Accurate Dust Temperature and Star Formation Rate in the Most Luminous z &gt; 6 Quasar in the Hyperluminous Quasars at the Epoch of Reionization (HYPERION) Sample

Tripodi, R.; Feruglio, C.; Kemper, F.; Civano, F.; Costa, Tiago; Elvis, M.; Bischetti, M.; Carniani, Stefano; Mascia, Fabio Di; D’Odorico, V.; Fiore, F.; Gallerani, S.; Ginolfi, M.; Maiolino, R.; Piconcelli, E.; Valiante, Rosa; Zappacosta, L.

doi:10.3847/2041-8213/acc58d

“…It ranges from 2.0 to 2.8, with a median of 2.5. The measured T dust and β of the Hot DOGs are similar to the most luminous quasar found at z = 6.327 (Tripodi et al 2023). A relatively high β value indicates optically thick dust in IR bands, which has also been reported in other compact starburst galaxies (e.g., Scoville et al 2017).…”

Section: Results Of the Sed Fitting And Dust Propertiessupporting

confidence: 81%

Physical Properties of Hyperluminous, Dust-obscured Quasars at z ∼ 3: Multiwavelength Spectral Energy Distribution Analysis and Cold Gas Content Revealed by ALMA

Sun 孙,

Fan 范,

Han 韩

et al. 2024

ApJ

3

0

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We present a UV to millimeter spectral energy distribution (SED) analysis of 16 hyperluminous, dust-obscured quasars at z ∼ 3, selected by the Wide-field Infrared Survey Explorer. We aim to investigate the physical properties of these quasars, with a focus on their molecular gas content. We decompose the SEDs into three components: stellar, cold dust, and active galactic nucleus (AGN). By doing so, we are able to derive and analyze the relevant properties of each component. We determine the molecular gas mass from CO line emission based on Atacama Large Millimeter/submillimeter Array (ALMA) observations. By including ALMA observations in the multiwavelength SED analysis, we derive the molecular gas fractions, gas depletion timescales, and star formation efficiencies (SFEs). Their sample median and 16th–84th quartile ranges are f gas ∼ 0.33 − 0.17 + 0.33 , t depl ∼ 39 − 28 + 85 Myr, and SFE ∼ 297 − 195 + 659 K km s−1 pc−2, respectively. Compared to main-sequence galaxies, they have lower molecular gas content and higher SFEs, similar to quasars in the literature. This suggests that the gas in these quasars is rapidly depleted, likely as the result of intense starburst activity and AGN feedback. The observed correlations between these properties and the AGN luminosities further support this scenario. Additionally, we infer the black hole to stellar mass ratio and black hole mass growth rate, which indicate significant central black hole mass assembly over short timescales. Our results are consistent with the scenario that our sample represents a short transition phase toward unobscured quasars.

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“…The dust optical depth is given by t = with T 0 = 2.73 K. Since the source is unresolved, the adopted area of the galaxy is the dust size commonly found in high-z QSOs (Shao et al 2022;Tripodi et al 2022;Walter et al 2022), which is 0 2 × 0 2, corresponding to ∼1.0 × 1.0 kpc 2 at the rest frame of our source. Dust temperature cannot be constrained with the lowfrequency data in hand; hence we fix it to T dust = 50 K. This may be considered the median value in z = 6 − 7 quasars, for which a range in dust temperature of 30 to 70 K is found (Leipski et al 2014;Schneider et al 2015;Carniani et al 2019;Wang et al 2019;Tripodi et al 2023Tripodi et al , 2022. We explore the two-dimensional parameter space using a Markov Chain Monte Carlo algorithm implemented in the EMCEE package (Foreman-Mackey et al 2013), assuming uniform priors for M dust and β.…”

Section: Discussionmentioning

confidence: 99%

“…At face value this would imply a star formation efficiency (SFE) of SFE = SFR/M(H 2 ) = 4.4 × 10 −9 yr −1 . Observations in ALMA Band 9 are needed to possibly resolve the host galaxy and tightly constrain both T dust and SFR (Tripodi et al 2023).…”

Section: Discussionmentioning

confidence: 99%

“…These quasars are powered by supermassive black holes (SMBHs) with masses from M BH = 10 8 M e up to 10 10 M e , shining close to the Eddington limit, with bolometric luminosities at the brightest end of the quasar luminosity function, L bol > 5 × 10 46 erg s −1 (Willott et al 2010;Mazzucchelli et al 2017;Onoue et al 2019). At Far-IR/submillimeter wavelengths, observations reveal the presence of copious amounts of dust (>10 8 M e ), and star formation rates (SFRs) up to 1000-3000 M e yr −1 , within the host galaxies (e.g., Maiolino et al 2005;Wang et al 2013;Feruglio et al 2018;Venemans et al 2017Venemans et al , 2020, albeit with large systematic uncertainties (Tripodi et al 2023).…”

