measurements. Moreover, Mazzucchelli et al (2017) used the correction function derived by Eilers et al (2017) for higher redshift QSOs, which is R NZ,corrected = R p,NZ × 10 0.4(27+M1450)/2.35 . The scale factor is 1.094 times larger than ours, resulting in a closer value of 6.33 pMpc if we multiply our result by 1.094.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the continuum estimation methods were largely different. Mazzucchelli et al (2017) performed the continuum fitting using PCA, the transmission profile at the near zone region depends on how well PCA can reconstruct the intrinsic spectrum. To overcome the shortage of the transmission measurement, we take advantage of the high resolution and high S/N rate spectrum to try two additional methods.…”

Section: Discussionmentioning

confidence: 99%

“…The information of this QSO is summarized in Table 1. We adopt the redshift calculated by Mazzucchelli et al (2017) based on [C ii] 158µm line. The spectrum of the QSO we obtained is shown in Fig.…”

Section: Datamentioning

confidence: 99%

“…Properties of PSO J006.1240+39.2219. Object R.A. (J2000) DEC. (J2000) z [C II] Rp,NZ (pMpc) RNZ,cor (pMpc) PSO J006.1240+39.2219 00:24:29.657 +39:12:00.66 6.621±0.002 a 4.19±0.06 5.79±0.09 a Reference:Mazzucchelli et al (2017) …”

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confidence: 99%

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Subaru Medium-resolution Spectra of a QSO at z = 6.62: Three Reionization Tests

Goto

Tang

et al. 2020

ApJ

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Investigating the Gunn-Peterson trough of high redshift quasars (QSOs) is a powerful way to reveal the cosmic reionization. As one of such attempts, we perform a series of analyses to examine the absorption lines observed with one of the highest redshift QSOs, PSO J006.1240+39.2219, which we previously discovered at z = 6.62. Using the Subaru telescope, we obtained medium-resolution spectrum with a total exposure time of 7.5 hours. We calculate the Lyα transmission in different redshift bins to determine the near zone radius and the optical depth at 5.6< z <6.5. We find a sudden change in the Lyα transmission at 5.75< z <5.86, which is consistent with the result from the literature. The near zone radius of the QSO is 5.79±0.09 pMpc, within the scatter of the near zone radii of other QSOs measured in previous studies. We also analyze the dark gap distribution to probe the neutral hydrogen fractions beyond the saturation limit of the Gunn-Peterson trough. We extend the measurement of the dark gaps to 5.7< z <6.3. We find that the gap widths increase with increasing redshifts, suggesting more neutral Universe at higher redshifts. However, these measurements strongly depend on the continuum modeling. As a continuum model-free attempt, we also perform the dark-pixel counting analysis, to find the upper limit of x HI ∼0.6 (0.8) at z <5.8 (z >5.8). All three analyses based on this QSO show increasingly neutral hydrogen towards higher redshifts, adding precious measurements up to z ∼6.5.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

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confidence: 99%

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Subaru Medium-resolution Spectra of a QSO at z = 6.62: Three Reionization Tests

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Tang

et al. 2020

ApJ

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“…Anguita et al 2008;Mazzucchelli et al 2017;Sharon et al 2016;Shields et al 2006;Wang et al 2013). The sample of unobscured AGN do not include the bright sources for which the IR luminosities are not available (e.g.…”

Section: Appendix C: Smg and Qso Samplesmentioning

confidence: 99%

Molecular gas content in obscured AGN at z > 1

Perna

Sargent

Brusa

et al. 2018

A&A

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Aims. The standard active galactic nuclei (AGN)-galaxy co-evolutionary scenario predicts a phase of deeply "buried" supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous quasar (QSO) is revealed ("SB-QSO evolutionary sequence"). The aim of this work is to measure the cold gas reservoir of three highly obscured QSOs to test if their gas fraction is similar to that of submillimeter galaxies (SMGs), as expected by some models, and place these measurements in the context of the SB-QSO framework. Methods. We target CO(1-0) transition in BzK4892, a Compton Thick (CT) QSO at z=2.6, CO(1-0) in BzK8608 and CO(2-1) in CDF153, two highly obscured (N H ≈ 6 × 10 23 cm −2 ) QSOs at z = 2.5 and z = 1.5, respectively. For all these targets, we place 3σ upper limits on the CO lines, with L CO < (1.5 ÷ 2.8) × 10 10 K km/s pc 2 . We also compare the molecular gas conditions of our targets with those of other systems at z > 1, considering normal star forming galaxies and SMGs, unobscured and obscured AGN from the literature. For the AGN samples, we provide an updated and (almost) complete collection of targets with CO follow-up at z > 1. Results. BzK4892 displays a high star formation efficiency (SFE = L IR /L CO > 410 L /(K km s −1 pc 2 )) and a gas fraction f gas = M gas /(M star + M gas ) < 10%. Less stringent constraints are derived for the other two targets ( f gas < 0.5 and SFE > 10 L /(K km s −1 pc 2 )). From the comparison with literature data, we found that, on average, i) obscured AGN at z > 1 are associated with higher SFE and lower f gas with respect to normal star forming galaxies and SMGs; ii) mildly and highly obscured active galaxies have comparable gas fractions; iii) the SFE of CT and obscured AGN are similar to those of unobscured AGN.Conclusions. Within the SB-QSO framework, these findings could be consistent with a scenario where feedback can impact the host galaxy already from the early phases of the SB-QSO evolutionary sequence.

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X‐HESS: A large sample of highly accreting serendipitous AGN under the XMM‐Newton microscope

et al. 2023

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The bulk of X-ray spectroscopic studies of active galactic nuclei (AGN) are focused on local (z < 0.1) sources with low-to-moderate (<0.3) Eddington ratio (𝜆 Edd ). It is then mandatory to overcome this limitation and improve our understanding of highly accreting AGN. In this work, we present the preliminary results from the analysis of a sample of ∼ 70 high-𝜆 Edd radio-quiet AGN at 0.06 ≤ z ≤ 3.3, based on the 10th release of the XMM-Newton serendipitous source catalog, that we named as XMM-Newton High-Eddington Serendipitous AGN Sample (X-HESS). Almost ∼ 35% of the X-HESS AGN have multi-epoch archival observations and ∼ 70% of the sources can rely on simultaneous OM optical data. First results reveal sources showing signatures of ultra-fast outflows and remarkable long-and short-term X-ray flux variations. Indeed in SDSS J095847.88+690532.7 (z ∼ 1.3), one of the most densely monitored objects hosting a ∼ 10 9 M ⊙ supermassive black hole, we discovered a variation of the soft X-ray flux by a factor of >2 over approximately one week (rest-frame). Large variations in the power-law continuum photon index Γ are also observed, questioning expectations from previously reported Γ − 𝜆 Edd relations, for which Γ ≥ 2 would be a ubiquitous hallmark of AGN with 𝜆 Edd ∼ 1.

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Physical Properties of 15 Quasars at z ≳ 6.5

Cited by 323 publications

References 151 publications

Subaru Medium-resolution Spectra of a QSO at z = 6.62: Three Reionization Tests

Subaru Medium-resolution Spectra of a QSO at z = 6.62: Three Reionization Tests

Molecular gas content in obscured AGN at z > 1

X‐HESS: A large sample of highly accreting serendipitous AGN under the XMM‐Newton microscope

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