Section: Introductionmentioning

confidence: 99%

“…This Letter is part of a series of papers (currently including Tripodi et al 2023;Zappacosta et al 2023) dedicated to the HYPerluminous quasars the Epoch of ReionizatION (HYPERION) sample. HYPERION consists of eighteen z = 6 − 7.5 luminous (L bol ∼ 10 47.3 erg s −1 ), highly accreting, and massive (M BH = 10 9 -10 10 M e ) quasars selected to be powered by SMBHs, which experienced the fastest mass growth in the first gigayear of the universe, and which are targets of a 2.4 Ms XMM-Newton Multi-Year Heritage program (Zappacosta et al 2023).…”

Section: Introductionmentioning

confidence: 99%

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First Constraints on Dense Molecular Gas at z = 7.5149 from the Quasar Pōniuā‘ena

Feruglio,

Maio,

Tripodi

et al. 2023

ApJL

5

0

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We report the detection of CO(6–5) and CO(7–6) and their underlying continua from the host galaxy of quasar J100758.264+211529.207 (Pōniuā‘ena) at z = 7.5149, obtained with the NOrthern Extended Millimeter Array. Pōniuā‘ena belongs to the HYPerluminous quasars at the Epoch of ReionizatION sample of 18 z > 6 quasars selected to be powered by supermassive black holes, which experienced the fastest mass growth in the first cosmic gigayear. The one reported here is the highest-redshift measurement of the cold and dense molecular gas to date. The host galaxy is unresolved, and the line luminosity implies a molecular reservoir of M(H2) = (2.2 ± 0.2) × 1010 M ⊙, assuming a CO spectral line energy distribution typical of high-redshift quasars and a conversion factor α = 0.8 M ⊙ ( K km s − 1 pc 2 ) − 1 . We model the cold dust spectral energy distribution to derive a dust mass of M dust = (1.7 ± 0.6) × 108 M ⊙ and thus, a gas-to-dust ratio ∼130. Both the gas and dust mass are remarkably similar to the reservoirs found for luminous quasars at z ∼ 6–7. We use the CO detection to derive an estimate of the cosmic mass density of H2, Ω H 2 ≃ 1.31 × 10 − 5 . This value is in line with the general trend suggested by literature estimates at z < 7 and agrees fairly well with the latest theoretical expectations of nonequilibrium molecular-chemistry cosmological simulations of cold gas at early times.

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HYPerluminous quasars at the Epoch of ReionizatION (HYPERION): A new regime for the X-ray nuclear properties of the first quasars

Zappacosta,

Piconcelli,

Fiore

et al. 2023

A&A

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The existence of luminous quasars (QSOs) at the epoch of reionization (EoR; i.e., z > 6) powered by well-grown supermassive black holes (SMBHs) with masses ≳109 M⊙ challenges models of early SMBH formation and growth. To shed light on the nature of these sources, we started a multiwavelength program based on a sample of 18 HYPerluminous quasars at the Epoch of ReionizatION (HYPERION). These are the luminous QSOs whose SMBHs must have had the most rapid mass growth during the first gigayear of the Universe and therefore acquired the largest mass at their respective epochs. In this paper, we present the HYPERION sample and report results from the first year of the planned three years of observations of the 2.4 Ms XMM-Newton Multi-Year Heritage program on which HYPERION is based. The goal of this program is to accurately characterise the X-ray nuclear properties of QSOs at the EoR. Through a joint X-ray spectral analysis of ten sources, covering the rest-frame ∼2 − 50 keV energy range, we report a steep average photon index (Γ ≈ 2.4 ± 0.1). No absorption is required at levels of 1021 − 1022 cm−2. The measured average Γ is inconsistent at ≥4σ level with the canonical value (Γ = 1.8 − 2) measured in QSOs at z < 6. Such a steep spectral slope is also significantly steeper than that reported in lower-z analog QSOs with similar luminosity or accretion rate, suggesting genuine redshift evolution. Alternatively, we can interpret this result as suggesting the presence of a very low energy cutoff Ecut ≈ 20 keV on a standard Γ = 1.9 power-law, the likes of which is rarely reported at lower z. We also report mild indications that, on average, HYPERION QSOs show higher levels of coronal soft X-rays at 2 keV compared to the accretion disk UV at 2500 Å than expected for lower-z AGN in the high-luminosity regime. We speculate that either a redshift-dependent coupling between the X-ray corona and accretion disk or intrinsically different coronal properties account for the steepness of the X-ray spectral slope, especially in the presence of powerful winds. The reported steep slopes, if confirmed in lower-luminosity regimes, may have an important impact on the design of next-generation X-ray facilities and future surveys designed to investigate the early Universe.

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Accurate Dust Temperature and Star Formation Rate in the Most Luminous z > 6 Quasar in the Hyperluminous Quasars at the Epoch of Reionization (HYPERION) Sample

Cited by 11 publications

References 49 publications

Physical Properties of Hyperluminous, Dust-obscured Quasars at z ∼ 3: Multiwavelength Spectral Energy Distribution Analysis and Cold Gas Content Revealed by ALMA

Physical Properties of Hyperluminous, Dust-obscured Quasars at z ∼ 3: Multiwavelength Spectral Energy Distribution Analysis and Cold Gas Content Revealed by ALMA

First Constraints on Dense Molecular Gas at z = 7.5149 from the Quasar Pōniuā‘ena

HYPerluminous quasars at the Epoch of ReionizatION (HYPERION): A new regime for the X-ray nuclear properties of the first quasars

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